The High Throughput X-ray Spectroscopy Mission XMM-Newton of the European Space Agency (ESA) was launched on December 10, 1999 by an Ariane V rocket. The satellite observatory uses three grazing incidence telescopes coupled to reflection grating spectrometers and x-ray CCD cameras. Each x-ray telescope consists of 58 Wolter I mirrors which are nested in a coaxial and cofocal configuration. The XMM-Newton Science Operation Center has completed a coherent program for the in- orbit calibration and performance verification of the x-ray observatory. This paper presents first measurement results of the x-ray telescopes image quality and effective area obtained during this campaign.

The activities during the instrument calibrations are summarized and first data are presented. The main instrument features, the line-spread function and the effective area, are discussed and the status of the in-flight calibrations is summarized.

The combined effective area of the three EPIC cameras of the XMM-Newton Observatory, offers the greatest collecting power ever deployed in an X-ray imaging system. The resulting potential for high sensitivity, broad-band spectroscopic investigations demands an accurate calibration. This work summarizes the initial in-orbit calibration activities that address these requirements. We highlight the first steps towards effective area determination, which includes the maintenance of gain CTI calibration to allow accurate energy determination. We discuss observations concerning the timing and count-rate capabilities of the detectors. Finally we note some performance implications of the optical blocking filters.

After the launch of Chandra, it was realized that low energy protons (below approximately 300 keV) are funnelled by grazing incident mirrors onto the focal plane detectors. Front illuminated CCD detectors are very sensitive to soft protons causing radiation damage in their electrode structures and transfer channels. The back-illuminated 280 micrometer thick fully depleted pn-CCD of the European Photon Imaging Camera (EPIC) on board the X-ray Multi Mirror mission (XMM) is by far less sensitive to low energy proton radiation. Commanding the camera in a special low gain mode, even allows to directly measure proton spectra and event patterns up to 300 keV per pixel. At the 3 MV Van-de-Graaff accelerator of the Institute for Physics in Tubingen we have irradiated and tested a 3 cm² flight-like pn-CCD with protons from 1 to 300 keV up to a fluence of 1.4 (DOT) 10⁹ protons/cm². This is about a factor of 1000 above the expected solar proton fluence for a 10 year XMM-Newton mission under nominal operational conditions. In this paper we given an overview of the proton irradiation experiment, discuss the performance of the detector after proton irradiation and finally present proton spectra directly measured with the pn-CCD on board XMM-Newton during solar flares. In addition, we briefly describe the precautionary measures taken to minimize the proton radiation dose of the EPIC CCD detectors in orbit.

Swift is a first of its kind multiwavelength transient observatory for gamma-ray burst astronomy. It has the optimum capabilities for the next breakthroughs in determining the origin of gamma-ray bursts and their afterglows as well a using bursts to probe the early Universe. Swift will also perform the first sensitive hard X-ray survey of the sky. The mission is being developed by an international collaboration and consists of three instruments, the Burst Alert Telescope (BAT), the X-ray Telescope (XRT), and the Ultraviolet and Optical Telescope (UVOT). The BAT, a wide-field gamma-ray detector will detect approximately 1 gamma-ray burst per day with a sensitivity 5 times that of BATSE. The sensitive narrow-field XRT and UVOT will be autonomously slewed to the burst location in 20 to 70 seconds to determine 0.3 - 5.0 arcsec positions and perform optical, UV, and X-ray spectrophotometry. On-board measurements of redshift will also be done for hundreds of bursts. Swift will incorporate superb, low-cost instrument using existing flight-spare hardware and designs. Strong education/public outreach and follow-up programs will help to engage the public and astronomical community. Swift has been selected by NASA for development and launch in 2003.

The Burst Alert telescope (BAT) is one of 3 instruments on the Swift MIDEX spacecraft to study gamma-ray bursts (GRBs). The BAT instrument is the instrument that first detects the GRB and localizes the burst direction to an accuracy of 1 - 4 arcmin within 10 sec after the start of the event. These locations cause the spacecraft to autonomously slew to point the two narrow-FOV instruments at the burst location within 20 - 70 sec to make follow-up x-ray and optical observations. BAT is a wide-FOV coded-aperture instrument with a CdZnTe detector plane. The detector plane is composed of 32,768 pieces of CdZnTe (4 X 4 X 2 mm), and the coded-aperture mask is composed of approximately 50,000 pieces of lead (5 X 5 X 1 mm) with a 1-m separation between mask and detector plane. The BAT operates over the 10 - 150 keV energy range with approximately 7 keV resolution, a sensitivity of 0.2 ph/cm²-sec, and a 1.4 sr (half-coded) FOV. We expect to detect approximately 300 GRBs/yr for a 3-year mission. The BAT also performs an all-sky hard x-ray survey with a sensitivity of approximately 1 mCrab (systematic limit) and as a hard x- ray transient monitor.

The Swift Gamma Ray Burst Explorer will be launched in 2003 to observe hundreds of gamma-ray bursts per year and study their X-ray and optical afterglows, using a multiwavelength complement of three instruments: a wide-field Burst Alert Telescope (BAT), an X-Ray Telescope (XRT), and a UV/Optical Telescope (UVOT). The XRT is designed to study X-ray counterparts of the gamma-ray bursts and their afterglows, beginning 20 - 70 s from the time of the burst, and continuing for days or weeks. The XRT utilizes a superb mirror set built for JET-X and a state-of-the-art XMM/EPIC CCD detector to provide a sensitive broad-band (0.2 - 10 keV) X-ray imager with effective area of 110 cm² at 1.5 keV, field of view of 23.6 X 23.6 arcminutes, and angular resolution of 15 arcseconds (HEW). The sensitivity is 2 X 10^-14 erg/cm²s in 10⁴ seconds. The telescope electronics are designed to provide automated source detection and position reporting, with a position good to 2.5 arcseconds transmitted to the ground within 100 seconds of the burst detection. The XRT will operate in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning within about a minute after the burst and will follow each burst until it fades from view, typically monitoring 2 - 3 'old' bursts at a time while waiting for a new burst to be detected.

The Swift MIDEX mission is the first-of-its-kind observatory for multi-wavelength transient astronomy. The goal of the mission is to ascertain the origin of gamma-ray bursts and to utilize these bursts to probe the early universe. The Ultra- Violet/Optical Telescope (UVOT) is one of three telescopes flying aboard Swift. The UVOT is a working 'copy' of the Optical Monitor on the X-ray Multi-mirror Mission (XMM- Newton). It is a Ritchey-Chretien telescope with microchannel plate intensified charged-coupled devices (MICs) that provide sub-arcsecond imaging. These MICs are photon counting devices, capable of detecting very low signal levels. When flown above the atmosphere, the UVOT will have the equivalent sensitivity of a 4 m telescope on the ground, reaching a limiting magnitude of 24 for a 1000 second observation in the white light filter. A rotating filter wheel contains sensitive photometric broadband UV and visual filters for determining photometric redshifts. The filter wheel also contains UV and visual grisms for performing low-resolution spectroscopy.

The Penn State University Department of Astronomy and Astrophysics has been active in the design of X-ray CCD cameras for astronomy for over two decades, including sounding rocket systems, the CUBIC instrument on the SAC-B satellite and the ACIS camera on the Chandra satellite. Currently the group is designing and building an X-ray telescope (XRT), which will comprise part of the Swift Gamma-Ray Burst Explorer satellite. The Swift satellite, selected in October 1999 as one of two winners of NASA Explorer contracts, will -- within one minute -- detect, locate, and observe gamma-ray bursts simultaneously in the optical, ultraviolet, X-ray, and gamma- ray wavelengths using three co-aligned telescopes. The XRT electronics is required to read out the telescope's CCD sensor in a number of different ways depending on the observing mode selected. Immediately after the satellite re-orients to observe a newly detected burst, the XRT will enter an imaging mode to determine the exact position of the burst. The location will then be transmitted to the ground, and the XRT will autonomously enter other modes as the X-ray intensity of the burst waxes and wanes. This paper will discuss the electronics for a laboratory X-ray CCD camera, which serves as a test bed for development of the Swift XRT camera. It will also touch upon the preliminary design of the flight camera, which is closely related. A major challenge is achieving performance and reliability goals within the cost constraints of an Explorer mission.

The Chandra X-ray Observatory, the x-ray component of NASA's Great Observatories, provides unprecedented subarcsecond imaging, imaging spectrometry, and high-resolution dispersive spectroscopy of cosmic x-ray sources. During the initial phase of operation, some of the focal-plane charge-coupled devices (CCDs) -- namely, the front-illuminated devices -- experienced an unanticipated increase in charge-transfer inefficiency (CTI). Investigation of this anomaly determined the root cause to be radiation damage by weakly penetrating protons, entering the telescope's aperture and scattered off the mirrors into the focal plane. Subsequent changes in operating procedures have slowed the rate of increase of the CTI of the front- illuminated CCDs to acceptable levels. There has been no measurable degradation of the back-illuminated CCDs.

This paper describes the development of CRMFLX, an ion model for the outer magnetosphere developed for scheduling periods when the Advanced CCD Imaging Spectrometer (ACIS) instrument onboard the Chandra X-ray Observatory can be safely moved into the focal plane position required for science observations. Because exposure to protons with energies of approximately 100 keV to 200 keV has been shown to produce an increase in the charge transfer inefficiency (CTI) of the ACIS instrument, a tool for predicting encounters with magnetospheric regions rich in these particles is required. The model is based on data from the EPIC/ICS instrument onboard the Geotail satellite and provides the user with flux values for 100 kev to 200 keV protons as a function of satellite position and the geomagnetic activity Kp index.

Front side illuminated CCDs comprising focal plane of the Chandra X-ray telescope have suffered some radiation damage in the beginning of the mission. Measurements of CTI and dark current at different temperatures led us to conclusion that the type of damage is inconsistent with the much studied type of damage created by protons with energies higher than 10 MeV. Intensive ground based investigation showed that irradiation of a CCD with low energy protons (about 100 keV) results in the device characteristics similar to the ones of the flight chips (very low dark current, the shape of the CTI temperature dependence). We were able to reliably determine that only image section of the flight chips was damaged and therefore only fast transfer from image to frame store section was affected. We have developed several techniques in order to determine the parameters of the electron traps introduced into the transfer channel of the irradiated device. One of them is based on the analysis of the amplitude of the signal in the pixels trailing the pixel that absorbed an X-ray photon of known energy. Averaging over large number of photons allowed us to get high signal/noise ratio even for pixels with extremely low signal far behind the X-ray event. Performing this analysis at different temperatures we were able to measure trap density, emission time constant, and trap cross section. Another technique is based on the analysis of the tail behind the events of very high amplitude, such as cosmic ray hits. We have developed a new scheme of clocking the device which prevents several rows of image section from being ever read out and keeps them moving back and forth. This so- called 'squeegee mode' improves CTI and can also be used to measure trap parameters, being especially effective in measuring long time constants. At least 4 different types of traps were detected, two of them with short time constant in the range from tens to a few hundred microseconds. The most damaging for the device performance are the traps with longer time constant in the millisecond range. The measurement of the trap parameters allows us to accurately model charge transfer inefficiency and helps to choose optimal operational parameters, and eventually will lead to techniques that may noticeably improve performance of a damaged CCD.

The ACIS instrument on-board the Chandra X-ray Observatory (CXO) experienced pronounced degradation in spectrometric performance during the spacecraft's orbital activation and calibration phase. This damage was associated with a sharp increase in charge-transfer inefficiency combined with relatively constant dark current. Damage occurred only during passage through the earth's radiation belts, and only when ACIS remained in the focal plane during the passage. Subsequent measurements and analyses support the conjecture that the damaging radiation entered through the Observatory's High-Resolution Mirror Assembly (HRMA) aperture. A mechanism whereby low-energy magnetospheric protons and heavier ions are scattered through the HRMA and reach the focal plane with just enough energy to stop in the CCD's charge transfer channel provides a reasonably consistent explanation of all observed phenomena. In this paper, we shall describe analyses which support this conclusion. We simulated the mirror surfaces and various path elements using a standard ion transmission code to generate a bi-directional reflectance distribution function (BRDF). We then convolved the BRDF with the geometry using a ray-trace code. This paper presents damage estimates using measured proton fluences and ground measurements of ACIS-type CCD damage versus proton energy and compares them with observed on-orbit damage.

The Chandra X-ray Observatory High Resolution Camera is an improved version of similar Microchannel Plate (MCP) based detectors that were previously used on the Einstein and ROSAT X-ray observatories. The HRC consists of two detectors in a common housing, and sharing some processing electronics. Only one detector operates at a time. The HRC-I is a 100 mm X 100 mm device that is used for wide field of view imaging with sub-arcsecond angular resolution. The HRC-S is a 300 mm X 30 mm device that is used to readout the Low Energy Transmission Grating Spectrometer (LETGS) providing very high spectral resolution. The main differences from previous missions are the larger format MCP's, radioisotope free MCP glass, and an active Cosmic Ray anti-coincidence shield. Event processing in the HRC is limited to digitizing selected signals from the readout device and transmitting these to the ground. As a result, it is possible to examine and screen the data during processing. Algorithms have been developed to identify non-X-ray events thereby reducing the detector background. Event screening can also detect and filter out 'bad' events that might otherwise degrade image quality.

The High Resolution Camera (HRC) on-board the Chandra X-ray Observatory (CXO) provides the highest resolution X-ray images of celestial sources ever taken. Unfortunately, ringing in the electronics compromises the position readout signals for some of the events. The compromised signals affect the angular resolution that can be achieved. We present an empirically derived algorithm that can be used in ground processing of the data to minimize the impact of the ringing on the calculated event positions.

The emergence of Silicon based microchannel plates (MCP's) has been awaited for a number of years, with many proposed advantages over standard glass MCPs for space-based detectors. Si should have a very low inherent background (< 0.01 events sec^-1 cm^-2), as well as being a low Z element with low stopping power for x, gamma and cosmic rays. The surface is oxidized and can be baked to very high temperatures (> 800 degrees Celsius), and will not react with photocathodes deposited on the surface. This could potentially allow opaque photocathodes, with their higher resolution and efficiency, to be used in the near UV/optical bands. Since the microchannel positions are determined photolithographically, the pattern will be uniform and coherent, resulting in more uniform flat fields and less differential non-linearity in the spatial response. Microchannel spacing could decrease to the micron regime, while size formats could increase. The potential advantages of Si MCPs encompass increased gain, stability, longevity, event rate, and QE. However, glass MCPs have a strong and successful heritage in space-based detector systems and the advantages of Si MCP's must be demonstrated in the laboratory before being considered for flight applications. We have tested some newly developed silicon (Si) MCP's provided by Nanosciences Corp. Although these are still in the developmental stage we have achieved a number of significant results. The gain, pulse height, response and gain uniformity, and quantum detection efficiency are very similar to glass MCP's. However the Si MCP background is approximately 0.02 events sec^-1 cm^-2 without shielding, a significant improvement over even low noise MCP's. The small samples we have tested are 25 mm format with 8 micrometer pore spacing, but they are taken from a 75 mm substrate, which offers the possibility of large MCP's in the near future. More testing and process development are underway to probe other operational parameters and optimize the manufacturing process.

We describe the development of an imaging microchannel plate detector for a new class of high resolution EUV spectrometer. The detector incorporates a front MCP coated with a CsI photocathode to enhance quantum efficiency, while the rear MCP, supplied by Photonis SAS for a European Space Agency Technology Research Program, represents one of the first uses of a 6 micron pore device in astronomy. The detector uses a unique design of charge division anode, the Vernier readout, enabling it to deliver a spatial resolution better than 15 microns FWHM. The detector forms an integral component of J- PEX, a sounding rocket EUV spectrometer operating at near- normal incidence, using multilayer coated gratings to deliver a resolution and effective area 10 times that of EUVE in the 225 - 245 angstrom band.

We use the transmission line modeling (TLM) technique to model the saturation of the gain in a microchannel plate. To this purpose we represent a generic channel multiplier by a distributed constant, unidimensional electrical network in which the internal structure of the channel wall is neglected. This network is analyzed with the TLM method, i.e. with the techniques developed for transmission lines and a simple system of time-dependent, nonlinear differential equations is derived. Then we consider the system in steady-state conditions and, by introducing a rational approximation of the nonlinear gain equation, we derive an exact analytical solution from which the gain and the voltage along the channel multiplier can be easily computed. Finally the model is used to fit a set of experimental data taken with a MCP photomultiplier, finding that the derived equations describe with satisfactory accuracy the measured data.

We report on the performance of 6 micrometer pore diameter Microchannel Plates (MCPs) fabricated in 50 X 50 mm² format, from both standard and radio-isotope free low noise glass, by Photonis SAS for a European Space Agency Technology Research Program. We compare them to MCPs manufactured by Photonis (the former Philips Photonics) for the High Resolution Camera (HRC) on NASA's Chandra X-ray observatory. The new MCPs represent a significant advance in MCP technology, having a much larger area than previously reported 6 micrometer plates, and demonstrating low noise 6 micrometer technology for the first time. The 6 micrometer plates are shown to be, mechanically, exceptionally well made with a defect density reduced by a factor of 2 - 5 compared to samples from the HRC flight blocks. They exhibit excellent gain and the expected 0.28 keV (Carbon K) X-ray quantum efficiency. The low noise plates have a very uniform response to X-rays but the standard glass MCPs do show inhomogeneity on both the global and multifiber scales.

The ROSINA-RTOF experiment on the ROSETTA satellite is designed to measure the elemental, isotopic and molecular composition of comet Wirtanen. The two detector units for the RTOF (reflection time of flight) mass spectrometer are based on microchannel plate detection of ions and the subsequent timing of these events. Time of flight mass spectroscopy using microchannel plate devices is widespread in commercial applications providing fast pulse performance (< 0.5 ns FWHM) that enables high speed timing accuracy (< 100 ps) in small lightweight packaging. We have used this heritage to provide a compact, lightweight, detector for the RTOF experiment based on standard 6 micrometer pore, 18 mm active area MCPs. The specific design of the RTOF detectors is based on the work of Wurz & Gubler. The performance characteristics are similar to equivalent commercial units with apparent pulse widths of 500 ps (< 250 ps de-convolved), with gain of approximately 10⁶, pulse height distributions of approximately 50% FWHM and background rates of < 0.5 events cm^-2 sec^-1.

We report on the construction and laboratory testing of pixellated CZT detectors mounted in a flip-chip, tiled fashion and read out by an ASIC, as required for proposed hard X-ray astronomy missions. Two 10 mm X 10 mm X 5 mm detectors were fabricated, one out of standard eV Products high-pressure Bridgman CZT and one out of IMARAD horizontal Bridgman CZT. Each was fashioned with a 4 X 4 array of gold pixels on 2.5 mm pitch with a surrounding guard ring. The detectors were mounted side by side on a carrier card, such that the pixel pitch was preserved, and read out by a 32-channel VA-TA ASIC from IDE AS Corp. controlled by a PC/104 single-board computer. A passive shield/collimator surrounded by plastic scintillator encloses the detectors on five sides and provides an approximately 40 degree field of view. Thus this experiment tests key techniques required for future hard X-ray survey instruments. The experiment was taken to Ft. Sumner, NM in May 2000 in preparation for a scientific balloon flight aboard the joint Harvard-MSFC EXITE2/HERO payload. Although we did not receive a flight opportunity, and are currently scheduled to fly in September 2000, we present our calibration data in the flight configuration together with data analysis techniques and simulations of the expected flight background spectrum.

Our collaboration is characterizing a prototype detector module designed for high energy X-ray astrophysics research covering the 20 - 250 keV energy range. The module consists of a three dimensional position sensitive CdZnTe detector, 25 mm X 25 mm X 2 mm, with 1 mm pitch crossed strip electrodes, an interleaved steering electrode, and an Application Specific Integrated Circuit (ASIC) for individual electrode readout. The newly developed readout system is compact, lightweight, has low power consumption and will lead to reduced system electronic noise. The detector is surrounded by a plastic anti-coincidence system for charged particles, and passive shielding that has been optimized based on results from two previous balloon flights. The first balloon flight test of the new detector module is scheduled for Fall 2000. In addition to our continuing balloon studies, we are investigating proton radiation damage effects and present preliminary results. After proton irradiation, the energy resolution is not significantly degraded, calibration photopeaks are down shifted by less than 10% in energy, and the depth of interaction dependence is nearly eliminated.

When an X-ray photon is photoabsorbed in the CCD, it generates a primary charge cloud expanding through the diffusion. A mesh experiment for the X-ray CCD enables us to specify the interaction position of the X-ray photon with subpixel resolution. Furthermore, we can directly measure the charge cloud shape that can be well expressed by Gaussian profile. When an X-ray photon enters the pixel (event pixel), the primary charge is mainly collected into the event pixel. When the X-ray landing position is close enough to the pixel boundary, the primary charge spills over the adjacent pixel forming split events. The X-ray event is sorted by the event pattern, how many pixels does the primary charge split, resulting various grades of the events. We can easily understand that there are three parameters coupled together: the X-ray landing position inside the pixel, the X-ray event pattern and the primary charge cloud shape. We can determine any one of them from the other two parameters. Since we know the charge cloud shape using the mesh experiment, we can calculate the X-ray landing position inside the event pixel using the grade of the event. We applied our method to the Ti- K X-rays for the CCD with 12 micrometer square pixel. Once the primary charge splits into adjacent pixel, we can determine the X-ray landing position with subpixel resolution. Using the three- or four-pixel split event, we obtained the accuracy of the X-ray landing position about 1 micrometer. For two-pixel split event, we obtained the similar position accuracy in the split direction while no improvement perpendicular to it. We will discuss what type of the CCD will be able to achieve the subpixel resolution for all X-ray photons.

CCDs can function as the X-ray spectrometer by counting the number of electrons created by the ionization of semiconductor atoms following the photoelectric absorption of an X-ray photon. In order to measure the incident X-ray energy correctly, we have to sum up all the electrons split over several pixels, thus the grade method is conventionally used. We will discuss the possible alternative to this method -- the fitting method --, which has several advantages over the grade method. By applying this method to the data taken with our CCD chip, we will show that the fitting method can improve the quantum efficiency, is applicable to the analysis of polarized X-ray events, and gives us insights on the structure of CCDs.

The front-illuminated CCD devices on board the Chandra X-ray observatory have been damaged by proton beam irradiation during radiation belt passage. The scattered ions such as protons created the traps in the buried n-channel of the CCD. The effect of proton radiation induced defects in Si is summarized. The generation and evolution of the irradiation defects is studied and its relationship with CCD performance is discussed. The methods for enhancement of dissociation of defects by biasing and/or light illumination are proposed to recover the performance of CCD.

AGILE is a light and effective instrument for the detection of gamma-ray sources in the energy range 30 MeV - 50 GeV within a large field of view. The instrument is planned to fly in the years 2002 - 2005, a period in which no other gamma-ray mission in the same energy range is foreseen. AGILE is made of a tungsten-silicon tracker, a CsI minicalorimeter, an anticoincidence system and an X-ray detector (10 - 40 keV). The tracker consists of 14 planes, each made of 2 layers of 16 single-sided, AC coupled, 410 micrometer thick silicon detectors. Each detector covers an area of 9.5 X 9.5 cm² and has a readout pitch of 242 micrometer with one floating strip. Four silicon detectors are bonded together creating a 'ladder' 38 cm long. The total number of readout channels is around 37000. The readout chip is the TAA1 (IDE- AS, Norway), an analog-digital, self triggering chip used in a very low power configuration (400 (mu) W/channel). A prototype silicon ladder and the complete readout chain have been tested at the CERN PS in July 1999. The final ladder has been tested in May 2000. We present the noise performances of the readout electronics in the very low power configuration, and the testbeam results obtained with the full AGILE ladder. The results are compared with GEANT simulations.

SuperAGILE is the X-ray stage of AGILE gamma-ray mission. It is devoted to monitor X-ray (10 - 40 keV) sources with a sensitivity better than 10 mCrab in one observing day and to detect X-ray transients in a field of view of 1.8 sr, well matched to that of the gamma ray tracker, with few arc-minutes position resolution. SuperAGILE is designed to exploit one additional layer of four silicon micro-strip detectors, for 1444 cm² of total geometrical area, on top of the AGILE tracker and a system of four mutually orthogonal one- dimensional coded masks to encode the X-ray sky. Low noise electronics based on ASICs technology is the front-end read out. We present here the instrumental and astrophysical performances of SuperAGILE as derived by Monte Carlo simulation and experimental tests.

A Bismuth Germanate (BGO) 'veto' shield surrounds on five faces the detector planes of the IBIS instrument on-board the satellite INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory). The Veto System provides anti-coincidence signals to the two imager layers covering the energy range from 20 keV to 10 MeV. The area to be shielded is about 8000 cm², and with a shield thickness of 20 mm, this leads to a total BGO crystal weight of about 115 kg. This paper describes the shield design, and how some scientific and engineering requirements are implemented. Also results from tests with the Engineering Model are presented. Particular emphasis is given to the electronic signal chain, and its response to overload particles, mainly high energy protons, expected in the INTEGRAL orbit (Elliptic Earth Orbit with 72 h period). The overload response has been studied in detail both with a built-in Light Emitting Diode (LED) in the laboratory, and at a proton beam facility. Based on the lab measurements the expected blinding of the shield in-orbit is around 1%. This is obtained with a simple, but optimized chain, consisting of a front-end amplifier and a bi-polar shaper, that provides input to the trigger generator. Results from beam tests with proton energies from 60 to 300 MeV are reported, and it is demonstrated that the proton pulses in terms of amplitude, shape and duration are very similar to the simulated ones, and thus confirm the expected system response.

Monitor of the All-sky X-ray Image (MAXI) is the first payload for the Japanese Experiment Module (JEM) on the International Space Station (ISS). It is designed for monitoring all-sky in the X-ray band. Its angular resolution and scanning period are about 1 arc-degree and 100 minutes, respectively. MAXI employs two types of X-ray camera. One is Gas Slit Camera (GSC), the detectors of which are one dimensional position sensitive proportional counters. Another is Solid-state Slit Camera (SSC). We mainly report on SSC. We employ a pair of SSCs, each of which consists of 16 CCD chips. Each CCD chips has 1024 X 1024 pixels, and the pixel size is 24 X 24 micrometer. The CCDs are to be operated at -60 degrees Celsius using Peltier coolers. Optical light is blocked by aluminum coat on the CCDs instead of fragile aluminized film. SSC achieves an energy resolution of 152 eV in FWHM at 5.9 keV. The energy range is 0.5 - 10 keV.

Gas proportional counter arrays based on the micro-well are an example of a new generation of detectors that exploit narrow anode-cathode gaps, rather than fine anodes, to create gas gain. These are inherently imaging pixel detectors that can be made very large for reasonable costs. Because of their intrinsic gain and room-temperature operation, they can be instrumented at very low power per unit area, making them valuable for a variety of space-flight applications where large-area X-ray imaging or particle tracking is required. We discuss micro-well detectors as focal plane imager for Lobster-ISS, a proposed soft X-ray all-sky monitor, and as electron trackers for the Next Generation High-Energy Gamma Ray mission. We have developed a fabrication technique using a masked UV laser that allows us both to machine micro-wells in polymer substrates and to pattern metal electrodes. We have used this technique to fabricate detectors which image X-rays by simultaneously reading out orthogonal anode and cathode strips. We present imaging results from these detectors, as well as gain and energy resolution measurements that agree well with results from other groups.

The requirement for future X-ray Astronomy instrumentation to exhibit a combination of good energy resolution and an extended energy range may be fulfilled by the development of a X ray detectors made from coupling a Silicon Drift Chamber (SDC), to a scintillation crystal. We report on such a detector made with an SDC of 3 mm diameter and using a Caesium Iodide [CsI(Tl)] scintillator. The radiation input window is located on the Si side of the assembly so than soft X-rays are directly detected by the SDC. This allows a minimum threshold of about 1 keV at 0 degrees Celsius to be obtained. The Silicon Drift Chamber acts also as a photodiode able to detect the scintillation light produced by the CsI(Tl), thus extending the energy range of such a device up to some MeV. The discrimination of events between these two detection layers is performed by using a pulse shape discriminator in order to differentiate between the different rise times of the collected charge. The detector concept is discussed on the basis of the results already achieved and the future developments foreseen.

LXeGRIT is a balloon-borne Compton telescope employing a large volume liquid xenon time projection chamber (LXe-TPC) as the central (gamma) -ray detector. It is designed to image (gamma) - rays in the energy range of approximately 200 keV to 20 MeV, with an angular resolution of about 3 degrees (1 sigma) at 2 MeV, within a field-of-view (FOV) of about 1 sr. The detector's energy and three-dimensional spatial resolution as measured during pre-flight calibration experiments, are (Delta) E_1xe/E equals 8.8% (root)1MeV/E and < 1 mm RMS, respectively. The detection efficiency for Compton events varies between 1.5% and 4% depending on energy and event selection. We describe the instrument as flown on May 7, 1999 and review its overall performance at balloon altitude. The launch occurred at 13:26:54 UT from Ft. Sumner, New Mexico and the flight was terminated about 9 hours later. The Crab was in the instrument FOV for a few hours. Analysis of these data is in progress.

LXeGRIT is a balloon-borne Compton telescope based on a liquid xenon time projection chamber (LXeTPC) for imaging cosmic (gamma) -rays in the energy band of 0.2 - 20 MeV. The detector, with 400 cm² area and 7 cm drift gap, is filled with high purity LXe. Both ionization and scintillation light signal are detected to measure the energy deposits and the three spatial coordinates of individual (gamma) -ray interactions within the sensitive volume. The TPC has been characterized with repeated measurements of its spectral and Compton imaging response to (gamma) -rays from radioactive sources such as ²²Na, ¹³⁷Cs, ⁸⁸Y and Am-Be. The detector shows a linear response to g-rays in the energy range 511 keV - 4.4 MeV, with an energy resolution (FWHM) of (Delta) E/E equals 8.8% (root)1MeV/E. Compton imaging of ⁸⁸Y (gamma) -ray events with two detected interactions is consistent with an angular resolution of approximately 3 degrees (RMS) at 1.8 MeV.

Both the x-ray astrophysics and microanalysis communities need large format arrays of high-spectral-resolution x-ray detectors. To meet this need, we are fabricating multi-pixel arrays of our successful single pixel transition edge sensor (TES) x-ray microcalorimeters. We will adapt SQUID multiplexing technology already in use with our infrared TES bolometer arrays to reduce the wiring and power dissipation at the cold stage of our cryostat. Room temperature digital feedback electronics have also been developed to simplify the read-out of large numbers of pixels, and microfabrication techniques are being explored to enable the fabrication of large, close-packed arrays of TES microcalorimeters.

X-ray microcalorimeters using transition-edge sensors (TES) show great promise for use in astronomical x-ray spectroscopy. We have obtained very high energy resolution (2.8 eV at 1.5 keV and 3.7 eV at 3.3 keV) in a large, isolated TES pixel using a Mo/Au proximity-effect bilayer on a silicon nitride membrane. We will discuss the performance and our characterization of that device. In order to be truly suitable for use behind an x-ray telescope, however, such devices need to be arrayed with a pixel size and focal-plane coverage commensurate with the telescope focal length and spatial resolution. Since this requires fitting the TES and its thermal link, a critical component of each calorimeter pixel, into a far more compact geometry than has previously been investigated, we must study the fundamental scaling laws in pixel optimization. We have designed a photolithography mask that will allow us to probe the range in thermal conductance that can be obtained by perforating the nitride membrane in a narrow perimeter around the sensor. This mask will also show the effects of reducing the TES area. Though we have not yet tested devices of the compact designs, we will present our progress in several of the key processing steps and discuss the parameter space of our intended investigations.

We have fabricated a bridge-type structure for microcalorimeters with superconducting transition-edge sensors (TES). Instead of open space under a SiN_x membrane in conventional TES microcalorimeters, the bridge-type calorimeters have SiNx membrane floating on the Si substrate covered by a SiO₂ layer with a small gap of 30 - 50 micrometer. The bridge-type structure ensures that the calorimeters are mechanically tough. In addition, the thermal conductance can easily be controlled by changing the width, length, or thickness of the SiNx bridge. The calorimeters, of which operating temperature is 0.43 K, consist of a Ti/Au bilayer TES and an Au absorber. The x-ray events were read out by a DC-SQUID current amplifier with a 200-series array of SQUIDs placed on a 4.2 K stage. By analyzing the output pulse shapes, it has been found that the pulses are put into two categories. One has a fast rise time of approximately 3 microseconds and two decay components with time constants of approximately 10 microseconds and about approximately 130 microseconds. Another one has a longer rise time of approximately 10 microseconds and a single decay component of approximately 130 microseconds. It is considered that the pulse shapes depend on the x-ray absorption positions and the heat-flow pass.

We are developing a new sounding rocket payload, the Advanced Technology Solar Spectroscopic Imager (ATSSI), that will use an 8 X 8 array of transition edge sensors (TES) to obtain true spectroheliograms in a spectral bandpass spanning approximately 50 eV to approximately 3 keV. The TES array will be flown at the focus of a Wolter I telescope, where it will image as 3 arc-min by 3 arc-min field of view with a pixel resolution of approximately 6 arc-sec. In this way, it will obtain approximately 1000 individual spectra with an expected average energy resolution of approximately 3 eV FWHM. In addition to the TES array, the ATSSI will employ six multilayer telescopes with bandpasses centered on atomic lines at 17.1 angstrom (Fe XVII), 195.1 angstrom (Fe XII), 171.1 angstrom (Fe IX), 57.9 angstrom (Mg X), 98.3 angstrom (Ne VIII), and 150.1 angstrom (O VI). Two additional telescopes with bandpasses centered at 1550 angstrom (C IV) and 1216 angstrom (H I) will also be used. The eight narrowband telescopes will provide high spatial resolution (<EQ 1 arc- sec), full-disk solar images and will be complemented by two grating slit spectroheliographs. One grating will obtain high resolution spectroheliograms between 2750 angstrom and 2850 angstrom (for Mg II h- and k-line studies), and the other will be multilayer-based and will probe the Fe IX/X - O V/VI complex around 171 Angstrom (73 eV). With this set of instruments, we expect to explore more fully the nature of the energy flow between small-scale coronal, chromospheric and transition region structures, as well as to address the issue of what mechanisms are responsible for heating the quiescent solar atmosphere.

Composite microcalorimeters using neutron transmutation-doped germanium (NTD) thermistors have been tested at hard x-ray energies. We present a broad band spectrum showing the energy resolution at 60 keV to be approximately 50 eV. The application of these microcalorimeters to the field of nuclear line astrophysics is discussed.

We are presenting our recent developments to measure the electron antineutrino mass by studying the ¹⁸⁷Re (beta) - spectrum end-point with high resolution thermal detectors. We will discuss the preliminary results of an array of 8 bolometers made up of AgReO₄ absorbers (2.309 mg of total mass corresponding to a total ¹⁸⁷Re active mass of about 0.905 mg of with an expected (beta) total rate of about 1.3 Hz). Their risetime of 0.7 - 1.2 ms together with their energy resolution, ranging between 21 eV and 26 eV at 1.5 KeV, should allow to set a limit of about 10 - 12 eV after one year of real time measurements.

The XRS instrument on Astro-E is a fully self-contained microcalorimeter x-ray instrument capable of acquiring, optimally filtering, and characterizing events for 32 independent pixels. We have recently integrated a full engineering model XRS detector system into a laboratory cryostat for use on the electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory. The detector system contains a microcalorimeter array with 32 instrumented pixels heat sunk to 60 mK using an adiabatic demagnetization refrigerator. The instrument has a composite resolution of 8 eV at 1 keV and 11 eV at 6 keV with a minimum of 98% quantum efficiency and a total collecting area of 13 mm². This will allow high spectral resolution, broadband observations of plasmas with known ionization states that are produced in the EBIT experiment. Unique to our instrument are exceptionally well characterized 1000 Angstrom thick aluminum on polyimide infrared blocking filters. The detailed transmission function including the edge fine structure of these filters has been measured in our laboratory using a variable spaced grating spectrometer. This will allow the instrument to perform the first broadband absolute flux measurements with the EBIT instrument. The instrument performance as well as the results of preliminary measurements of Fe K and L shell at fixed electron energy, Fe emission with Maxwellian electron distributions, and phase resolved spectroscopy of ionizing plasmas will be discussed.

In the X-ray astrophysics community, the desire for wide- field, high-resolution, X-ray imaging spectrometers has been growing for some time. We present a concept for such a detector called a Position-Sensing Transition-edge sensor (PoST). A PoST is a calorimeter consisting of two Transition- Edge Sensors (TESs) on the ends of a long absorber to do one dimensional imaging spectroscopy. Comparing the rise time and energy estimates obtained from each TES for a given event, the position of that event in the PoST is determined. Energy is inferred from the sum of the two signals on the TESs. We have designed 7, 15, and 32 pixel PoSTs using our Mo/Au TESs and bismuth absorbers. We discuss the theory, modeling, operation and readout of PoSTs and the latest results from our development.

We have developed cryogenic detectors based on superconducting phase transition thermometers (SPTs) for applications in x-ray astronomy. For a detector, which was designed for 1- dimensional imaging, an energy resolution of 216 eV (5.9 keV) and a position resolution of about 200 micrometer has been demonstrated over an absorber length as long as 1 cm. Finally, the possibilities for achieving better resolving power, improved position resolution, larger active area and increased counting capability will be discussed.

We are developing detectors based on bulk superconducting absorbers coupled to superconducting transition edge sensors (TES) for high-resolution spectroscopy of hard X-rays and soft gamma-rays. We have achieved an energy resolution of 70 eV FWHM at 60 keV using a 1 X 1 X 0.25 mm³ Sn absorber coupled to a Mo/Cu multilayer TES with a transition temperature of 100 mK. The response of this detector is compared with a simple model using only material properties data and characteristics derived from IV-measurements. We have also manufactured detectors using superconducting absorbers with a higher stopping power, such as Pb and Ta. We present our first measurements of these detectors, including the thermalization characteristics of the bulk superconducting absorbers. The differences in performance between the detectors are discussed and an outline of the future direction of our detector development efforts is given.

Magnetic calorimeters for particle detection are based on the measurement of the change in magnetization of paramagnetic spins upon the deposition of energy. The use SQUID to measure the flux change of ions in a metallic host has been shown to make a fast detector with high energy resolution. Magnetic ions in a metal constitute a well defined thermodynamic system, the properties of which can be calculated with confidence. Such calculations allows one to optimize the parameters of the system, such a size and concentration, to maximize the sensitivity. Magnetic calorimeters appear particularly suited for use in the detection of hard x-rays since the resolution achievable with such devices decreases with increasing heat capacity as only the one third power. Experimental results on magnetic calorimeters are reviewed.

Cryogenic high-resolution X-ray spectrometers are typically operated with thin IR blocking windows to reduce radiative heating of the detector while allowing good x-ray transmission. We have estimated the temperature profile of these IR blocking windows under typical operating conditions. We show that the temperature in the center of the window is raised due to radiation from the higher temperature stages. This can increase the infrared photon flux onto the detector, thereby increasing the IR noise and decreasing the cryostat hold time. The increased window temperature constrains the maximum window size and the number of windows required. We discuss the consequences for IR blocking window design.

A feasibility study of megapixel microcalorimeter arrays, based on thermoelectric energy to voltage conversion and digital superconducting readout, is presented. The design concept originated from the philosophy of employing the simplest principles at the single-pixel level to enable large arrays without sacrificing energy resolution, fast operation speed, and quantum efficiency. Initial experimental tests confirm the basic predictions of theory, and show no major obstacle in achieving the desired characteristics.

The AGILE satellite is designed to observe emission in the energy range from 30 MeV to 50 GeV from a variety of celestial objects such as Galactic sources, Active Galactic Nuclei, gamma ray bursts, solar flares and unidentified objects as well as diffuse emission. It is intended to be operational for a period of 3 years from the foreseen launch date of 2002. In the intervening time the instrument will proceed from the design phase, through the construction, test and calibration to the flight ready status. In order to support these activities a dedicated Ground Support Equipment (GSE), including both mechanical and electrical items will be required. Herein we describe the architecture of the GSE with particular reference to the items devoted to the scientific data acquisition, archiving and processing and to the control of the detector position in the calibration beam facility.

The AGILE (Astro-rivelatore Gamma a Immagini LEggero) satellite is an accepted mission by the ASI (Italian Space Agency) for Small Scientific Payload as a powerful and cost- effective space mission dedicated to gamma-ray (30 MeV to 50 GeV) astrophysics during the years 2002 - 2005. The instrument is designed to achieve an optimal angular resolution (about 5' - 20' for intense sources) and a large field-of-view (better than 2 sr.). The AGILE scientific payload consists of a silicon-tungsten tracker, a Cesium Iodide mini-calorimeter, an anti-coincidence system made of plastic scintillators, fast read-out electronics and processing units. The mini- calorimeter detector is made of 2 orthogonal planes each one comprising 16 bars of CsI(Tl) each having a cross section of 1.5 X 2.3 cm and a length of 40 cm. The signal from each bar is collected by photo-diodes placed at both ends with the aim of: (1) obtaining information on the energy deposited in the bars by particles produced in the tracker and therefore contributing to the determination of the total energy. (2) detecting Gamma Ray Bursts and other impulsive events in the energy range 0.25 - 100 MeV. Two bars have been tested in the ITeSRE laboratory using ²⁴¹Am and ²²Na radioactive sources and at the CERN (European Center for Nuclear Radiation, Geneva) facilities using a beam of charged particles at the energy of 2 GeV/c. In this paper, after a short description of the experimental set-up, the performance of the two bars in terms of equivalent charge output, light attenuation, position and energy reconstruction as a function of the distance from the bars' center are reported. Moreover the results of a first approach to a Monte Carlo simulation of the bars are compared with experimental data.

AGILE is an innovative, cost-effective gamma-ray mission approved by the Italian Space Agency for the Program of Small Scientific Missions. The AGILE gamma-ray instrument is designed to detect and image photons in the 30 MeV - 50 GeV energy band with good sensitivity and very large field of view (FOV). AGILE is planned to be operational during the year 2002 and will be open to the international community for the study of gamma-ray sources. A main aim of the AGILE Data Handling system is to provide an on-board processing and filtering of events reducing the background rate to an acceptable value within a factor of 1 - 10 of the gamma-ray photon rate. In order to maximize the instrument FOV and detection efficiency for large-angle incident gamma-rays (and minimize the effect of particle backscattering from the mini-calorimeter), the data acquisition logic uses the combination of top and lateral AC signals and a coarse on-line direction reconstruction in the Si-tracker. Appropriate data buffers are envisioned to maximize data acquisition for impulsive gamma-ray events in the tracker and mini-calorimeter, respectively.

Ground calibrations have been completed in 1998 on the MOS-CCD focal planes of the European Photon Imaging Cameras (EPIC) of the X-ray Multi-Mirror (XMM) mission. The cameras have been calibrated as a whole, including the digital treatment performed in the EPIC MOS Controller (EMCR), where events are selected according to a library of preset patterns and some of their parameters saved for ground off line reconstruction. This paper presents results of the calibration data analysis about the X-ray event selection as a function of the EMCR configuration parameters and the X-ray event energy reconstruction on the pattern basis. Spectral performances of the cameras as well as the background rejection are presented as a function of the reconstruction scheme adopted.

The position dependency of gas amplification in the proportional counter (PC) is investigated. We have been developing one-dimensional position sensitive PCs for MAXI/GSC and HETE/WXM and found that anomalous gas amplification occurs in a high bias voltage, even while the PC is still operated in the proportional region. This effect depends on the position where the X-ray is absorbed. Therefore it appears as a hard tail, a soft tail, or a broad peak in the traditional PC, depending on the shape of the gain curve across the cell. It degrades the apparent energy resolution. Especially, a position sensitive proportional counter (PSPC) is operated with rather high bias voltage to give higher positional resolution. We encounter the difficulty to achieve good position and energy resolutions at the same time. In this work, we have examined the anomalous gas amplification for various gas mixtures of Xe + CO₂, Ar + CO₂ and Ar + CH₄, for gas gain up to approximately 20000, and for energies from 6 to 17 keV to understand the phenomena.

Numerical simulations are used to predict the cosmic-ray- induced background in a passively-shielded gas scintillation proportional counter. A pair of these detectors will be flown as focal plane instruments for a hard x-ray telescope balloon- borne experiment. The investigation begins with one- dimensional transmittance studies to determine optimum thickness and composition for additional passive shielding.These simulations suggest, within weight and other design constraints, 0.3 cm of lead would reduce shield leakage within the detector by an order of magnitude over the approximately 40 - 200 keV range while adding only negligibly to photon production within the shielding mass by hadronic interactions. Simulations of the entire as-built detector, on the other hand, predict this added shielding reduces shield leakage by only approximately 40% and the total background rate (including shield leakage and production but ignoring aperture flux) by only approximately 27%. The discrepancy between one-dimensional and full detector results is attributed to multiple Compton scattering of unattenuated hard x-rays within the pressure vessel which reduces initial photon energies to within detectable bounds and to leakage and production in the attached, unshielded, electronics housing. The aperture flux can be reduced by 90% by adding an aperture collimator for a final (shielded and collimated) detector total background in the 15 - 50 keV operating range of approximately 0.0043 cts-s^-1-cm^-2- keV^-1; a 65% reduction compared to the as-built detector. The dominant source of background remains cosmic diffuse and atmospheric gamma-ray leakage through the radiation shields and thin pressure vessel walls with a minor photon production contribution. Although this rate is higher than typically attained using active shielding techniques, a high S/N ratio is achieved by the combined telescope-detector system.

We describe a concept for a NASA SMEX Mission in which Gas Electron Multiplier (GEM) detectors, developed at CERN, are adapted for use in X-ray astronomy. These detectors can be used to obtain moderately large detector area and two- dimensional photon positions with sub mm accuracy in the range of 1.5 to 15 keV. We describe an application of GEMs with xenon gas, coded mask cameras, and simple circuits for measuring event positions and for anticoincidence rejection of particle events. The cameras are arranged to cover most of the celestial sphere, providing high sensitivity and throughput for a wide variety of cosmic explosions. At longer timescales, persistent X-ray sources would be monitored with unprecedented levels of coverage. The sensitivity to faint X-ray sources on a one-day timescale would be improved by a factor of 6 over the RXTE All Sky Monitor.

The PICsIT instrument is the high energy imager which together with a low-energy plane comprises one of the two main detectors of the INTEGRAL gamma-ray satellite due to be launched by ESA in late 2001. PICsIT consists of 8 identical modules of 512 Caesium Iodide (CsI) scintillation crystals. The calibration of the detection plane is performed at module level (in three parallel chains), and consists of characterizing each pixel in terms of resolution, gain and efficiency to a very high precision. The high precision and large number of pixels leads to the production of very large amounts of data which then leads to the requirement for a system capable of accumulating at a very high bit-rate; of archiving the data in a suitable format for later analysis; of visualizing these data as they are accumulated in a quick-look fashion in order to control the correct set-up of the test arrangement and the detector functionality during the test and of partially analyzing these extremely large quantities of data on-line so as to obtain the results essential for proceeding with the test process in a rapid manner and not to impede the data accumulation process. Herein we describe the test equipment currently in use for the flight model calibration.

IBIS is the imaging telescope onboard the ESA satellite INTEGRAL. IBIS will produce images of the gamma-ray sky in the region between 15 keV and 10 MeV by means of a position sensitive detection plane coupled with a coded aperture mask. The detection plane comprises two position sensitive layers: ISGRI and PICsIT. PICsIT is a 64 X 64 unit array of approximately 0.75 cm² crystals operating in the energy range between 150 keV and 10 MeV, arranged as 8 modules of 512 pixels. The PICsIT Qualification Model consists of one module and is therefore fully representative of the scientific performances of the flight model in terms of gain, linearity lower energy threshold and energy resolution. The performances evaluated from the analysis of the module calibration data are presented.

The Objective Crystal Spectrometer (OXS) is part of the SODART X-ray telescope onboard the future SPECTRUM-RONTGEN-GAMMA (SRG) mission. The SODART-OXS energy resolution is compared with those of the gratings of the XMM-NEWTON and CHANDRA telescopes. It is shown that for the high-energy region (2 - 10 keV) SODART-OXS has a substantially better energy resolution (up to 1 order of magnitude). However, the Bragg reflection principle of OXS leads to small photon numbers to be registrated in the detectors. Therefore, a careful choice of observation time and other parameters is necessary. We describe software including a complete ray-tracing procedure which simulates a whole SODART-OXS observation cycle to support the potential observer in his experiment planning. Presently, the software is limited to point sources.

The High Energy Transmission Grating Spectrometer of the Chandra X-Ray Observatory is a high spectral resolution instrument utilizing gold X-ray transmission gratings. The gratings have been subjected to a rigorous program of calibration, including testing at synchrotron facilities for the purpose of refining and testing the grating model. Here we conclude our investigation of the optical constants of gold, extending it below 2 keV to complete the coverage over the Chandra energy range. We investigate the carbon, nitrogen, oxygen and chromium edge structures introduced by the grating support membrane. Finally, we summarize the state of the grating model, identifying those energy regions where the residuals are most significant and suggesting where the model might be improved.

Even though it is recognized that the study of polarization from cosmic high-energy sources can give very important information about the nature of the emission mechanism, to date very few measurements have been attempted. For several years we have proposed the use of a thick CdTe array as a position sensitive spectrometer for hard X- and soft gamma-ray astronomy, a design which is also efficient for use as a polarimeter at energies above approximately 100 keV. Herein we describe the preliminary results of our study of a polarimeter based on 4096 CdTe microcrystals that we would like to develop for a high altitude balloon experiment. We present the telescope concept with a description of each subsystem together with some results on activities devoted to the optimization of the CdTe detector units' response. Furthermore we give an evaluation of the telescope performance in terms of achievable spectroscopic and polarimetric performance. In particular we will show the results of Monte Carlo simulations developed to evaluate the efficiency of our detector as a hard X ray polarimeter.

In response to the recent NASA-SMEX Announcement of Opportunity, our collaboration proposed Cyclone, the Cyclotron/Nuclear Explorer. Cyclone is a broadband pointed astrophysical observatory, combining the highest spectral resolutions (E/(Delta) E approximately 30 - 300) and angular resolutions (15') achieved in the optimized hard X-ray range (10 - 200 keV). The instrument consists of 19 co-aligned rotation modulation collimator (RMC) telescopes, each with a high spectral resolution, 6-cm diameter germanium detector (GeD) covering energies from 3 keV to 600 keV. Both the optics and detectors are actively shielded with 15-mm BGO to gain low background an high sensitivity to astrophysical sources. A 550-km altitude, circular equatorial orbit also minimizes background. Building strongly upon instrumental heritage from the High-Energy Solar Spectroscopic Imager (HESSI) program, Cyclone would be ready for launch by September 2003. The instrument design and expected performance are discussed, as well as a brief overview of scientific goals.

The chip XA1.3, low noise, self-triggered, data-driven and sparse readout multichannel front-end integrated circuit (ASICs), underwent to extensive calibration and tests, included temperature tests and power consumption tests. We describe the results of the tests and calibration and their impact, as front-end of the silicon micro-strip detectors, on the scientific performances of SuperAGILE experiment.