PAUCam is a large field of view camera designed to exploit the field delivered by the prime focus corrector of the William Herschel Telescope, at the Observatorio del Roque de los Muchachos. One of the new features of this camera is its filter system, placed within a few millimeters of the focal plane using eleven trays containing 40 narrow band and 6 broad band filters, working in vacuum at an operational temperature of 250K and in a focalized beam. In this contribution, we describe the performance of these filters both in the characterization tests at the laboratory.
The PAUCam is an optical camera with a wide field of view of 1 deg x 1 deg and up to 46 narrow and broad band filters. The camera is already installed on the William Herschel Telescope (WHT) in the Canary Islands, Spain and successfully commissioned during the first period of 2015. The paper presents the main results from the readout electronics commissioning tests and include an overview of the whole readout electronics system, its configuration and current performance.
The DESI-GFA subsystem, used for Guiding, Focusing and Alignment, is one of the key parts for the DESI instrument (The Dark Energy Spectroscopic Instrument), planned for the Mayall 4-meter telescope at Kitt Peak National Observatory, Arizona, U.S. On this paper are presented the test bench facilities developed for the characterization of an e2v CCD230-42 CCD which is expected to be used at room temperature on each one of the ten small cameras composing the DESI-GFA system.
The PAU (Physics of the Accelerating Universe) project goal is the study of dark energy with a new photometric technique aiming at obtaining photo-z resolution for Luminous Red Galaxies (LRGs) roughly one order of magnitude better than current photometric surveys. To accomplish this, a new large field of view camera (PAUCam) has been built and commissioned at the William Herschel Telescope (WHT). With the current WHT corrector, the camera covers ~1 degree diameter Field of View (FoV). The focal plane consists of 18 2kx4k Hamamatsu fully depleted CCDs, with high quantum efficiency up to 1 μm. To maximize the detector coverage within the FoV, filters are placed in front of the CCD's inside the camera cryostat (made of carbon fiber material) using a challenging movable tray system. The camera uses a set of 40 narrow band filters ranging from ~4400 to ~8600 angstroms complemented with six standard broad-band filters, ugrizY. Here, we describe the camera and its first commissioning results. The PAU project aims to cover roughly 100 square degrees and to obtain accurate photometric redshifts for galaxies down to i<sub>AB</sub> ~ 22:5 detecting also galaxies down to i<sub>AB</sub> ~ 24 with less precision in redshift. With this data set we will obtain competitive constraints in cosmological parameters using both weak lensing and galaxy clustering as main observational probes.
The PAUCam is an optical camera with an array of 18 CCDs (Hamamatsu Photonics K.K.) and up to 45 narrow and
broad band filters. The camera will be installed on the William Herschel Telescope (WHT) in the Canary Islands, Spain.
In order to fulfill with the specifications for the camera readout system, it was necessary to test the different readout
electronics subsystems individually before to integrate the final readout work package, which is composed of 4
MONSOON (NOAO) front-ends, 6 fan out boards (MIX), each one driving up to 5 CCDs signals and a pre-amplification
stage (PREAMP) located inside the cryostat. To get the subsystems integration, it was built a small camera prototype
using the same technology as used in the main camera: a carbon fiber cryostat refrigerated by a cryotiger cooling system
but with capacity to allocate just 2 CCDs, which were readout and re-characterized to measure the electronics
performance as conversion factor or gain, readout noise, stability, linearity, etc. while the cross-talk was measured by
using a spot-light.
The aim of this paper is to review the whole process of assembly, integration and test (AIT) of the readout electronics
work package and present the main results to demonstrate the viability of the proposed systems to be use with the
The focal plane of the PAU camera is composed of eighteen 2K x 4K CCDs. These devices, plus four spares, were
provided by the Japanese company Hamamatsu Photonics K.K. with type no. S10892–04(X). These detectors are 200
μm thick fully depleted and back illuminated with an n-type silicon base. They have been built with a specific coating to
be sensitive in the range from 300 to 1,100 nm. Their square pixel size is 15 μm.
The read-out system consists of a Monsoon controller (NOAO) and the panVIEW software package. The deafualt CCD
read-out speed is 133 kpixel/s. This is the value used in the calibration process.
Before installing these devices in the camera focal plane, they were characterized using the facilities of the ICE (CSIC–
IEEC) and IFAE in the UAB Campus in Bellaterra (Barcelona, Catalonia, Spain).
The basic tests performed for all CCDs were to obtain the photon transfer curve (PTC), the charge transfer efficiency
(CTE) using X-rays and the EPER method, linearity, read-out noise, dark current, persistence, cosmetics and quantum
The X-rays images were also used for the analysis of the charge diffusion for different substrate voltages (VSUB).
Regarding the cosmetics, and in addition to white and dark pixels, some patterns were also found. The first one, which
appears in all devices, is the presence of half circles in the external edges. The origin of this pattern can be related to the
assembly process. A second one appears in the dark images, and shows bright arcs connecting corners along the vertical
axis of the CCD. This feature appears in all CCDs exactly in the same position so our guess is that the pattern is due to
Finally, and just in two devices, there is a spot with wavelength dependence whose origin could be the result of a
defectous coating process.
The Physics of Accelerating Universe Camera (PAUCam) is a new camera for dark energy studies that will be installed
in the William Herschel telescope. The main characteristic of the camera is the capacity for high precision photometric
redshift measurement. The camera is composed of eighteen Hamamatsu Photonics CCDs providing a wide field of view
covering a diameter of one degree. Unlike the common five optical filters of other similar surveys, PAUCam has forty
optical narrow band filters which will provide higher resolution in photometric redshifts. In this paper a general
description of the electronics of the camera and its status is presented.
PAUCam is a new camera for studying the physics of the accelerating universe. The camera will consist of eighteen
2Kx4K HPK CCDs: sixteen for science and two for guiding. The camera will be installed at the prime focus of the WHT
(William Herschel Telescope). In this contribution, the architecture of the readout electronics system is presented. Back-
End and Front-End electronics are described. Back-End consists of clock, bias and video processing boards, mounted on
Monsoon crates. The Front-End is based on patch panel boards. These boards are plugged outside the camera feed-through
panel for signal distribution. Inside the camera, individual preamplifier boards plus kapton cable completes the
path to connect to each CCD. The overall signal distribution and grounding scheme is shown in this paper.
The PAU Camera (PAUCam) [1,2] is a wide field camera that will be mounted at the corrected prime focus of the
William Herschel Telescope (Observatorio del Roque de los Muchachos, Canary Islands, Spain) in the next months.
The focal plane of PAUCam is composed by a mosaic of 18 CCD detectors of 2,048 x 4,176 pixels each one with a pixel
size of 15 microns, manufactured by Hamamatsu Photonics K. K. This mosaic covers a field of view (FoV) of 60 arcmin
(minutes of arc), 40 of them are unvignetted.
The behaviour of these 18 devices, plus four spares, and their electronic response should be characterized and optimized
for the use in PAUCam. This job is being carried out in the laboratories of the ICE/IFAE and the CIEMAT.
The electronic optimization of the CCD detectors is being carried out by means of an OG (Output Gate) scan and
maximizing it CTE (Charge Transfer Efficiency) while the read-out noise is minimized.
The device characterization itself is obtained with different tests. The photon transfer curve (PTC) that allows to obtain
the electronic gain, the linearity vs. light stimulus, the full-well capacity and the cosmetic defects. The read-out noise, the
dark current, the stability vs. temperature and the light remanence.
The Mid-resolution InfRAreD Astronomical Spectrograph (MIRADAS, a near-infrared multi-object echelle
spectrograph operating at spectral resolution R=20,000 over the 1-2.5μm bandpass) was selected in 2010 by the Gran
Telescopio Canarias (GTC) partnership as the next-generation near-infrared spectrograph for the world's largest
optical/infrared telescope, and is being developed by an international consortium. The MIRADAS consortium includes
the University of Florida, Universidad de Barcelona, Universidad Complutense de Madrid, Instituto de Astrofísica de
Canarias, Institut de Física d'Altes Energies, Institut d'Estudis Espacials de Catalunya and Universidad Nacional
Autonoma de Mexico, as well as probe arm industrial partner A-V-S (Spain). In this paper, we review the overall system
design for MIRADAS, as it nears Preliminary Design Review in the autumn of 2012.
The Physics of the Accelerating Universe (PAU) is a project whose main goal is the study of dark energy. For this purpose, a new large field of view camera (the PAU Camera, PAUCam) is being built. PAUCam is designed to carry out a wide area imaging survey with narrow and broad band filters spanning the optical wavelength range. The PAU Camera is now at an advance stage of construction. PAUCam will be mounted at the prime focus of the William Herschel Telescope. With the current WHT corrector, it will cover a 1 degree diameter field of view. PAUCam mounts eighteen 2k×4k Hamamatsu fully depleted CCDs, with high quantum efficiency up to 1 μm. Filter trays are placed in front of the CCDs with a technologically challenging system of moving filter trays inside the cryostat. The PAU Camera will use a new set of 42 narrow band filters ranging from ~4400 to ~8600 angstroms complemented with six standard broad-band filters, ugrizY. With PAUCam at the WHT we will carry out a cosmological imaging survey in both narrow and broad band filters that will perform as a low resolution spectroscopic survey. With the current survey strategy, we will obtain accurate photometric redshifts for galaxies down to <i>i<sub>AB</sub></i>~22.5 detecting also galaxies down to <i>i<sub>AB</sub></i>~24 with less precision in redshift. With this data set we will obtain competitive constraints in cosmological parameters using both weak lensing and galaxy clustering as main observational probes.
The PAUCam  is an optical camera with a 18 CCDs (Hamamatsu Photonics K.K.) mosaic and up to 42 narrow- and
broad-band filters. It is foreseen to install it at the William Herschel Telescope (WHT) in the Observatorio del Roque de
los Muchachos, Canary Islands, Spain. As required by the camera construction, a couple of test bench facilities were
developed, one in Madrid (CIEMAT) that is mainly devoted to CCDs read-out electronics development and filter
characterization , and another in Barcelona (IFAE-ICE) that has as its main task to characterize the scientific CCDs in
terms of Dark Current, CTE, QE, RON and many other parameters demanded by the scientific performance required.
The full CCDs characterization test bench layout, its descriptions and some optical and mechanical characterization
results are summarized in this paper.
The Physics of the Accelerating Universe (PAU) is a new project whose main goal is to study dark energy surveying the
galaxy distribution. For that purpose we need to determine the galaxy redshifts. The most accurate way to determine the
redshift of a galaxy and measure its spectral energy distribution (SED) is achieved with spectrographs. The PAU
collaboration is building an instrument (PAUCam) devoted to perform a large area survey for cosmological studies using
an alternative approach. SEDs are sampled and redshifts determined using narrow band filter photometry. For efficiency
and manufacturability considerations, the filters need to be placed close to the CCD detector surfaces on segmented filter
trays. The most innovative element of PAUCam is a set of 16 different exchangeable trays to support the filters arranged
in a jukebox-like changing mechanism inside the cryostat. The device is designed to operate within the range of
temperatures from 150K to 300K at the absolute pressure of 10<sup>-8</sup>mbar, being class-100 compliant.
The Physics of the Accelerating Universe (PAU) collaboration aims at conducting a competitive cosmology experiment.
For that purpose it is building the PAU Camera (PAUCam) to carry out a wide area survey to study dark energy.
PAUCam has been designed to be mounted at the prime focus of the William Herschel Telescope with its current optical
corrector that delivers a maximum field of view of ~0.8 square degrees. In order to cover the entire field of view
available, the PAUCam focal plane will be populated with a mosaic of eighteen CCD detectors. PAUCam will be
equipped with a set of narrow band filters and a set of broad band filters to sample the spectral energy distribution of
astronomical objects with photometric techniques equivalent to low resolution spectroscopy. In particular it will be able
to determine the redshift of galaxies with good precision and therefore conduct cosmological surveys. PAUCam will also
be offered to the broad astronomical community.
The European Southern Observatory (ESO) operates its Very Large Telescope (VLT) on Cerro Paranal (Chile) with to date 11 scientific instruments including two interferometric instruments and their numerous auxiliary systems at 4 Unit Telescopes (UTs) and 3 Auxiliary Telescopes (ATs). The rigorous application of preventive and corrective maintenance procedures and a close monitoring of the instruments' engineering data streams are the key ingredient towards the minimization of the technical downtime of the instruments. The extensive use of standardized hardware and software components and their strict configuration control is considered crucial to efficiently manage the large number of systems with the limited human and technical resources available. A close collaboration between the instrument engineers, the instrument scientists in instrument operation teams (IOTs) turns out to be vital to maintain and to the performance of the instrumentation suite. In this paper, the necessary tools, workflows, and organizational structures to achieve these objectives are presented.