The scintillating fiber camera is a type of three-dimensional track detector. Using this camera, we can observe the scintillation track produced along the path of a charged particle, and from its scintillation yield can determine the linear energy transfer (LET) distribution of the charged particle. Such observations are also possible for recoil (charged) particles produced by fast neutrons. From these data, we can estimate the LET distribution of individual charged particles or that of recoil particles produced by neutrons; and finally, we can estimate the dose equivalent due to charged particles and/or fast neutrons. For use as a dosimeter for fast neutrons produced by the interaction between cosmic-ray particles and wall materials of a manned spaceship in space, a 52 mm cubic scintillating fiber camera with a 75 mmΦ gated-image intensifier with a maximum counting rate of 30 Hz was constructed. The dosimeter consists of a stack of scintillation fibers with a sensitive volume of 52 mm × 52 mm × 52 mm and a 75 mm diameter image intensifier for readout from the scintillation fibers. The scintillation yields were measured for high-energy heavy ions such as carbon and argon ions. An energy resolution of 12% full-width half-maximum (FWHM) was obtained for penetrated argon ions of 650 MeV/n. These results demonstrate that this type detector is very useful as a dosimeter for high-energy cosmic rays and their secondary neutrons.
Dynamic range is a very important figure of merit to an imaging system in astronomy since it decides the range of brightness we can observe. This paper describes the design of a CMOS camera with extended dynamic range in which the CMOS sensor achieves high dynamic range by its dual slope response. We first established a model of how the dual slope response works, and gave a method to restore the image from dual slope response to linear response with the extended dynamic range. Then the data needed in the restoration to linear image was obtained in the laboratory by experiments using stable light source based on the model. At last the results of high dynamic range linear response images are shown using these experiment data.
In order to evaluate the radiation shielding efficiency on proton displacement damage for the CCDs that will be boarded space solar telescope project (SST) of China, based on the work of Janesick et. al's, a method is developed to get the stable defects produced by the incident protons. Then the proton caused degradation of the CCD specifications of charge transfer efficiency (CTE) and bulk dark current generation is calculated for SST after its 3-years-long mission on orbit and a 3mm thick aluminum shield is suggested for the CCDs of the mission. The method is a new attempt to predict the displacement-induced CTI and dark current together.
A prototype of correlation tracker (CT) designed for the Space Solar Telescope (SST) has been realized in National Astronomical Observatories of CAS. We designed a special optical system for the development and test of the CT system. We estimate the image motion by cross-correlation method via FFT and take full advantage of the real-valued FFT to reduce the amount of calculation. For a possible realization of the processing unit used in space, we use a "1 bit correlation" method, which will greatly simplify the hardware implementation of FFT. A resolution of 0.01" has been obtained corresponding to the object space of the telescope, with the -3dB closed-loop error cutoff frequency of 38Hz along x axis and 40Hz along y-axis achieved.
FeI 1.56 micrometers Zeeman-sensitive lines are very important and potential to measure the magnetic field of the deepest layer of the solar photosphere. The new generation polarimeter is designed and manufactured in this wavelength range. By use of the polarimeter mounted on the vertical spectrograph of the 2m solar telescope at Kitt Peak, we can observe the Stokes I, Q, U, Vv parameters simultaneously. The paper presents the introduction of the near infrared polarimeter and the polarmetry of a sunspot group.
The Solar Space Telescope (SST) is the largest scientific space project of China up to now. It engages to observe the transient and steady state solar hydrodynamic and magneto-hydrodynamic process over 2-D real time polarizing spectrum, UV, X-ray and H(alpha) image, and continuous time evolution with high spatial and temporal resolution in order to achieve a break through advance in solar physics. The EUV part of SST, the EUV telescope (EUT), consists of four telescopes with their detectors, which are parallel situated in a single telescope tube. Each telescope of the EUT adopts the normal-incidence principle with help of the multilayer technology and the primary mirror diameter is 12cm. The detectors of the EUT are constructed with EUV sensitive phosphors, fiber tapers, image intensifiers, CCDs, camera electronics and cooling blocks. Three telescopes of EUT are designed to achieve a spatial resolution of 0.5 arcsecond with a field of view (FOV) of 8.5'x8.5' in order to get the ever high-resolution image of the fine structure of the high temperature activities in solar corona and the fourth one is 85'x85' to have the full solar disk always in its field of view. In our presentation, the scientific objectives and the configuration of EUT are introduced.
Although the interest in PtSi infrared focal plane array (IRFPA) has waned due to its low quantum efficiency compared with InSb and HgCdTe arrays, it is very potential in observing brighter celestial objects. We explored the possibility of applying it to the observation of infrared solar spectrum. In the paper, the methods of the simulation and calibration in our observation are introduced and discussed in detail. Using this kind of camera, a new observational band (FeI 1.56 micrometers ) is added to the Two- Dimensional Multi-Band Solar Spectrograph at Yunnan Observatory. The dispersion for FeI 1.56 micrometers of the new infrared solar spectrograph is 0.0722 angstrom per pixel, and each vertical pixel represents 0.51 inch of solar disk. It is specially suitable for 2D spectroscopic observation of the deepest solar photosphere. Some primary observation results are also presented.
Although the interest in PtSi IR focal pane array has waned due to its low quantum efficiency compared with InSb and HgCdTe arrays, it is very potential in observing brighter celestial objects. We explored the possibility of applying it to the observation of IR solar spectrum. In the paper, the methods of the simulation and calibration in our observation are introduced and discussed in detail. Using this kind of camera, a new observational band is added to the 2D Multi-band Solar Spectrograph at Yunnan Observatory. The dispersion for FeI 1.56 micrometers of the new IR solar spectrograph is 0.0722 angstrom per pixel, and each vertical pixel represents 0.51 inch of solar disk. It is specially suitable for 2D spectroscopic observation of the deepest solar photosphere. Some primary observation results are also presented.
Two remote presence observations on Dec. 25, 1995 and Mar. 7, 1997 were achieved at the 1-m telescope of Yunnan Observatory. In this paper, the observations are introduced in detail. The technical methods in the remote presence observation are also discussed under the current circumstances of hardware and software in China. The brilliant prospects of the observational method are shown as well.
The performance of a TeKtronix scientific grade (Grade 1) CCD TK512CF with the METACHROMERII coating, applied as a detector for a solar spectroscopy, and the detailed description of the system configuration for operating the CCD are presented in this paper. The laboratory evaluation is made to the chip and the system prior to its installation on the solar spectrograph. Both the lab test and solar observation results show that the chip is a prospective powerful detector for modern solar spectroscopy.