Journal ArticleDOI
Radiation effects on a Ge:Ga photoconductive detector
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TLDR
In this paper, the authors investigated radiation effects on a Ge:Ga photoconductive infrared detector at low photon background level of 4×108 ph cm−2s−1, using Cobalt 60 as a gamma ray source.Abstract:
We have investigated radiation effects on a Ge:Ga photoconductive infrared detector at low photon background level of 4×108 ph cm−2s−1, using Cobalt 60 as a gamma ray source. The irradiation immediately induced spike noises which degrded NEP (short term effect), while it gradually increased responsivity (long term effect). After the removal of the gamma ray source, the spikes disappeared while the responsivity still stayed in a higher level and gradually decreased with a time scale of several hours. The responsivity-change-rate before and after the irradiation is smaller for a higher bias voltage. Finally we have made the first trial to cure the long term effect, using a flashing procedure and have found out its effectiveness.read more
Citations
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Journal ArticleDOI
Three-element stressed Ge:Ga photoconductor array for the infrared telescope in space.
TL;DR: A stressed Ge:Ga photoconductor array with three elements applied to the Infrared Telescope in Space satellite was fabricated and tested in experiments at 2.0 K in very low-photon-influx conditions and showed that the etaG had a time constant tau(c) that was proportional to N(ph)(-(1/2)).
Journal ArticleDOI
Optical efficiency of far-infrared photoconductors
TL;DR: An experimental and theoretical study to optimize the geometry of far-IR photoconductive detectors with diffraction-limited throughput found a rod-shaped detector geometry with square cross section, electrodes on the lateral faces, and a beveled backface to trap the radiation by total internal reflection to have nearly equal responsivity to the best detectors in integrating cavities.
Journal ArticleDOI
Radiation Effects on Stressed Ge:Ga Array Detector of Far-Infrared Surveyor on AKARI
Toyoaki Suzuki,Hidehiro Kaneda,Shuji Matsuura,Mai Shirahata,Takao Nakagawa,Yasuo Doi,Takashi Onaka,Yasunori Hibi,Hiroshi Shibai Mitsunobu Kawada +8 more
TL;DR: In this paper, the authors used a 100 MeV proton-beam irradiation test for an engineering model of the stressed Ge:Ga array, which simulated the South Atlantic Anomaly (SAA) passage.
Journal ArticleDOI
Compact Two-Dimensional Array of Stressed GE:GA Detectors
Yasuo Doi,Sin'itirou Makiuti,Haruyuki Okuda,Takao Nakagawa,Hiroshi Shibai,Mitsunobu Kawada,Norihisa Hiromoto,Mikio Fujiwara,Kenichi Okumura +8 more
TL;DR: In this paper, a 4 × 8 array of stressed Ge:Ga detectors was developed to minimize the size of the cameraoptics, and the detector's NEP was better than 1016 WHz-1/2.
Proceedings ArticleDOI
Ge:Ga far-infrared photoconductor 2D direct hybrid array
Norihisa Hiromoto,Mikio Fujiwara,Hiroshi Shibai,Takanori Hirao,Takao Nakagawa,Mitsunobu Kawada +5 more
TL;DR: In this article, a Ge:Ga photoconductor arrays fabricated on one chip, Si-pMOS readout integrated circuits, and a hybridization of them done by using indium bump technology are presented.
References
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Journal ArticleDOI
Low-Level Radiation Effects in Extrinsic Infrared Detectors
Abstract: Experimental data are presented on the effect of gamma irradiation at low dose levels of 10 Rads or less on the responsivity of arsenic-doped extrinsic IR detectors under operating conditions at 4.3 to 12°K. The observed large changes in responsivity under irradiation, and the subsequent transient behavior during a period of less than 1 minute immediately after the radiation is turned off, are strongly dependent on temperature, bias voltage, and IR flux level. The net effect following irradiation is always a responsivity increase; however, under some conditions, the increase can be preceded by a decrease. The responsivity change relaxes slowly, requiring more than one day for complete recovery of the detector to its pre-irradiation condition. The effects anneal rapidly at temperatures over 20°K. The observed phenomena can be explained by radiation-induced changes in the charge state of the levels associated with the majority IR-active dopant and the compensating impurities. The complex dependence of the responsivity changes on the operating conditions is explained in terms of competing processes involved in capture, recombination, and sweepout of radiation-generated electrons and holes. The physical mechanisms and a qualitative model offering a possible explanation of the effect of temperature, bias, and IR flux level are discussed.
Journal ArticleDOI
Infrared telescope on spacelab 2.
D. Koch,Giovanni G. Fazio,Wesley A. Traub,George H. Rieke,T. N. Gautier,William F. Hoffmann,F. J. Low,W. Poteet,E. W. Urban,L. Katz +9 more
TL;DR: The infrared telescope (IRT) on Spacelab 2 will be the first cryogenically cooled telescope operated from the Orbiter as mentioned in this paper, which is used to map extended sources of low surface brightness infrared emission, including the zodiacal light, the galactic plane and extragalactic regions.
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Girl — the German infrared laboratory for spacelab
TL;DR: GIRL as discussed by the authors is a liquid helium cooled 50 cm telescope equipped with four focal plane instruments dedicated to astronomical and aeronomical observations, including a detector array, a photopolarimeter, an Ebert-Fastie-spectrometer and a Michelson-interferometer.