Abstract

Doped germanium photoconductors are the most sensitive detectors for astronomy in the wavelength range 40–240 μm. Under the extremely low background conditions encountered in cooled satellite instruments, these devices exhibit a number of transient effects, such as slow relaxation after a step change in illumination or bias, and spontaneous spiking at high signal levels. Such behavior can degrade the excellent instantaneous sensitivity of these detectors and create calibration uncertainties. These effects have been observed in the Ge:Be photoconductors and the stressed and unstressed Ge:Ga photoconductors in the Long Wavelength Spectrometer, one of the instruments on the Infrared Space Observatory. A systematic investigation of the transient response of the Long Wavelength Spectrometer detectors to a step change in illumination as a function of operating temperature, bias electric field, and illumination step size has been carried out to determine operating conditions that minimize the effects of this behavior. The transient effects appear to be due primarily to carrier sweep out, but they are not fully explained by existing models for transient response.

© 1996 Optical Society of America

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References

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  1. P. R. Bratt, “Impurity germanium and silicon infrared detectors,” Semicond. Semimet. 12, 39–142 (1977).
    [CrossRef]
  2. S. W. Teitsworth, R. M. Westervelt, E. E. Haller, “Nonlinear oscillations and chaos in electrical breakdown in Ge,” Phys. Rev. Lett. 51, 825–828 (1983).
    [CrossRef]
  3. N. M. Haegel, J. W. Beeman, P. N. Luke, E. E. Haller, “Transient photoconductivity in Ge:Be due to Be+ formation,” Phys. Rev. B 39, 3677–3682 (1989).
    [CrossRef]
  4. N. M. Haegel, E. E. Haller, “Transient response of Ge:Be and Ge:Zn far-infrared photoconductors under low background photon flux conditions,” Infrared Phys. 26, 247–261 (1986).
    [CrossRef]
  5. N. Sclar, “Properties of doped silicon and germanium infrared detectors,” Prog. Quantum Electron. 9, 149–257 (1984).
    [CrossRef]
  6. J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.
  7. Battelle-Institut e.V., Am Römerhof 35, D-6000 Frankfurt a.M. 90, Germany.
  8. M. Overhamm, Battelle-Institut e.V., Am Römerhof 35, D-6000 Frankfurt a.M. 90, Germany (personal communication, 1992).
  9. Model TRS, Infrared Labs, Tucson, Ariz. 85719.
  10. S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
    [CrossRef]
  11. Model JF4, Infrared Labs, Tucson, Ariz. 85719.
  12. S. M. Ryvkin, Photoelectric Effects in Semiconductors (Consul-tants Bureau, New York, 1964).
  13. B. I. Fouks, “Non-stationary behavior of low background photon detectors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 167–174, and references therein.
  14. N. M. Haegel, C. A. Latasa, A. M. White, “Transient response of infrared photoconductors: the roles of contacts and space charge,” Appl. Phys. A 56, 15–21 (1993).
    [CrossRef]
  15. E. E. Haller, R. E. MacMurray, L. M. Falicov, N. M. Haegel, W. L. Hansen, “Three holes bound to a double acceptor: Be+ in germanium,” Phys. Rev. Lett. 51, 1089–1091 (1983).
    [CrossRef]
  16. E. I. Gershenzon, G. N. Gol’tsman, A. P. Mel’nikov, “Binding energy of a carrier with a neutral impurity atom in germanium and in silicon,” Pis’ma Zh. Eksp. Teor. Fiz. 14, 281–282 (1971)[JETP Lett. 14, 185–186 (1971].
  17. M. C. Price, M. J. Griffin, S. E. Church, A. G. Murray, P. A. R. Ade, “Ionising radiation induced effects in doped germanium FIR photoconductors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 309–312.

1993

S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
[CrossRef]

N. M. Haegel, C. A. Latasa, A. M. White, “Transient response of infrared photoconductors: the roles of contacts and space charge,” Appl. Phys. A 56, 15–21 (1993).
[CrossRef]

1989

N. M. Haegel, J. W. Beeman, P. N. Luke, E. E. Haller, “Transient photoconductivity in Ge:Be due to Be+ formation,” Phys. Rev. B 39, 3677–3682 (1989).
[CrossRef]

1986

N. M. Haegel, E. E. Haller, “Transient response of Ge:Be and Ge:Zn far-infrared photoconductors under low background photon flux conditions,” Infrared Phys. 26, 247–261 (1986).
[CrossRef]

1984

N. Sclar, “Properties of doped silicon and germanium infrared detectors,” Prog. Quantum Electron. 9, 149–257 (1984).
[CrossRef]

1983

S. W. Teitsworth, R. M. Westervelt, E. E. Haller, “Nonlinear oscillations and chaos in electrical breakdown in Ge,” Phys. Rev. Lett. 51, 825–828 (1983).
[CrossRef]

E. E. Haller, R. E. MacMurray, L. M. Falicov, N. M. Haegel, W. L. Hansen, “Three holes bound to a double acceptor: Be+ in germanium,” Phys. Rev. Lett. 51, 1089–1091 (1983).
[CrossRef]

1977

P. R. Bratt, “Impurity germanium and silicon infrared detectors,” Semicond. Semimet. 12, 39–142 (1977).
[CrossRef]

1971

E. I. Gershenzon, G. N. Gol’tsman, A. P. Mel’nikov, “Binding energy of a carrier with a neutral impurity atom in germanium and in silicon,” Pis’ma Zh. Eksp. Teor. Fiz. 14, 281–282 (1971)[JETP Lett. 14, 185–186 (1971].

Ade, P. A. R.

S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
[CrossRef]

M. C. Price, M. J. Griffin, S. E. Church, A. G. Murray, P. A. R. Ade, “Ionising radiation induced effects in doped germanium FIR photoconductors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 309–312.

Barl, L.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Beeman, J. W.

N. M. Haegel, J. W. Beeman, P. N. Luke, E. E. Haller, “Transient photoconductivity in Ge:Be due to Be+ formation,” Phys. Rev. B 39, 3677–3682 (1989).
[CrossRef]

Beintema, D.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Bratt, P. R.

P. R. Bratt, “Impurity germanium and silicon infrared detectors,” Semicond. Semimet. 12, 39–142 (1977).
[CrossRef]

Church, S. E.

S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
[CrossRef]

M. C. Price, M. J. Griffin, S. E. Church, A. G. Murray, P. A. R. Ade, “Ionising radiation induced effects in doped germanium FIR photoconductors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 309–312.

de Graauw, T.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Emery, R. J.

S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
[CrossRef]

Falicov, L. M.

E. E. Haller, R. E. MacMurray, L. M. Falicov, N. M. Haegel, W. L. Hansen, “Three holes bound to a double acceptor: Be+ in germanium,” Phys. Rev. Lett. 51, 1089–1091 (1983).
[CrossRef]

Fouks, B. I.

B. I. Fouks, “Non-stationary behavior of low background photon detectors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 167–174, and references therein.

Gershenzon, E. I.

E. I. Gershenzon, G. N. Gol’tsman, A. P. Mel’nikov, “Binding energy of a carrier with a neutral impurity atom in germanium and in silicon,” Pis’ma Zh. Eksp. Teor. Fiz. 14, 281–282 (1971)[JETP Lett. 14, 185–186 (1971].

Gol’tsman, G. N.

E. I. Gershenzon, G. N. Gol’tsman, A. P. Mel’nikov, “Binding energy of a carrier with a neutral impurity atom in germanium and in silicon,” Pis’ma Zh. Eksp. Teor. Fiz. 14, 281–282 (1971)[JETP Lett. 14, 185–186 (1971].

Griffin, M. J.

S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
[CrossRef]

M. C. Price, M. J. Griffin, S. E. Church, A. G. Murray, P. A. R. Ade, “Ionising radiation induced effects in doped germanium FIR photoconductors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 309–312.

Haegel, N. M.

N. M. Haegel, C. A. Latasa, A. M. White, “Transient response of infrared photoconductors: the roles of contacts and space charge,” Appl. Phys. A 56, 15–21 (1993).
[CrossRef]

N. M. Haegel, J. W. Beeman, P. N. Luke, E. E. Haller, “Transient photoconductivity in Ge:Be due to Be+ formation,” Phys. Rev. B 39, 3677–3682 (1989).
[CrossRef]

N. M. Haegel, E. E. Haller, “Transient response of Ge:Be and Ge:Zn far-infrared photoconductors under low background photon flux conditions,” Infrared Phys. 26, 247–261 (1986).
[CrossRef]

E. E. Haller, R. E. MacMurray, L. M. Falicov, N. M. Haegel, W. L. Hansen, “Three holes bound to a double acceptor: Be+ in germanium,” Phys. Rev. Lett. 51, 1089–1091 (1983).
[CrossRef]

Haller, E. E.

N. M. Haegel, J. W. Beeman, P. N. Luke, E. E. Haller, “Transient photoconductivity in Ge:Be due to Be+ formation,” Phys. Rev. B 39, 3677–3682 (1989).
[CrossRef]

N. M. Haegel, E. E. Haller, “Transient response of Ge:Be and Ge:Zn far-infrared photoconductors under low background photon flux conditions,” Infrared Phys. 26, 247–261 (1986).
[CrossRef]

S. W. Teitsworth, R. M. Westervelt, E. E. Haller, “Nonlinear oscillations and chaos in electrical breakdown in Ge,” Phys. Rev. Lett. 51, 825–828 (1983).
[CrossRef]

E. E. Haller, R. E. MacMurray, L. M. Falicov, N. M. Haegel, W. L. Hansen, “Three holes bound to a double acceptor: Be+ in germanium,” Phys. Rev. Lett. 51, 1089–1091 (1983).
[CrossRef]

Hansen, W. L.

E. E. Haller, R. E. MacMurray, L. M. Falicov, N. M. Haegel, W. L. Hansen, “Three holes bound to a double acceptor: Be+ in germanium,” Phys. Rev. Lett. 51, 1089–1091 (1983).
[CrossRef]

Katterloher, R.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Latasa, C. A.

N. M. Haegel, C. A. Latasa, A. M. White, “Transient response of infrared photoconductors: the roles of contacts and space charge,” Appl. Phys. A 56, 15–21 (1993).
[CrossRef]

Luinge, W.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Luke, P. N.

N. M. Haegel, J. W. Beeman, P. N. Luke, E. E. Haller, “Transient photoconductivity in Ge:Be due to Be+ formation,” Phys. Rev. B 39, 3677–3682 (1989).
[CrossRef]

MacMurray, R. E.

E. E. Haller, R. E. MacMurray, L. M. Falicov, N. M. Haegel, W. L. Hansen, “Three holes bound to a double acceptor: Be+ in germanium,” Phys. Rev. Lett. 51, 1089–1091 (1983).
[CrossRef]

Mel’nikov, A. P.

E. I. Gershenzon, G. N. Gol’tsman, A. P. Mel’nikov, “Binding energy of a carrier with a neutral impurity atom in germanium and in silicon,” Pis’ma Zh. Eksp. Teor. Fiz. 14, 281–282 (1971)[JETP Lett. 14, 185–186 (1971].

Murray, A. G.

M. C. Price, M. J. Griffin, S. E. Church, A. G. Murray, P. A. R. Ade, “Ionising radiation induced effects in doped germanium FIR photoconductors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 309–312.

Overhamm, M.

M. Overhamm, Battelle-Institut e.V., Am Römerhof 35, D-6000 Frankfurt a.M. 90, Germany (personal communication, 1992).

Price, M. C.

S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
[CrossRef]

M. C. Price, M. J. Griffin, S. E. Church, A. G. Murray, P. A. R. Ade, “Ionising radiation induced effects in doped germanium FIR photoconductors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 309–312.

Ryvkin, S. M.

S. M. Ryvkin, Photoelectric Effects in Semiconductors (Consul-tants Bureau, New York, 1964).

Sclar, N.

N. Sclar, “Properties of doped silicon and germanium infrared detectors,” Prog. Quantum Electron. 9, 149–257 (1984).
[CrossRef]

Swinyard, B. M.

S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
[CrossRef]

Teitsworth, S. W.

S. W. Teitsworth, R. M. Westervelt, E. E. Haller, “Nonlinear oscillations and chaos in electrical breakdown in Ge,” Phys. Rev. Lett. 51, 825–828 (1983).
[CrossRef]

Valentijn, E. A.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Wensink, J. W.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Westervelt, R. M.

S. W. Teitsworth, R. M. Westervelt, E. E. Haller, “Nonlinear oscillations and chaos in electrical breakdown in Ge,” Phys. Rev. Lett. 51, 825–828 (1983).
[CrossRef]

White, A. M.

N. M. Haegel, C. A. Latasa, A. M. White, “Transient response of infrared photoconductors: the roles of contacts and space charge,” Appl. Phys. A 56, 15–21 (1993).
[CrossRef]

Young, E. T.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Appl. Phys. A

N. M. Haegel, C. A. Latasa, A. M. White, “Transient response of infrared photoconductors: the roles of contacts and space charge,” Appl. Phys. A 56, 15–21 (1993).
[CrossRef]

Infrared Phys.

N. M. Haegel, E. E. Haller, “Transient response of Ge:Be and Ge:Zn far-infrared photoconductors under low background photon flux conditions,” Infrared Phys. 26, 247–261 (1986).
[CrossRef]

S. E. Church, M. J. Griffin, P. A. R. Ade, M. C. Price, R. J. Emery, B. M. Swinyard, “Calibration and performance testing of doped-germanium photoconductors for the ISO Long Wavelength Spectrometer,” Infrared Phys. 34, 389–406 (1993).
[CrossRef]

Phys. Rev. Lett.

E. E. Haller, R. E. MacMurray, L. M. Falicov, N. M. Haegel, W. L. Hansen, “Three holes bound to a double acceptor: Be+ in germanium,” Phys. Rev. Lett. 51, 1089–1091 (1983).
[CrossRef]

Phys. Rev. B

N. M. Haegel, J. W. Beeman, P. N. Luke, E. E. Haller, “Transient photoconductivity in Ge:Be due to Be+ formation,” Phys. Rev. B 39, 3677–3682 (1989).
[CrossRef]

Phys. Rev. Lett.

S. W. Teitsworth, R. M. Westervelt, E. E. Haller, “Nonlinear oscillations and chaos in electrical breakdown in Ge,” Phys. Rev. Lett. 51, 825–828 (1983).
[CrossRef]

Pis’ma Zh. Eksp. Teor. Fiz.

E. I. Gershenzon, G. N. Gol’tsman, A. P. Mel’nikov, “Binding energy of a carrier with a neutral impurity atom in germanium and in silicon,” Pis’ma Zh. Eksp. Teor. Fiz. 14, 281–282 (1971)[JETP Lett. 14, 185–186 (1971].

Prog. Quantum Electron.

N. Sclar, “Properties of doped silicon and germanium infrared detectors,” Prog. Quantum Electron. 9, 149–257 (1984).
[CrossRef]

Semicond. Semimet.

P. R. Bratt, “Impurity germanium and silicon infrared detectors,” Semicond. Semimet. 12, 39–142 (1977).
[CrossRef]

Other

M. C. Price, M. J. Griffin, S. E. Church, A. G. Murray, P. A. R. Ade, “Ionising radiation induced effects in doped germanium FIR photoconductors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 309–312.

J. W. Wensink, W. Luinge, D. Beintema, E. A. Valentijn, T. de Graauw, R. Katterloher, L. Barl, E. T. Young, “Characteristics of the ISO Short Wavelength Spectrometer detec-tors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 339–344.

Battelle-Institut e.V., Am Römerhof 35, D-6000 Frankfurt a.M. 90, Germany.

M. Overhamm, Battelle-Institut e.V., Am Römerhof 35, D-6000 Frankfurt a.M. 90, Germany (personal communication, 1992).

Model TRS, Infrared Labs, Tucson, Ariz. 85719.

Model JF4, Infrared Labs, Tucson, Ariz. 85719.

S. M. Ryvkin, Photoelectric Effects in Semiconductors (Consul-tants Bureau, New York, 1964).

B. I. Fouks, “Non-stationary behavior of low background photon detectors,” in Proceedings of the European Space Agency Symposium on Photon Detectors for Space Instrumentation (ESA, Nordwijk, 1992), SP-356, pp. 167–174, and references therein.

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Figures (9)

Fig. 1.
Fig. 1.

Transient response of the three LWS detector types to rapid flashes (10 s on, 10 s off) of a FIR illuminator. The upper, middle, and lower panels show the response of Ge:Be, Ge:Ga(u), and stressed Ge:Ga(s), respectively. The three sets of pulses in each panel correspond to different illumination levels; the first pulse set in each panel corresponds to an illumination level of ∼4 × 107 photons s−1.

Fig. 2.
Fig. 2.

Transient response to a step change in illumination as a function of operating temperature, observed in a Ge:Ga(u) detector at 85 μm and 2 V cm−1 bias. The five response curves corresponding to different detector operating temperatures are shown as contiguous in time but were actually separated by 10 min to allow the detector operating temperature to be changed.

Fig. 3.
Fig. 3.

Experimental configuration used to measure the detector response to a step change in illumination.

Fig. 4.
Fig. 4.

Typical response curves to a step in illumination of (a) a Ge:Be detector operated at 3 K, 50 μm, with a bias field of 6 V cm−1; (b) a Ge:Ga(u) detector operated at 3 K, 85 μm, with a bias field of 2 V cm−1; (c) a Ge:Ga(s) detector operated at 1.85 K, 160 μm, with a bias field of 0.6 V cm−1. The illumination step was chosen to give a similar value of Δg (∼2 × 108 cm−3 s−1) in each case.

Fig. 5.
Fig. 5.

Results of a three time-constant fit to the step response of the Ge:Ga(u) detector operated at 3 K, 85 μm and a bias field of 2 V cm−1. The smooth curve is the best fit of the model to the data.

Fig. 6.
Fig. 6.

Dependence of fitted time constants on (a) illumination step size at a fixed bias of 2 V cm−1 and (b) bias at a fixed illumination step of 5 × 109 cm−3 s−1 for the Ge:Ga(u) detector. The operating temperature was 3 K.

Fig. 7.
Fig. 7.

Dependence of fitted time constants on (a) illumination step size at a fixed bias of 0.7 V cm−1 and (b) bias at a fixed illumination step of 7 × 108 cm−3 s−1 for the Ge:Ga(s) detector. The operating temperature was 1.85 K.

Fig. 8.
Fig. 8.

Dependence of fitted time constants on (a) illumination step size at a fixed bias of 6 V cm−1 and (b) bias at a fixed illumination step of 6 × 109 cm−3 s−1 for the Ge:Be detector. The operating temperature was 3 K.

Fig. 9.
Fig. 9.

Dependence of fitted time constants on detector operating temperature for (a) a Ge:Ga(u) detector at a fixed bias of 2 V cm−1 and a step size of 5 × 108 cm−3 s−1 and (b) a Ge:Be detector at a fixed bias of 6 V cm−1 and a fixed step size of 109 cm−3 s−1.

Tables (2)

Tables Icon

Table 1. Measured Performance Parameters of the LWS Detectors

Tables Icon

Table 2. Summary of the Power Law Indices Determined for t 1% as a Function of Δg, E b , and T from Figs. 6 9

Equations (1)

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I det = I 0 [ 1 + a 1   exp ( t / τ 1 ) + a 2  exp ( t / τ 2 )          + a 3.3   exp ( t / τ 3 ) ] .

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