UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-23 18:09
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Conference: Bucharest University Faculty of Physics 2016 Meeting


Section: Optics, Spectroscopy, Plasma and Lasers


Title:
Evaluation of mid-ir photoconductive and photovoltaic detectors


Authors:
Laura Mihai(1), Adelina Sporea(1), A. Stancalie(1), I. Vata(2), M. Straticiuc(2), I. Burducea(2)


Affiliation:
1) National Institute for Laser, Plasma and Radiation Physics

Magurele, Romania

2)"Horia Hulubei” National Institute of Physics and Nuclear

Engineering, Magurele, Romania



E-mail
laura.mihai@inflpr.ro


Keywords:
MIR detectors, alpha radiation, proton radiation, spectral responsivity


Abstract:
Commercially available, uncooled mid-IR photovoltaic (InAs) and photoconductive (PbSe) detectors were tested under alpha particle and proton irradiation in order to evaluate their degradation for possible use in optical spectroscopy to be included in space missions. Their operating spectral sensitivity ranges from 0.8 μm to 5 μm for PbSe, and from 1 μm to 4.2 μm for InAs. Both types of detectors were irradiated with alpha particle irradiation at the Cyclotron irradiation facility (IFIN-HH) using beam charges of 0.285 mC for both samples and 2.26 mC for InAs detector and 2.44 mC for PbSe. Proton irradiation was performed with a 3MV Tandetron accelerator using energy of 3 MeV, a beam current of 5nA, with 10^14 and 10^16 particles/cm^2 fluences (2 irradiation steps). Detectors degradation was investigated in relation to their spectral responsivity changes, parameter measured before and after each irradiation step using Gooch and Housego OL Series 750 Automated Spectroradiometric Measurement System. Ge (OL 750-HSD-320C, 0.8 – 1.8 μm), PbS (OL 750-HSD-340C, 1.8 – 3.2 μm) and InSb (OL 750-HSD-360C, 3 – 5 μm) detectors were used as reference detectors, in conjunction with the OL 750-SDS-220 AC lock-in amplification signal detection system. The photovoltaic detector was coupled to the AC lock-in amplifier of the OL 750 through a DC ultra-low noise (6 pA/Hz1/2) transimpedance amplifier (104 – 106 V/A), while the photoconductive detector was connected to a high performance AC amplifier (equivalent noise signal 40 nV/Hz1/2, input impedance 104 Ω). The results showed that the PbSe detector was affected by alpha particles, decreasing the spectral responsivity around the wavelength 4.27 µm after the first irradiation and the total degradation after the second one, and increased with protons fluencies in the same spectral area (around 4.27µm). No noticeable changes in spectral responsivity were noticed in the case of InAs detector.


Acknowledgement:
The authors acknowledge the financial support of the Romanian Space Agency, under grant 67/2013. The procurement of the Gooch and Housego OL Series 750 instrument was financially supported by UEFISCDI, grant 8PM/2010.