Laboratory Characterization of a Ge-CCD Prototype for Future Near-Infrared Astronomical Instrumentation
Abstract
Germanium charge-coupled devices (Ge-CCDs) extend CCD imaging beyond the silicon cutoff and are candidate detectors for the near-infrared channel of future astronomical instruments, in particular the spectrographs of next-generation wide-field surveys. We report the laboratory characterization at Brookhaven National Laboratory (BNL) of a prototype fabricated at MIT Lincoln Laboratory. We describe the cryogenic test system and readout, and present measurements of the output waveform, dark current, readout noise, and X-ray response. The dark current at 94.69 K is 26.12 ± 0.08 e- pixel−1 s−1. Under 55Fe irradiation without on-chip binning, the charge generated by an X-ray is confined within 2×2 pixels, and the Mn Kα line has a full width at half maximum (FWHM) of 8.5 ± 0.1% for single-pixel events. Since the charge generated by X-rays above about 30 keV spreads over 3×3 or more pixels, the CCD was operated with 2×2 on-chip binning at higher energies. This yielded FWHMs of 8.4±0.4% at 30.9 keV (133Ba, ASCA grades 0, 2, 3, 4, and 6) and 7.45±0.04% at 59.5 keV (241Am, all grades). These results establish a baseline for the device and for the BNL test system. Measurements of the temperature dependence, optical response, and charge-transfer performance will connect this baseline to the requirements of near-infrared astronomical instruments.
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BibTeX
@misc{tamura2026laboratory,
title = {{Laboratory Characterization of a Ge-CCD Prototype for Future Near-Infrared Astronomical Instrumentation}},
author = {Emi Tamura and Juan Cruz Estrada Vigil and Prashansa Mukim and Giovanni Pinaroli and Christopher Leitz and Ilya Prigozhin and Kevan Donlon and Santiago Ezequiel Perez and Sven C. Herrmann},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.22785},
eprint = {2610.22785},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.22785},
}
RIS
TY - UNPB
TI - Laboratory Characterization of a Ge-CCD Prototype for Future Near-Infrared Astronomical Instrumentation
AU - Emi Tamura
AU - Juan Cruz Estrada Vigil
AU - Prashansa Mukim
AU - Giovanni Pinaroli
AU - Christopher Leitz
AU - Ilya Prigozhin
AU - Kevan Donlon
AU - Santiago Ezequiel Perez
AU - Sven C. Herrmann
PY - 2026
DA - 2026/10/16
PB - arXiv
DO - 10.48550/arxiv.2610.22785
UR - https://arxiv.org/abs/2610.22785
AB - Germanium charge-coupled devices (Ge-CCDs) extend CCD imaging beyond the silicon cutoff and are candidate detectors for the near-infrared channel of future astronomical instruments, in particular the spectrographs of next-generation wide-field surveys. We report the laboratory characterization at Brookhaven National Laboratory (BNL) of a prototype fabricated at MIT Lincoln Laboratory. We describe the cryogenic test system and readout, and present measurements of the output waveform, dark current, readout noise, and X-ray response. The dark current at 94.69 K is 26.12 ± 0.08 e^- pixel^−1 s^−1. Under ^55Fe irradiation without on-chip binning, the charge generated by an X-ray is confined within 2×2 pixels, and the Mn Kα line has a full width at half maximum (FWHM) of 8.5 ± 0.1% for single-pixel events. Since the charge generated by X-rays above about 30 keV spreads over 3×3 or more pixels, the CCD was operated with 2×2 on-chip binning at higher energies. This yielded FWHMs of 8.4±0.4% at 30.9 keV (^133Ba, ASCA grades 0, 2, 3, 4, and 6) and 7.45±0.04% at 59.5 keV (^241Am, all grades). These results establish a baseline for the device and for the BNL test system. Measurements of the temperature dependence, optical response, and charge-transfer performance will connect this baseline to the requirements of near-infrared astronomical instruments.
ER -