TY - JOUR
T1 - Measurements of the optical performance of prototype TES bolometers for SAFARI
AU - Audley, M. D.
AU - De Lange, G.
AU - Ranjan, M.
AU - Gao, J. R.
AU - Khosropanah, P.
AU - Ridder, M. L.
AU - Mauskopf, Philip
AU - Morozov, D.
AU - Doherty, S.
AU - Trappe, N.
AU - Withington, S.
PY - 2014/9
Y1 - 2014/9
N2 - We have measured the optical response of prototype detectors for SAFARI, the far-infrared imaging spectrometer for the SPICA satellite. SAFARI's three bolometer arrays, coupled with a Fourier transform spectrometer, will provide images of a 2′×2′ field of view with spectral information over the wavelength range 34-210 μm. Each horn-coupled bolometer consists of a transition edge sensor (TES), with a transition temperature close to 100 mK, and a thin-film Ta absorber on a thermally-isolated silicon nitride membrane. SAFARI requires extremely sensitive detectors (NEP∼2×10-19 W/√Hz), with correspondingly low saturation powers (∼5 fW), to take advantage of SPICA's cooled optics. To meet the challenge of testing such sensitive detectors we have constructed an ultra-low background test facility based on a cryogen-free high-capacity dilution refrigerator, paying careful attention to stray-light exclusion, shielding, and vibration isolation. For optical measurements the system contains internal cold (3-30 K) and hot (∼300 K) black-body calibration sources, as well as a light pipe for external illumination. We discuss our measurements of high optical efficiency in prototype SAFARI detectors and describe recent improvements to the test facility that will enable us to test the full SAFARI focal-plane arrays.
AB - We have measured the optical response of prototype detectors for SAFARI, the far-infrared imaging spectrometer for the SPICA satellite. SAFARI's three bolometer arrays, coupled with a Fourier transform spectrometer, will provide images of a 2′×2′ field of view with spectral information over the wavelength range 34-210 μm. Each horn-coupled bolometer consists of a transition edge sensor (TES), with a transition temperature close to 100 mK, and a thin-film Ta absorber on a thermally-isolated silicon nitride membrane. SAFARI requires extremely sensitive detectors (NEP∼2×10-19 W/√Hz), with correspondingly low saturation powers (∼5 fW), to take advantage of SPICA's cooled optics. To meet the challenge of testing such sensitive detectors we have constructed an ultra-low background test facility based on a cryogen-free high-capacity dilution refrigerator, paying careful attention to stray-light exclusion, shielding, and vibration isolation. For optical measurements the system contains internal cold (3-30 K) and hot (∼300 K) black-body calibration sources, as well as a light pipe for external illumination. We discuss our measurements of high optical efficiency in prototype SAFARI detectors and describe recent improvements to the test facility that will enable us to test the full SAFARI focal-plane arrays.
KW - Infra-red bolometers
KW - Low-temperature detectors
KW - Optical testing
KW - Transition edge sensors
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U2 - 10.1007/s10909-013-0984-5
DO - 10.1007/s10909-013-0984-5
M3 - Article
AN - SCOPUS:84904750883
SN - 0022-2291
VL - 176
SP - 755
EP - 760
JO - Journal of Low Temperature Physics
JF - Journal of Low Temperature Physics
IS - 5-6
ER -