Development of STJ with FD-SOI cryogenic amplifier as a far-infrared single photon detector for COBAND experiment

Transcription

1 Development of STJ with FD-SOI cryogenic amplifier as a far-infrared single photon detector for COBAND experiment 17 th International workshop on Low Temperature d Detectors (LTD17) Jul , 2017 / Kurume City Plaza, Kurume Yuji Takeuchi (Univ. of Tsukuba) S.-H.Kim, T.Iida, K.Takemasa, K.Nagata, C.Asano, S.Yagi, R.Wakasa (U of Tsukuba), H.Ikeda, T.Wada, K.Nagase (ISAS/JAXA), S.Matsuura (Kwansei gakuin U), Y.Arai, I.Kurachi, M.Hazumi (KEK), T.Yoshida, T.Nakamura, M.Sakai, W.Nishimura (U of Fukui), S.Mima, K.Kiuchi (RIKEN), H.Ishino, A.Kibayashi (Okayama U), Y.Kato (Kindai U), G.Fujii, S.Shiki, M.Ukibe, M.Ohkubo (AIST), S.Kawahito (Shizuoka U), E.Ramberg, P.Rubinov, D.Sergatskov (FNAL), S.-B.Kim (Seoul National U) COBAND collaboration 1

2 COBAND (COsmic BAckground Neutrino Decay) Search for Neutrino decay in Cosmic background neutrino To be observed as far infrared photons of ~50 m COBAND Rocket Experiment 200-sec measurement at an altitude of 200~300km Aiming at a sensitivity to years for the neutrino lifetime ν 1 γ ν 3 ν 2 ν 3 ν 1 ν 2 γ ν 3 ν 2 ν 3 ν 1 ν 2 2

3 Neutrino Decay signal and backgrounds Surface brightness I [MJy/sr] 100 CIB summary from Matsuura et al.(2011) Zodiacal Emission Zodiacal Light ISD DGL SL Integrated flux from galaxy counts 10 CMB C B decay 100 wavelength [ m] 1000 Zodiacal Emission I ZE =8MJy/sr Neutrino Decay I ν =25kJy/sr τ = yrs m 3 = 50 mev No other source has such a sharp edge structure!! 3

4 Proposal for COBAND Rocket Experiment Aiming at a sensitivity to ν lifetime for τ ν 3 = Ο yrs JAXA sounding rocket S-520 Telescope with 15cm diameter and 1m focal length At the focal point, a diffraction grating covering =40-80 m and an array of photo-detector pixels of 50( ) x 8( ) are placed. Each pixel has 100 mx100 m sensitive area. θ 4

5 COBAND rocket experiment sensitivity m 31 2 = ev 2 m i < 0.23eV 200-sec measurements with a sounding rocket 15cm dia. and 1m focal length telescope and grating in 40~80 m range Each pixel in 100 m 100 m 8 50pix. array counts number of photons L-R SM =0.02, M(W 2 )=715GeV COBAND rocket 200sec meas. x100 improvement! S.H.Kim et. al (2012) Mirizzi et. al (2007) 5

6 Requirements for the photo-detector in COBAND rocket experiment Sensitive area of 100 m 100 m for each pixel High detection efficiency for a far-infrared single-photon in =40 m~80 m Dark count rate less than 300Hz (expected real photon rate) NEP = ε γ 2f γ ~ WΤ Hz We are trying to achieve NEP ~10 19 WΤ Hz by using Superconducting Tunneling Junction detector Cryogenic amplifier readout 6

7 500pA/DIV Leakage Nb/Al-STJ development at CRAVITY 50 m sq. Nb/Al-STJ fabricated at CRAVITY I T~300mK w/ B field Leakage V 100nA 10nA 1nA 100pA 0.1nA 0.2mV/DIV Temperature(K) I leak ~200pA for 50 m sq. STJ, and achieved 50pA for 20 m sq. This satisfies our requirement! Far-infrared single photon detection is feasible with this Nb/Al-STJ device and a cryogenic amplifier which can be deployed in close proximity to the STJ. 7

8 -Ids Ids Channel Width : W 1mA 1 A 1nA FD-SOI-MOSFET at cryogenic temperature FD-SOI : Fully Depleted Silicon On Insulator -2 Channel Length : L ~50nm Id-Vg curve of W/L=10 m/0.4 m at Vds =1.8V ROOM 3K p-mos -1.5 Vgs (V) Very thin channel layer in MOSFET on SiO2 No floating body effect caused by charge accumulation in the body FD-SOI-MOSFET is reported to work at 4K 0 1mA 1 A 1nA 1pA JAXA/ISIS AIPC 1185, (2009) J Low Temp Phys 167, 602 (2012) ROOM 3K n-mos Vgs (V) Both p-mos and n-mos show excellent performance at 3K and below. 8

9 150mV 8mV 10mV SOI prototype amplifier for demonstration test T=350mK INPUT 1nF V Test pulse Amplifier stage Buffer stage 100 s OUTPUT Test pulse input through C=1nF at T=3K and 350mK Power consumption: ~100μW Output load: 1M and ~0.5nF We can compensate the effect of shifts in the thresholds by adjusting bias voltages. 9

10 Vss Vdd STJ response to laser pulse amplified by Cold amplifier 465nm laser pulse through optical fiber 10M STJ 4.7 F GND 3 He sorption cold stage T~350mK Cold amp. output STJ SOI 4.7 F Cold amp. input monitor We connect 20 m sq. Nb/Al-STJ and SOI amplifier on the cold stage through a capacitance 10

11 Amp.OUT [μv] Amp.IN [μv] STJ response to laser pulse amplified by Cold amplifier Input signal to SOI amp. from STJ T~350mK PW~230μW 50 18μV Output signal from SOI amplifier 1.2mV time [μsec] 512x averaged time [μsec] We observe 20 m sq. Nb/Al-STJ responses to laser pulses of =465nm amplified by SOI amplifier situated at T=350mK 11

12 Summary We propose COBAND experiment to search for neutrino radiative decay in cosmic neutrino background. Requirements for the detector is a photo-detector with NEP~10-19 W/ Hz. Nb/Al-STJ array with a diffractive for the sounding rocket experiment. Nb/Al-STJs fabricated at CRAVITY satisfy our requirements. Cryogenic FD-SOI amplifiers are under development and we demonstrated STJ signal amplification by a prototype SOI amplifier at T~350mK. Improvement of the neutrino lifetime lower limit up to O( yrs) is feasible for 200-sec measurement in a rocket-borne experiment with the detector. * SOI design in this work is supported by VDEC, the U. Tokyo in collaboration with Synopsys, Inc., Cadence Design Systems, Inc., and Mentor Graphics, Inc. 12