1Development of Superconducting Tunnel Junction Photon
Detector with SOI Preamplifier board to Search for Radiative
decays of Cosmic Background Neutrino	
Tsukuba Global Science Week 2014
Takuya Okudaira1, Shinhong Kim1, Yuji Takeuchi1, Kota Kasahara1,Ren Senzaki1,Koya Moriuchi1 Kenichi Takemasa1, Kenji Kiuchi1,
Tatsuya Ichimura1, Masahiro Kanamaru1, Hirokazu Ikeda2, Shuji
Matsuura2, Takehiro Wada2, Hirokazu Ishino3, Atsuko Kibayashi3,Satoru Mima4, Takuo Yoshida5, Ryuta Hirose5, Yukihiro Kato6, MasashiHazumi7, Yasuo Arai7 ,Erik Ramberg8, Jonghee Yoo8, Mark Kozlovsky8,Paul Rubinov8, Dmitri Sergatskov8, and Soo-Bong Kim9
University of Tsukuba1, JAXA/ISAS2, Okayama University3, RIKEN4 University ofFukui5, Kinki University6, KEK7 ,Fermilab8, Seoul National University9	2

STJ Detector	
Nb	Al	AlOx	

We are developing STJ photon detector forneutrino decay search (as Dr. Takeuchi slide)aiming at detecting single far infrared(50um) photonSTJ(Superconducting Tunnel Junction) detector issuperconducting photoelectric detector that composed of~400nm	

photon	Superconductor / Insulator /Superconductor 	
Incident photons break up cooper pairs in STJ,
the electrons from the broken cooper pairs tunnel
through the insulator layer	

quasiparticle(electron)	

Si	
Tc [K]	
Δ [meV]	

cooper pair	

insulator	

1100	

Nb	Al	

9.23	

1.20	

1.550	

0.172	

Since energy gap of Nb is ~1meV (Si:~1eV), the energy
resolution of STJ can be much better thansemiconductor detector.	

3Nb/Al-STJ	
Nb/Al-STJ is one of the candidate detector for neutrino decay search
The signal to infrared(1310nm) laser
Typical signal width is about 1us	
Because of this signal width 	

Requirement for leakage current ofNb/Al-STJ to detect single far infrared
photon is below 100pA. 	
But we haven’t achieved such leakage current yet…

To achieve leakage current below 100pA…	

• use better quality STJ or smaller STJ• operate STJ below 800mK 	
Temperature dependence of leakage current
with Nb/Al-STJ(100 x100um2)	

4

STJ array prototype for Neutrino decay search	
We processed STJ at AIST and KEK,
and measured distribution of infrared(1310nm) laser with STJ array2.9mm	

The distribution of laser from fiber is
expected to be Gaussian	

STJ chipcarrier	laser fiber	

STJ illuminated with blue laser 	

1.4mm	STJ Output[AU]	

The distribution of infrared light with STJ array 	

STJ array on the chip
The number of STJs : 10
The size of each STJ : 100um x100um

Black : Output from each STJ
Red : Gaussian fit	

3.45
SOI ΞϯϓҰମ‫ܕ‬௒఻ಋτϯωϧ઀߹ૉࢠʢSOI-STJʣ

SOI-STJ	

SOI ΞϯϓҰମ‫ܕ‬௒఻ಋτϯωϧ઀߹ૉࢠʢSOI-STJʣ͸ɼ‫ۃ‬௿ԹԼͰͷಈ࡞͕ใࠂ͞Εͨ FD-SOI MOSFET ‫ج‬൘্ʹ Nb/Al-STJ Λ௚઀‫ܗ‬੒ͨ͠ΞϯϓҰମ‫ܕ‬ͷޫ‫ݕ‬ग़‫͋Ͱث‬Δɽ
Nb/Al-STJ ͷ৴߸Λͨͩͪʹ૿෯͢Δ͜ͱͰɼNb/Al-STJ ͷ໰୊఺Ͱ͋ͬͨϊΠζͷܰ‫ݮ‬͕‫ظ‬଴͞ΕΔɽ·ͨɼूੵԽʹ༏Εͨ SOI ͱ૊Έ߹Θ͍ͤͯΔ͜ͱͰɼকདྷͷ STJ ΞϨΠԽʹ΋ରԠՄೳͰ͋Δɽ

We are also developing a new detector :SOI-STJ	*+,-.,/012-'45&67(0809:;!"#$%&'()

3.2

Silicon On Insulator (SOI)
Processing LSI on SiO2 insulator• Low Power to be operated• high speed• can operate at a few Kelvin
SOI-FET is suitable for amplifier for STJ signal'.4<STJ
has high energy resolution
ਤ 3.8: SOI-STJ ͷߏ଄

SOI-STJ ͷߏ଄Λਤ 3.8 ʹࣔ͢ɽSOI-STJ ͸૿෯ճ࿏͕‫ܗ‬੒͞Εͨ SOI ‫ج‬൘ͱ Nb/Al-STJ͔ΒͳΔɽճ࿏‫ج‬൘͸‫ࣜג‬ձࣾϥϐεηϛίϯμΫλʹ࡞੒Λґཔ͠ɼग़དྷ্͕ͬͨ‫ج‬൘্ʹ Nb/Al-STJ Λ௚઀‫ܗ‬੒͢Δɽ૿෯ճ࿏෦͸ SOI ٕज़ʹΑΓɼσόΠε૚ͱઈԑ૚Λަ‫ޓ‬ʹੵΈॏͶͨ 3 ࣍‫ݩ‬తͳूੵճ࿏ͱͳ͍ͬͯΔɽ֤૚ͷσόΠε͸ϏΞͱ‫ݺ‬͹ΕΔ W ͔ΒͰ͖ͨۚଐபͰ઀ଓ͞ΕΔɽͦͷճ࿏૚্ʹ௚઀ Nb/Al-STJ Λ‫ܗ‬੒͢ΔɽSTJ ‫ܗ‬੒৔ॴʹ͸૿෯ճ࿏͔ΒͷϏΞ͕৳ͼ͓ͯΓɼSTJ ͷԼ෦௒఻ಋମͱ૿෯ճ࿏෦෼͸ి‫ؾ‬తʹ઀৮͞
ΕΔɽճ࿏ͷ֤୺ࢠ͸ૉࢠද໘ʹΉ͖ग़͠ʹͳͬͨϘϯσΟϯάύουʹ઀ଓ͞Ε͓ͯΓɼ৴߸ͷಡΈग़͠౳͸͔ͦ͜Βߦ͏ɽSOI-STJ
Processing STJ directly on a SOI preamplifierboard to make the detector compact ,lownoise and easy to be multipixel detector.
SOI-STJ can be new novel detector! 	

Question• Is SOI caused any damage by processing STJ?
STJ processedon SOIຊ‫ڀݚ‬άϧʔϓͰ͸
SOI-STJ ͷ‫ڀݚ‬։ൃͷಋೖஈ֊ͱͯ͠ɼNb/Al-STJ ͱ SOIFET ͷΈ͔ΒͳΔSOI-STJΛ࡞੒͠ɼͦͷofSOIFETͱ STJ ͷಈ࡞֬ೝΛߦͬͨɽ͜ͷࢼ࡞Λ
SOI-STJ1
andschematicprototype	• Can Nb/Al-STJ be processed on SOI board ?	

3.5

SOI-STJ1ͱ‫͢ͱͱ͜Ϳݺ‬Δɽਤ 3.9 ʹ SOI-STJ1 ͷϨΠΞ΢τͱ౳Ձճ࿏Λࣔ͢ɽ1 ͭͷ 2.9×2.9mm ͷ

6

STJ processed on SOI board	
1 mA /DIV.	
2mV /DIV.	

apply magnetic
field

1 mA /DIV.	

IV curve of the STJ on SOI board 	

2mV /DIV.	

Leakage current : 6nA @0.5mV	150 Gauss

50uA /DIV.	
2mV /DIV.	

We can process goodSTJ on SOI board！
10 nA /DIV.	
500uV /DIV.	

Signal of Nb/Al-STJ processed on SOI board to465nm light	

We observed typical STJ signal
from STJ on SOI board！	

We confirmed STJ processed on
SOI board has no problem! 	

7

SOI-FET after processing STJ at Low Temperature	

W=1000um
L=1um	

Vgs[V]	

gm[S]	

Vgs[V]	

Vds[V]	

I-V curve of SOI-FETs after
processing Nb/Al-STJ.	

PMOS(750mK)	

-Ids[A]	

W=1000um
L=1um	

gm[S]	

Ids[A]	

NMOS(690~750mK)	

• Both of NMOS and PMOS
can be operated below 800mK.
• Trans-conductance “gm” isnot varied drastically for eachtemperature at operation
voltage(0.2V).	

SOI-FET with STJ processed
has excellent performance
below 800mK.	
Vds[V]	

SOI-FET is suitable for cold
preamplifier for STJ signal !	

8Summary	• We are developing STJ and SOI-STJ to detect single

far infrared photon for neutrino decay search.
• We confirmedü STJ processed on SOI board has sufficient quality.
ü SOI-FET has no damage by processing STJ
ü SOI-FET has excellent performance below 800mK.

9BUCK UP	

10

Temperature dependence of IV curve	!"#$"%&'(%")*"$"+,"+-")./)012)-(%3".+/&0+123(412*56&(70(8+5%6&3'(9$*(*+&(1*+&/(:/1:&/*7&0(5/&(52;10*($%8+5%6&3'#$%&'()*+ !",-d/WW͚ϭϰ!

11

Requirement for leakage current	!"#$%&"'"()*+,&*-"./.0"*1$&&"()*,+*2345-6789/+&%(01234%0212&5(64%78&(9+:*:%(4%;45&%*(*:(*+&(<=>?83@A#B(<$C=&2(:0(;2&1*&5(D$1643912*4;8&(4%(@A#(46(12:$%5(!""#E166$C4%7(F18(G(!-H'/&(I1%*(*:(6&9121*&(=&*I&&%(*+&(647%18(1%5(9&5&6*18(EJ(647C1H'(6:(2&D$42&C&%*(0:2(08$;*$1*4:%(:0(*+&(8&1K17&(;$22&%*(:0(@A#(46(0:88:I'ߜܰ‫ ݈݇ܽ݁ݍ‬ൌ ͵͵ 
L0(I&(166$C&(*+1*(4%*&721*4:%(I45*+(46(!'M($@B(:$2(2&D$42&C&%*(0:2(ƚŚĞůĞĂŬĂŐĞĐƵƌƌĞŶƚŝƐ͙ܰ‫ ݈݇ܽ݁ݍ‬ൌ ͳͲͺͻ ͳͲͺͻ ൈ ͳǤ͸ ൈ ͳͲିଵଽ‫ ݈݇ܽ݁ܫ‬ൌൌ ͳͲͺ ‫ܣ݌‬ି଺ͳǤͷ ൈ ͳͲ#$%&'()*+ ,-!.

d/WW͚ϭϰ12CIB Experiment for Neutrino Decay Search with JAXA Rocket
5 minutes DAQ at 200km height in 2016

Focal plane
Instruments

Preamplifiers(4K)Superconducting
Tunnel Junction(STJ) Detector Array(50 x 8 channels)

1.7K Cryostat>1W

Secondarymirror

Grating

Tertiarymirror

IR LightMain
Mirror
FPĳ
F=1m

120cm

Focal plane
Instruments

Liq-He tank Vibration
Post-Preamplifier
1.7K
DAQ system
Damper Star Sensor>1W
50cm
Weight 100kg

Nb/Al-STJ on newly designed chip	Division 1
100um×100um STJ array	

Division 2
STJs with dispersed junction	

Division 3

STJ array withdifferent sizes	

Division 5STJs with and without SiO2 	
To measure transmittanceof SiO2	

Division 4
STJs with different under layer sizes(Upper layer sizes are same )To measure dispersion of quasi particle