* ** ** ** ** *** ****

**** ***** ***** ***** * ******

* ** ** **

** *** **** ********* ***** *****

* ******

(Received October 2, 2017)

We have designed a far-infrared pulsed light source to evaluate and calibrate superconducting

tunnel junction (STJ) detectors that we are developing to search for radiative decay of neutrinos and measure the energy of those decay photons. Those photons are predicted to be in the far-infrared region of wavelength 50 - 90 m. Measurement of this photon energy makes it possible to determine the unknown neutrino mass. This paper describes the pulsed light source we designed to reproduce the photons in the same wavelength range as expected for neutrino-decay photons.

Neutrino mass, Neutrino-decay photon, Superconducting tunnel junction detector, Far-infrared molecular laser, Far-infrared pulsed light source

* **

*** ****

***** ******

* Graduate School of Pure and Applied Sciences, Univ. of Tsukuba

** Applied Physics Course, Graduate School of Engineering *** Research Center for Development of Far-Infrared Region

**** Faculty of Engineering, Chubu Univ. ***** Faculty of Pure and Applied Sciences, Univ. of Tsukuba

****** Faculty of Science and Engineering, Kindai Univ.

[1] 1998

[2]

3

1福井大学 大学院工学研究科 研究報告 第66巻2017年10月Mem. Grad. Eng. Univ. Fukui, Vol. 66（October 2017）

1

Weak Boson WL WR

Left-Right Symmetric Model1017

[3]

[3] 2

[4]

[4]

110 /cm3

1.9 K0.6 meV

95%

[5]

[5]

0 71 meV 9 72 meV 50 87 meV

14 24 meV50 90 m 3 6 THz

Cosmic Background Neutrino Decay Search (COBAND)[6],[7] ,

Superconducting Tunnel Junction STJ2

23.1 meV 0.34 meV 0.04 meV

14 24 meV1

1

2 STJ

2

STJ 2

STJ

50 90 m

STJ

Nb/Al STJ465 nm3 [8]

50 90 m

[9] 4CO2 1

CH3OH CH3OD

40 500 m 2.5 meV31 meV 70

40120 m 1 [9]

1 CO2

CO2 9 11 m 90

657.2 m

118.8 m

4

3 465 nm 60 psNb/Al STJ

3

1 40 120 m CO2

( m) (meV)a)

b) c)

d)

(mW) ( m)e)

(W)41.4 30.0 CD3OH 10R(18) 10.26042.6 29.2 CD3OH || 9R(28) 9.23043.7 28.4 CD3OH || 10R(18) 10.26044.0 28.2 CH2DOH || 9P(30) 9.63947.6 26.1 CH3OD || 9R(8) 9.34252.9 23.5 CD3OH 4.2 9R(34) 9.201 5755.6 22.3 CD3OH 9R(28) 9.23057.2 21.7 CH3OD 72 9R(8) 9.342 7361.6 20.2 CH3OH 9R(18) 9.28263.0 19.7 CH3OH || 10R(16) 10.27467.2 18.5 NH3 || 9R(30) 9.22070.5 17.6 CH3OH 9P(34) 9.67677.3 16.1 CH3OH || 9R(8) 9.34277.3 16.1 NH3 || 10R(14) 10.28981.6 15.2 CD3OH || 10R(16) 10.27486.4 14.4 CD3OH 10R(16) 10.27496.5 12.9 CH3OH || 9R(10) 9.329

102.0 12.2 CH2DOH 9P(16) 9.520103.1 12.0 CH3OD 9P(30) 9.639105.5 11.8 CH2F2 || 9P(16) 9.520108.8 11.4 CH2DOH || 9P(12) 9.488109.3 11.4 CH2F2 || 9P(24) 9.586112.5 11.0 CH2DOH || 9P(12) 9.488117.2 10.6 CH3OD || 9P(26) 9.604117.7 10.6 CH2F2

9R(20) 9.271118.8 10.5 CH3OH 38 9P(36) 9.695 76

a) Db) CO2 || CO2

c)

d)

e)

118.8 m

5

CO2

1CO2

CO2

CO2

5

5 118.8 m

4

STJ

1

STJ

STJ3

2.5

42

ABCD[10]

118.8 m

6 = 3.43 mm

7353 rad/s

6 ( )

7 353 rad/s

5

839 mm 47 mm

57.2 m26 50% 4 m

0.5% [11]

1

8750mm

1SBD

ns

1118.8 μm

8

8

SBD

SBD

=

353 rad/sSBD

=

8 1

100

= 1 s

6

SBD

8 = 860 mm = 27

SBD 50 mSBD

50 m

8

4.1 mm

6.6 0.6 mm

4.5 s 7.2 0.7 s

SBD 5.7 0.4 s

9

9

,

7

50 90 m57.2 m

30

STJ

(2) (2) 1084 mm

2.0 mm 1 mm2.5 0.1 mm

0.1 mm (2)

1.7 3.1 s2.0 3.8 s

10

911

10 Scitec Instruments 310CD

11

,

8

100/s

270 /s

11

57.2 m

11

111978 mm

0.29 mm0.41 mm

2 mm 0.14 mm

0.1 mm(3)

1.4 4.1 s 1.4 5.8 s

9

1978 mm3537 mm

1930W. E.

26

STJ

[1] 68-11, 723 (2013). [2] Y. Fukuda .: Phys. Lett., 81, 1562 (1998). [3] Shin-Hong Kim .: J. Phys. Soc. Jpn., 81, 024101

(2012).

9

[4] S. p.160 (2013).

[5] C. Patrignani .: Chin. Phys. C, 40, 100001 (2016). [6] Shin-Hong Kim .: Physics Procedia, 37, 667

(2012). [7] Shin-Hong Kim .: JPS Conf. Proc., 1, 013127

(2014). [8] 71

22aAN-6 2016 3 22 . [9] , , J. Plasma Fusion

Res., 87-12, 801 (2011) . [10] Bahaa E. A. Saleh, Malvin Carl Teich

p.84 (2009).

[11] 15

10