Development in MOON -- MOON-1 prototype detector status -- NOMACHI, - - PowerPoint PPT Presentation

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Development in MOON -- MOON-1 prototype detector status -- NOMACHI, - - PowerPoint PPT Presentation

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Development in MOON -- MOON-1 prototype detector status -- NOMACHI, Masaharu , Osaka University MOON collaboration 2005/SEP/18 HAW05 US-Japan MOON collaboration P.J.Doe, R.G.H.Robertson, D.E.Vilches, J.F.Wilkerson D. I. Will. CENPA,

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SLIDE 1

2005/SEP/18 HAW05 US-Japan

Development in MOON

  • - MOON-1 prototype detector status --

NOMACHI, Masaharu , Osaka University

MOON collaboration

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SLIDE 2

2005/SEP/18 HAW05 US-Japan

MOON collaboration

P.J.Doe, R.G.H.Robertson, D.E.Vilches, J.F.Wilkerson、

  • D. I. Will.

CENPA, Univ. Washington. H.Ejiri, T . I t a h a s h i , N . K u d

  • m

i , T . S h i m a R C N P

  • R. Hazama, K.Ichihara, S.Umehara, K.Matsuoka, H.Nakamura,

M.Nomachi, T. Ogama, T. Sakiuchi, Y.Sugaya and V.H.Hai Osaka Univ S.Yoshida Tohoku Univ S.R.Elliott, LANL J.Engel. Phys.Astronomy, Univ. North Carolina. M.Finger, and K. Kuroda, Phys. Charles Univ. Prague K.Fushimi, GAS, Tokushima Univ. Tokushima

  • M. Greenfield, ICU, Tokyo.

A.Gorin, I.Manouilov, A.Rjazantsev. High Energy Physics, Protvino.

  • A. Para FNAL
  • A. Sissakian, V. Kekelidze, V. Voronon, G. Shirkov A. Titov, JINR
  • V. Vatulin, V. Kutsalo, VNIIEF
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SLIDE 3

2005/SEP/18 HAW05 US-Japan

MOON Project

(Molybdenum Observatory Of Neutrino)

  • Object

The effective Majorana mass 50meV with ~ton of 100Mo.

  • Characteristic

– Source is separated from detector. It can be used 82Se, 150Nd, and others as well. –

100Mo

  • The large Q value of 100Mo is 3.034MeV.

100Mo has large phase space factor proportional to Qββ 5 for 0νββ.

  • 0νββ energy signal well above most BG(<3 MeV).
  • The natural abundance is large.

– Plastic scintillator(PL)

  • Purity of a PL is high.
  • Processing is easy to large scale.

Isotope Qββ (MeV) G0ν (10-14y-1) A (%)

48Ca

4.276 4.46 0.187

76Ge

2.039 0.44 7.8

82Se

2.992 1.89 9.2

100Mo

3.034 3.17 9.6

150Nd

3.368 13.4 5.6 G0n: phase space volume A: isotope abundance ratio

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SLIDE 4

2005/SEP/18 HAW05 US-Japan

MOON Detector

  • Multi layers module

–

100Mo foil & Plastic scintillator

Mo foil is interleaved with PLs. – Double layer hit To detect the double beta decay, two beta rays are detected by two PLs. – Active shield The other PL is used as active shield to reduce BGs. – Compact module PL works both as calorimeter and as active shield.

100Mo foil 100Mo foil

Active shield

100Mo foil

Active shield

100Mo foil 100Mo foil

β

Calorimeter

β

Calorimeter Active shield

100Mo foil

Active shield

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SLIDE 5

2005/SEP/18 HAW05 US-Japan

MOON

1.8m 1.8m 180 layer ~1.8 m

1.8m x 1.8m x 180 layer

9 module x 1.8m x 1.8m x 180 layer= 5250m2

100Mo 40mg/cm2

~2t

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SLIDE 6

2005/SEP/18 HAW05 US-Japan

Requirement on energy resolutuion

  • Photon Collection

To achieve the good energy resolution, photon collection efficiency should be high. MOON-1 detector is large coverage for sides

  • f a scintillator with many PMTs (about 80 %

surface of the four sides is covered.) 11.4%(FWHM) at 1MeV region.

  • Good Energy resolution

including the energy loss in the foil and a detector resolution. Good energy resolution is key to distinguish 0νββ from 2νββ.

[1] Nucl.Instrum.Meth.A536:79-122,2005

100Mo Foil: 6mg/cm2

Resolution: 7%(FWHM) T2ν= 0.8×1019y[1] T0ν> 0.8×1026y[1]

0νββ 2νββ

Sum energy(keV) Counts

9 6 7 k e V C

  • n

v e r s i

  • n

e l e c t r

  • n

s F r

  • m

2 7

B i c h e c k i n g s

  • u

r c e

F i g . t e s t s e t u p P L : 5 * 5 * 1 c m

3

3 2 P M T

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SLIDE 7

2005/SEP/18 HAW05 US-Japan

MOON-1 Detector

MOON prototype detector (MOON-1) was developed to study the energy resolution and BG rejection capability.

  • Plastic scintillator (PL), 6layers, 53x53x1cm3
  • BC408. equivalent .
  • 100Mo(94.5% enrich), 142g 40mg/cm2, 3layers

Mo foils are interleaved with two PLs. 2νββ is expected to ~3decay/year in the energy window 2.7-3.2 MeV region. (7% energy resolution is assumed) – Aluminized Mylar films are used to support Mo foil. and also, to suppress the cross talk of photon between PL layers.

  • 56 PMTs(40K Free 0.7Bq) are attached to PLs.

HAMAMATSU, R6236-01 K-MOD – Silicon cookie is used for the optical contact.

P L P L P L P L P L P L M

  • F
  • i

l M

  • F
  • i

l M

  • F
  • i

l

F i g . C r

  • s

s s e c t i

  • n

v i e w

  • f

M O O N

  • 1

P M T P L 5 3 * 5 3 * 1 c m

3

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SLIDE 8

2005/SEP/18 HAW05 US-Japan

PMT location

  • A PMT is attached to the 3

plastic scintillators.

  • The plastic scintillator,

which has energy deposit, is identified by PMT hit pattern.

P M T

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SLIDE 9

2005/SEP/18 HAW05 US-Japan

MOON-1 detector

M O O N P l a s t i c s c i n t i l l a t

  • r

5 3 * 5 3 * 1 c m

3

5 6 P M T s

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SLIDE 10

2005/SEP/18 HAW05 US-Japan

Oto underground Laboratory

MOON-1 detector has been working at Oto underground Laboratory since April/2005. This lab was used at ELEGANT-V experiment.

  • Depth

the lab is placed at 1,300m w.e.

  • BG level

The BG level were measured by ELEGANT group[2]. – Cosmic Ray: 4x10-7/cm2/sec – Neutron Flux:4x10-5/cm2/sec – Rn:10Bq/m3

[2] Nucl. Instr. and Meth. A459(2001)177-181

MOON-1 Osaka

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SLIDE 11

2005/SEP/18 HAW05 US-Japan

Experimental setup of MOON-1

MOON-1 is placed in active and passive shield.

  • NaI(Tl) detector

14 of NaI(Tl) detectors are put above and below MOON-1 detector. Those are used as gamma ray active shield

  • Air tight box

To keep Rn concentration low, N2 gas was flushing. Rn concentration was 125mBq/m3.

  • Lead & Copper passive shield

The outside of the air tight box is covered with 10cm Cu, 15cm Pb as passive shield.

P b P b P b P b C u C u C u C u

M O O N

  • 1

P l a s t i c s c i n t i l l a t

  • r

N a I 1 1 c m A i r t i g h t b

  • x

2 c m

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2005/SEP/18 HAW05 US-Japan

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SLIDE 13

2005/SEP/18 HAW05 US-Japan

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2005/SEP/18 HAW05 US-Japan

Analysis outline

  • Measurement

The first data of 11 days (live time 276 hours).

  • Trigger

Any hit at 2,3,4,5 layer is required for trigger. Trigger signal is made by summed signal of 8 PMT on four sides. The trigger threshold is 180 keV.

  • Analysis for one layer of Mo foil (51g)

1) Energy calibration 2) The double layer hit event selection 3) The sum energy spectrum for double layer hit events. 4) The remaining events

1 2 3 4 5 6

H i t l a y e r T r i g g e r P M T s F i g . t h e s c h e m a t i c v i e w

  • f

M O O N

  • 1
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SLIDE 15

2005/SEP/18 HAW05 US-Japan

Energy calibration

  • Energy calibration

Compton edge of 1.27MeV gamma-ray from 22Na source single layer events are selected.

  • Full energy peak

The sum of the energy deposits on plastic and NaI(Tl) may cause full energy peak.

  • MOON-1 energy resolution

The energy resolution is 15%(FWHM) for 1.27MeV full energy peak. The energy resolution of NaI(Tl) is 9%(FWHM) at 1.27MeV.

1.27MeV G a m m a

22Na

Compton edge 1.27MeV Gamma Full energy peak 511keV Gamma Full energy peak 1.27MeV+511keV Gamma Full energy peak

Deposit on single layer Deposit on single layer + NaI keV keV Counts Counts

2 2

N a s

  • u

r c e , 5 1 1 k e V , 1 . 2 7 M e V S e l e c t e d l a y e r

NaI

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SLIDE 16

2005/SEP/18 HAW05 US-Japan

Event selection by PMT hit pattern

  • PMTs are attached to plastic scintillators.

Each PMT is attaced to 3 plastic scintillators. Hit pattern of 12 PMTs are used for event selection

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2005/SEP/18 HAW05 US-Japan

Event selection by PMT hit pattern

  • Single layer Hit events

For the energy calibration, single layer hit events are selected.

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2005/SEP/18 HAW05 US-Japan

Event selection by PMT hit pattern

  • Single layer Hit events
  • Threshold Level -

Yellow PMT: 200keV Blue PMT: 200keV

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2005/SEP/18 HAW05 US-Japan

Event selection by PMT hit pattern

  • Double layer Hit events

Double beta decay events are the double layer hit.

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2005/SEP/18 HAW05 US-Japan

Event selection by PMT hit pattern

  • Double layer Hit events
  • Threshold Level -

Yellow PMT: 200keV Red PMT: 500keV Blue PMT: 200keV

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SLIDE 21

2005/SEP/18 HAW05 US-Japan

Double layer hit events

Sum energy spectrum

– the double layer hit events after 11 days of data collection – 51g 100Mo – NaI detectors are used for gamma-ray veto.

  • No event is observed at Q-value

(3MeV) region.

counts/50keV/year

1 1 d a y s m e a s u r e m e n t s D

  • u

b l e l a y e r h i t e v e n t s

4

K 1 . 4 6 M e Vγ D

  • u

b l e c

  • m

p t

  • n

s c a t t e r i n g

2 8

T l 2 . 6 M e Vγ D

  • u

b l e c

  • m

p t

  • n

s c a t t e r i n g MeV 1.0 2.0 3.0 0.5 1.5 2.5

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2005/SEP/18 HAW05 US-Japan

Remaining Events

  • 1. M.C simulation

– M.C. simulation for double Compton scattering – The gamma rays were generated at PMT. – The Normalizations are selected to be fit experimental data.

  • The shape of the spectrum

shows good agreement.

Data M.C. M.C. 40K M.C. 208Tl

4

K 1 . 4 6 M e V γ

2 8

T l 2 . 6 1 M e V γ MeV 1.0 2.0 3.0 0.5 1.5 2.5 counts/50keV/year

4

K , 1 . 4 6 M e V

  • r

2 8

T l 2 . 6 M e V

PMT S u m

  • e

n e r g y s p e c t r u m

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SLIDE 23

2005/SEP/18 HAW05 US-Japan

Remaining Events

  • 2. NaI active shield
  • The events are reduced to

about 50% by the gamma-ray veto.

  • The amount of the reduction is

consistent with the solid angle

  • f NaI detectors looking from

the MOON-1 detector.

MeV 1.0 2.0 3.0 0.5 1.5 2.5 counts/50keV/year

Without veto With veto S u m

  • e

n e r g y s p e c t r u m

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2005/SEP/18 HAW05 US-Japan

Remaining Events

MeV 1.0 2.0 3.0 0.5 1.5 2.5 counts

4

K 1 . 4 6 M e Vγ F u l l e n e r g y p e a k

2 8

T l 2 . 6 M e Vγ F u l l e n e g y p e a k

  • 3. Reconstructed

peak

  • This is the energy spectrum
  • btained by summing energy

deposits

  • n

two layers of plastic scintillator and

  • n

sodium iodide detector.

  • The full energy peaks for 40K

and 208Tl are reconstructed S u m e n e r g y ( P L s + N a I )

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SLIDE 25

2005/SEP/18 HAW05 US-Japan

Summary and perspective

  • MOON prototype (MOON-1) detector.

– Under the low BG environment, the measurement has been started since April/2005-

  • Analysis

– Energy calibration has been performed Compton scattering events. – Preliminary result of the energy spectrum of plastic and NaI shows 15%(FWHM) for 1.27MeV 22Na gamma ray. – Double layer hit events are selected. – Main component of remaining events in the sum energy spectrum is double Compton scattering events. – At 0νββ decay (3MeV) region for 11 days measurement, 100Mo 51g, no event is

  • bserved.
  • Perspective

We will continue the analysis, – Improve the energy resolution – Study the position resolution – Study the acceptance for double beta decay

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2005/SEP/18 HAW05 US-Japan

Position measurement

4 2 4 2 R R R R RatioX + − =

Ｒ 4 Ｒ 2 Ｒ 1 Ｒ 3

3 1 3 1 R R R R RatioY + − =

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SLIDE 27

2005/SEP/18 HAW05 US-Japan

Position dependence

P.E.

# of p.e.

) 1 (

2 2 2 2

            −       −       − × = L Y L X b L Y a L X a B

B :1860P.E. a : -0.0474 b : -0.001

Source Position Y(cm)

Red: X=0 Blue: X=18.6