Characterization of Large Characterization of Large CaMoO4 crystals for CaMoO4 crystals for

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Presented by H.J.Kim Presented by H.J.Kim

(KyungPook National U.) (KyungPook National U.)

2007/11/242007/11/24

22ndnd Korea-China Joint workshop Korea-China Joint workshop

Korea-China Workshop 2007, H.J.Kim

Double beta work status• Sn-124 excited state, Zn-64 study was Sn-124 excited state, Zn-64 study was

published in Nuclear Physics A 2007. published in Nuclear Physics A 2007. for Sn-124 with LSC physics draft is for Sn-124 with LSC physics draft is

in progress (NIMA published in 2007)in progress (NIMA published in 2007)• CaMoO4 study is on going :• Mo-92: EC+ study in 4 CsI(tl) shielding

+CaMoO4 background test (J.I.Lee’s talk) • SrCl2 : EC+ study in 4 CsI(tl) (J.So)• CeBr3 crystal development for EC+,

+, study (Gulrooh’s talk)• Sn-112 resonant 0n ECEC study with

HPGe

Sino-Korean Workshop 2006, H.J.Kim

CaMoOCaMoO4 4 Scintillation crystalsScintillation crystals

12.5 cm

2.2 cm

2.2

cm

Korea(2004) Korea(2004) Ukraina(2006)Ukraina(2006) Russia(2006)Russia(2006)

Russia(2007), ISTC ProjectRussia(2007), ISTC Project

H.J.Kim

History• CaMoO4 crystal R&D in very fast progressCaMoO4 crystal R&D in very fast progress

1) 2002 : Idea and try to grow CMO in Korea1) 2002 : Idea and try to grow CMO in Korea

2) 2003 : Discussion with V.Kornokov2) 2003 : Discussion with V.Kornokov

=> Send test CMO (better quality)=> Send test CMO (better quality)

3) 2004 : CMO characterizations and Conference 3) 2004 : CMO characterizations and Conference presentation presentation

Extended idea of XMoO4, low temp. CaMoO4Extended idea of XMoO4, low temp. CaMoO4

4) 2005-2007 : Large CMO with ISTC4) 2005-2007 : Large CMO with ISTC

5) 2006 : Discussion with F. Fanevich5) 2006 : Discussion with F. Fanevich

=> CMO by Lviv and collaborative effort => CMO by Lviv and collaborative effort

6) 2007 : CMO R&D in low temp. started by SNU 6) 2007 : CMO R&D in low temp. started by SNU groupgroup

7) ……….7) ……….

Korea-China Workshop 2007, H.J.Kim

Crystal used for testCrystal used for test

12.5 cm

2.2 cm

2.2

cm

S1S122x22x30mm22x22x30mmS0S010x10x10mm10x10x10mm

Large (L1)Large (L1)22x22x12522x22x125

XL1, 2XL1, 230x30x21030x30x210

38x20 mm38x20 mmUkraineUkraineUK2UK2UK3UK3

Russia Russia

Korea-China Workshop 2007, H.J.Kim

Clustering method with 400 Mhz Clustering method with 400 Mhz FADCFADC

The same method with Darkmatter Search The same method with Darkmatter Search

Total 42 s window with 34 s pulse window

# of Photoelectron/keV

& Absolute light yield

Korea-China Workshop 2007, H.J.Kim

# of PE with 60keV gamma

CdWo4 :197+-19S1 :28+-8UK2 :37.5+-8UK2 :41.9+-10

Korea-China Workshop 2007, H.J.Kim

Number of photoelectron from 60keV Number of photoelectron from 60keV

# of photoelecton from Am-241# of photoelecton from Am-241

Crystals tested 0.6-0.7PE/keV : Ukraine0.4-6PE/keV : Russia0.5PE/keV : Korea* The size of crystals are different

0.6 PE/keV => 6% FWHM at 3MeV (theoretical limit)

CaMoO4 small absolute light CaMoO4 small absolute light yieldyield

CaMoO4 S0 test• Na-22 source• Gain:100• peak time:12us• HV:1800V• Peak:520±116• e-h of CsI(Tl): 8.6±1%• 4300±500ph/MeV• Assume 15% QE,90%

eff 0.6 ± 0.1 PE/keV Need more study

CsI(Tl) reference test• Cs-137 source• Gain:20• Shaping time:4us• HV:1800V• Peak:1597±34.4• Pedestal:33±10• Resolution(FWHM): 4.9%• e-h pair = 37000.• NP = 37000/0.8/0.9 =

51000

* Tested with LLAPD (Details by M.J.Kim)

Korea-China Workshop 2007, H.J.Kim

Attenuation Length& Relative light output with S1 & XL1, XL2

Large size CaMoO4 test

- using two 3" PMT’s and attached at both end faces of CaMoO4 crystal.

- made small holes of few millimeter diameter at every 2cm distance in the teflon along the length wise direction of the crystal.

PMT1 PMT2

12.5 cm

2.2 cm

2.2

cm

Comparison between S1 and Comparison between S1 and L1 L1 CaMoOCaMoO44

Light yield of Big CMO/ Small CMO is 90%

Energy spectrum of Am-241- Placed the Am-241 radioactive source at every 2cm mark

Red= 2cm

Green= 4cm

Blue= 6cm

Pink= 8cm

Black= 10cm

Attenuation LengthAttenuation Length

2.0x100 4.0x100 6.0x100 8.0x100 1.0x101

10000

12000

14000

16000

18000

20000

22000

24000

26000

Mea

n

Distance(cm)

PMT1PMT2PMT1+PMT2

Attenuation Length = ~ 30 cmAttenuation Length = ~ 30 cm

Larger (XL1, XL2) CaMoO4 test

- XL1,XL2 crystals were used for test.- using one 3" PMT (green extended) and one 2"

PMT (bi-alkali) of CaMoO4 crystal.

- made small holes of few millimeter diameter at every 3cm distance

test with S1 & XL1, XL2 test with S1 & XL1, XL2

XL1 : ~of S1, XL2 : ~80% of S2

H.J.Kim

3” PMT side with Cs-137 3” PMT side with Cs-137

H.J.Kim

L1-CMOL1-CMO

0 2 4 6 8 10 12 14 16 18 208000

10000

12000

14000

16000

18000

20000

22000

Lig

ht o

utp

ut

Distance

PMT1 PMT2 PMT1+PMT2

H.J.Kim

L2-CMOL2-CMO

0 2 4 6 8 10 12 14 16 18 209000

100001100012000130001400015000160001700018000190002000021000220002300024000250002600027000

M

ean

Distancs(cm)

2"PMT 3"PMTsum

Korea-China Workshop 2007, H.J.Kim

Resoultion & light output comparison with S1 and UK2,UK3

H.J.Kim

Checking energy resolution with CdWO4

Energy resolution of 9%

H.J.Kim

Cs137 source with CMOs and CdWo4

H.J.Kim

Cs-137 with S1 and UK2, UK3

Relative light yield ; 1.2 : 1.9 : 2.0

H.J.Kim

Different fitting, different results

• The best way is subtract background from data and fold MC data with data with Gausian fit only

H.J.Kim

S1 with Gaussian+Exp

FWHM

H.J.Kim

Mean time distribution of CMOs

H.J.Kim

Summary

• Different size of CMO crystals from Different size of CMO crystals from Russia (ISTC project) and Ukraine are Russia (ISTC project) and Ukraine are being testedbeing tested

• # of photoelectron/keV, absolute light # of photoelectron/keV, absolute light yield and attenuation length are yield and attenuation length are measured measured

• Relative light output and energy Relative light output and energy resolution were compared. resolution were compared.

H.J.Kim

Work list before experiment

• Resolution and light yield issueResolution and light yield issue

->Different crystal results need to be resolved->Different crystal results need to be resolved

Test with the same size of LU3 and XL1Test with the same size of LU3 and XL1

Improve light output…Improve light output…

->Further study of LAAPD : LAAPD or PMT?->Further study of LAAPD : LAAPD or PMT?

-> How low temperature is necessary?-> How low temperature is necessary?

-> Size of CMO optimization -> Size of CMO optimization • Internal Background issueInternal Background issue

-> measurement UK3 (results) XL (soon…)-> measurement UK3 (results) XL (soon…)

=> Shielding optimization for VETO=> Shielding optimization for VETO• Enriched 100Mo, purification, growing issues • Low temp Det., • XMoo4 (X->?)

H.J.Kim

Backgrounds and signal for 20kg of CaMoO4 with 5 years data taking (GEANT4)

Mo-100 2Mo-100 2

Ca-48 2Ca-48 2

Tl-208Tl-208

Bi-214Bi-214

Signal (m=0.4eV)Signal (m=0.4eV)

Sensitivity 10kg (100Mo) 5% FWHM resolution 0.05 mBq/kg for 208Tl, 214Bi5 years 7.1x1024 y (90% CL)( 0.18~0.71 meV)

•Current best limit on 100Mo : 4.6x1023 by NEMO3 with 6.9kg 100Mo•Claim by Klapdor-Kleingrothaus et al. ~ 400 meV Assuming optimistic theoretical value

1010 significance significance

H.J.Kim

•Thank you

H.J.Kim

New Crystal for Am-241

DistanceMean of det00 (2” PMT) Mean of det01(3” PMT)

1 15390 10960

3 14880 109506 14740 109909 14630 1093012 14390 1061015 13880 1139818 15120 9494

Old Crystal for Am-241

DistanceMean of det00(2” PMT) Mean of det01(3” PMT)

1 12810 93703 11280 97856 10910 97849 10890 969512 10530 975715 9663 1046018 11790 8416

H.J.Kim

H.J.Kim

H.J.Kim