1. Natural CMO+HPGe experiment
Sejong University
Kang Woon Gu
KIMS Collaboration

2. Motivation
1.HPGe detector at the Y2L(700m) has higher background than other
hpge detector by a factor of ~5-10.
2.This seems to be due to detector itself.
We need a new detector for ultra-low background measurement.
1400m
233m
IRMM
50 m
0 m
Depth
IRMM operates an underground laboratory at the premises of the Belgian Nuclear Research Centre in Mol, 233 m below the ground
Gransso
Fig.1

3. New HPGe detector Setup
Fig.3
Mass
Diameter
Height
2.8kg
79.9 mm
84.3 mm
Fig.2
Ortec mass = 2.424kg
Last year  replace an ortec hpge as a canberra hpge

4. B.G Rate with CANBERRA HPGe Detector
acrylic box open
in oder to LN2 re-fill
using data analyze
■U238 BackGround
Rn Gas effect
■Th232/K40 BackGround
Consistent
Fig.4
■ In last year, we measured bg levels for the new Canberra hpge detector
And this figure shows the measured results.
■ In the case of the U238 bg levels  were higher because of Radon Gas effect
■ But, in case of the Ra226 is lower than previous Ortec Ra226 bg level
■ In case of the Th232 and K40 bg level  were Consistent
■ In order to compare ortec bg levels, in the case of consistent dataanalyze

5. B.G Level with ORTEC and CANBERRA
U238 B.G level inconsisten 
Rn Gas effect
Fig.4
Good News
Ra226
Fig.5
Bi214
Ra226
Pb214
K40/Th232 Background Consistent
Tl208
K40
Tl208
Bi214
K40
Fig.7
Fig.6
■ In case of the Ra226 is lower than previous Ortec Ra226 bg level Good News
■The U238,Th232,K40 levels are, respectively, about 2 times and 5 times and about
8 times lower than previous Ortec bg level.(Fig.5,6,7)
■ In order to compare ortec bg levels, we was analyze using consistent bg level

6. HPGe B.G Energy Spectrum
Fig.9 P1
1.86evt/bin
Black Line : ORTEC  Hz
Red Line : Canberra Hz P1
5.08evt/bin
50keV~350keV P2
Fig.8
620keV~1200keV
Fig.10
0.219evt/bin P2
0.431evt/bin
■ In the case canberra spectra, the bg levels are lower than the previous ortec bg levels about two times.(Fig.8)
■ Also, in low energy region from 50keV to 350keV, the spectra show difference
between the results from the two detectors about 4 times maybe because of
difference in the detector qualities.(Fig.9)
■ We have interests mainly at this flat region from 620keV to 1200keV without bg peak.
in the flat region, the spectra are about 2 times lower than the ortec background.
Fig.10

7. Energy Resolution-DAQ Setup
Shaping Time = 6us
HPGe
Pre-Amp
Ge-E
ch0
Data
Acquisition
ORTEC
671
Amplifier
Ch1(1/3)
FADC400
ch2
Preamp Signal
■ Energy Resolution of HPGe detectord
□ We was replace an MCA card as a FADC-400MhZ
□ We want to confirm good energy resolution of HPGe Detector using a
400MHz fast-ADC(FADC) and ORTEC-671 Amplifier
■ Experiment DAQ setup
□ in the case of the ch0  from 0keV to 700keV
□ and, in the case of ch1  from 700keV to 3000keV
also, three times smalls than ch0 signal
Sigma*constant=area charge
■ UNI-Output singal – 671 Spectroscopy Amplifier
□ Front- and rear-panel BNC connectors provide positive, unipolar, shaped
pulses with a linear output range of 0 to +10 V

8. MCA-Card and Gammavision

9. ORTEC 671Amplifier Module
Front Panel
Rear Panel
Uni-Output signal
(1/3 signal)
700keV~3000keV
One input
Two output
PreAmp Input Signal
Uni-Output signal
(Normal Signal)

10. Signal Shape Ch0 – Amp671 Front Signal Ch1 – Amp671 Rear Signal
Ch2 – Preamp Signal
X-axis : Time [ns]
Y-axis : Height [mV]
Fig.11

11. Energy Resolution □ MCA card (G=20) ■ MCA card( G=10) Ba133
700keV
ch0
ch1
Ba133
Cs137
Co60
□ MCA card (G=20)
■ MCA card( G=10)
● FADC module(G=10)
Ba133
Fig.13
Fig.12
Cs137
Co60
Fig.14
Fig.15

12. 2E.C/EC β+ : Hamamtsu 3inch PMT Q-Value : HPGe detector
ECEC and EC/β+ of 92Mo
92Mo nucleus is double EC and beta plus EC isotope
Fig.16
In the Case of ECEC,Q-value is 1.65MeV for Mo92
2E.C/EC β+ : Hamamtsu 3inch PMT
Q-Value : HPGe detector
(A, Z) + 2e- -> (A, Z-2 ) keV(Q-value)
Abundance = 92Mo: 14.84%
We will perform a 2beta decay experiment for the
Mo92 using the new HPGe detector

13. DBD DAQ Setup
Pre-Amp
x100 in
CaMoO4 crystal
Signal
FADC400
Data
Acquisition
ch3
ECEC
HPGe
Detector
Q-Value
ch0
Pre-Amp in
F-Out
Ch1(1/3)
R-Out
Amp
ch2
This slide shows our DAQ setup for ECEC and EC b+ experiment using the HPGe detector and the CaMoO4 crystal

14. HPGe detector  Q-Value measured
DBD Experiment Setup
ECEC
CaMoO4 Crystal
HPGe
Detector
25X25X60 [mm]
Q-Value
25 X 25 X 215 [mm]
HPGe detector  Q-Value measured
3inch PMT  2EC/ECb+

15. Hamamatsu New PMT ■ 2EC/EC b+ signal measured
■ The R11065 are 76mm(3”) diameter head-on
PMT with extremely low radioactivity
■ photocathode area : Φ64mm
■ High QE and High cathode linearity
Response
Cathode Current Linearity

16. Plane & Summary ■ U238 bg levels inconsistent because Rn gas effect
■ but, the Th232 and K40 levels consistent
■ the bg levels of canberra hpge  lower than ortec bg
(U238,Th232,K40)
■ We was measured for good energy resolution using
400Mh FADC and amp671 module
■ We will performed a double beta decay experiment
using a CaMoO4 crystal and new HPGe detector

17. Backup Slide

18. U238 /Th232/ K40 Decay Chain Rn222 Up Rn222 Down Rn220 Down Rn220 Down
In csae of U238  Ra228 and Pb214, Bi214
In case of Th232  Ac228 and Pb212, Bi212 , Tl208