P. Cermak Rez near Prague, December 2005

EC/EC process measurement in TGV

experiment

For TGV collaboration:

JINR Dubna, RussiaCTU Prague, Czech Republic

CSNSM Orsay, FranceRRC - Kurchatov Institute Moscow, Russia

CU Bratislava, Slovakia

P. ČermákIEAP CTU in Prague

P. Cermak Rez near Prague, December 2005

Outline

● TGV I TGV II● TGV II measurements overview● Data processing ● Example● Summary

P. Cermak Rez near Prague, December 2005

TGV

• Telescope Germanium Vertical (stack of 16 (32) HPGe detectors)

• aims at the study of double beta processes of 48Ca and 106Cd (double beta decay, double electron capture)

• started in 1996

• located in Modane Underground Laboratory (France)

P. Cermak Rez near Prague, December 2005

TGV I

yT 193.33.1

22/1 10)2.4(

● 16 HPGe detectors of planar type, diameter 40mm, thickness 6mm

● 8x 48Ca foils

● 8x Ca-natural foils

~ 1.35 x 1022 of 48Ca atoms (1.08 g)

)%90(105.1 2102/1 CLyT

P. Cermak Rez near Prague, December 2005

TGV I

open cryostat assembled cryostat, PAs

P. Cermak Rez near Prague, December 2005

TGV II

• to improve 48Ca result obtained

by TGV I

• to investigate processes in 106Cd

(to focus on EC/EC

channel)

),(22 10646

10648 raysXPdCde e

purpose:

2EC/EC:

keVEkeVkeV XECEC 2519:ROI,2778Q /

P. Cermak Rez near Prague, December 2005

TGV II spectrometer

Dewar

cryostatPbCu

borated polyethylene

PA

SM

1m

P. Cermak Rez near Prague, December 2005

Detector part of the TGV II

32 HPGe planar detectors 60 mm x 6 mm with sensitive volume: 20.4 cm2 x 6 mm Total sensitive volume: 400 cm3

Total mass of detectors: 3 kg Total area of samples : 330 cm2

Total mass of sample(s) : 10 25 g E-resolution : 3 4 keV @ 60Co LE-threshold : down to 10 keV Double beta emitters: - samples of 48Ca:

CaF2 + CH2 ( 75 mg / cm2 ) - samples of 106Cd:

106Cd (~ 50 µm )

U+Th<0.1 ppb

P. Cermak Rez near Prague, December 2005

TGV II

pedestal open cryostat

P. Cermak Rez near Prague, December 2005

TGV II

assembled cryostat, PAs

P. Cermak Rez near Prague, December 2005

Run overview

• 12/03 – 2/04… background, empty cryostat, 1363 hours• 3/04 – 5/04… 13x 106Cd + 3x Cd-nat., 1768 hours

113mCd,

14 years,

Q=590 keV

P. Cermak Rez near Prague, December 2005

● 5/04 – 6/04… 12x 106Cd + 4x Cd-nat., 328 hours● 6/04 – 10/04… 12x 106Cd + 4x Cd-nat., 2033 hours● 11/04 – 1/05… 16x Cd-nat., 903 hours● 2/05 – …… 12x 106Cd + 4x Cd-nat., new sources:

106Cd ... 75.00% 112Cd ... 6.18%108Cd ... 0.80% 113Cd ... 2.77%110Cd ... 4.47% 114Cd ... 6.18%111Cd ... 3.55% 116Cd ... 1.05%

Run overview (2)

P. Cermak Rez near Prague, December 2005

Data processing

1. What we look for: X-rays @21keV from 106Pd

P. Cermak Rez near Prague, December 2005

Data processing (2)2. What we have: X-rays @23keV from 106Cd

106Cd, 3736 hours

P. Cermak Rez near Prague, December 2005

3. Zoom to 20keV region (after background reduction)

3736 hours, 106Cd

Energy windows: (16-19) keV(19-22) keV(28-31) keV

5533 hours, 106Cd

P. Cermak Rez near Prague, December 2005

Summary

• Full configuration operation (32 channels)

• Background, calibration, admixtures in sources

• Basic background measurements done (empty cryostat, natural Cd)

• From February 2005 long-term measurement with 106Cd

• Negotiation on 106Cd lease extension

First direct measurement of EC/EC process in 106Cd (~ 6 x 1019 years)