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This report details the results and analysis of two experiments: TGV-1 (1994-2000) and TGV-2 (2000-Present), focusing on double beta decay of candidate nuclei. The TGV-2 experiment aims to improve detection capabilities and suppress low energy noise. Observed results, measurement quality, and comparison with theoretical predictions are discussed. The μCR42β experiment's setup and data analyses for muon capture rates for double beta decay is also provided, including observables measured, time evolution, and intensities of γ-radiation, as well as detailed analysis of intermediate and daughter nuclei. The status of the μCR42β experiment is highlighted.
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V. Egorov T G V Telescope Germanium Vertical status report JINR Dubna, Russia CSNSM Orsay, France CTU Prague, Czech Republic RRC - Kurchatov Institute Moscow, Russia CU Bratislava, Slovakia
Nuclei - candidates 0.187% 1.25% 2 X-rays $ 0.25 ×106/g
TGV-1 (1994 – 2000) results T1/2 (22) = =(2.97.5)•1019 y T1/2 (20) 1.5•1021 y (90%CL) Zero
Telescope Germanium Vertical (TGV-2) 32HPGeplanardetectors 60 mm × 6 mm with sensitive volume:20.4 cm2× 6 mm Total sensitive volume:~400 cm3 Total mass of detectors: ~3 kg Total area of samples :330 cm2 Total mass of samples :10 25 g Total efficiency :50 60 % E-resolution :3 4 keV@60Co LE-threshold :5 6keV Double EC (2005-2006): - 12 samples of 106Cd: 10 g 106Cd(~ 50 µm ) U+Th<0.1 ppb
Suppression of low energy noise with primitive Fourier analysis High freq. noise: E1 > E2 Real signal: E1 = E2 Low freq. noise: E1 < E2
Low frequency (microphonic)
GEMMA BTW: ν search for the Neutrino Magnetic Moment
µ [ 10–10 µB ] Low Energy Threshold [keV] ~ measurement quality
Results of one-year (2005) measurement 2νEC/EC (0+→0+,g.s.) decay of Cd-106 Experiment T1/2 ≥ 1.8 x 1020 y (95%CL) (TGV-2) T1/2 ≥ 5.8 x 1017 y (90%CL) (F.Danevich et.al.) T1/2 ≥ 1.5 x 1017 y (68%CL) (H.Kiel et.al.) Theory T1/2 = 1.0 x 1020 y (J.Suhonen) T1/2 = 8.7 x 1020 y (M.Hirsch) T1/2 = 4.4 x 1021 y (F.Simkovich)
-line 238 keV -line 352 keV Counts / day /detector Counts / day /detector
Gas-tight cup of the cryostat (ultra-pure Al, made by CANBERRA) has a weld seam here
Comparision of results 2νEC/EC (0+→0+,g.s.) decay of Cd-106 Experiment T1/2 ≥ 1.8 x 1020 y (95%CL) (TGV-2) T1/2 ≥ 5.8 x 1017 y (90%CL) (F.Danevich et.al.) T1/2 ≥ 1.5 x 1017 y (68%CL) (H.Kiel et.al.) Theory T1/2 = 1.0 x 1020 y (J.Suhonen) T1/2 = 8.7 x 1020 y (M.Hirsch) T1/2 = 4.4 x 1021 y (F.Simkovich)
CR42 Muon Capture Rates for Double Beta Decay ( PSI experiment R02-02 )
CR42 (d,2He) [PR C70(2004)] OMC ?
CR42 Ordinary Muon Capture (OMC) • Electron Capture: e- + (A,Z) (A, Z-1) + e Q~ me 0.5 MeV • Muon Capture: - + (A,Z) (A, Z-1) + Q~ m 100 MeV
CR42 OMC
CR42 Set-up
Observables measured: • -radiation energy (30 .. 8000 keV) • Time between the µ-Stop and the -emission (0 .. 1000 ns)
Time after the Muon Stop [ns] Energy of gamma-rays [keV]
Data Analysis: • Time evolution of the -lines intensity • Muon Life Time in the given isotope • µ-Capture Rate in the given isotope
CR42 Total -Capture Rates 48Ca 599±2 ns 40Ca 362±2 ns 48Ti 360±1 ns
Data Analysis: • Intensity of the -lines in the intermediate nucleus • Detailed balance of the -intensities • Partial µ-capture rates to the (1+), (2–) and other (low) excited states of the intermediate nucleus
CR42 OMC
Data Analysis: • Intensity of the -lines of the other daughter nuclei • Yield of the different daughter nuclei • Branching of the reactions: (µ,) (µ, n) (µ, 2n) (µ, p) … • Population of high-excited states in the intermediate nucleus
(Could be important for GERDA) BTW:µ– stopped in Argon Λcapture=(1.165±0.013) 1/µs