Double beta decay and astroparticle projects in IEAP CTU ( NuPECC , Prague, 2011)

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Double beta decay and astroparticle projects in IEAP CTU ( NuPECC , Prague, 2011). I van Štekl Institute of Experimental and Applied Physics, CTU in Prague . List of projects : 1) TGV experiment – measurement of 2 n EC/EC decay of 106 Cd - PowerPoint PPT Presentation

Text of Double beta decay and astroparticle projects in IEAP CTU ( NuPECC , Prague, 2011)

Problematika pozad v experimentech subjadern fyziky

Double beta decay and astroparticle projects in IEAP CTU (NuPECC, Prague, 2011)List of projects:1) TGV experiment measurement of 2nEC/EC decay of 106Cd3) NEMO 3 experiment measurement of 0n and 2nbb decay of several isotopes4) SuperNEMO R&D, measurement of 0nbb decay of 82Se or 150Nd5) Pixel detectors in bb decay COBRA (CdTe), SPT (Si pixel det.)

5) PICASSO detection of dark matter

6) CZELTA detection of cosmic rays

Close cooperation with underground lab. LSM (France), LNGS (Italy), SNOLab (Canada)Ivan teklInstitute of Experimental and Applied Physics, CTU in Prague 1IEAP CTU was established 1. 5. 2002 by the CTU Rector as an educational and research institute of CTU oriented toward the physics of microworld and its applications (experimental base of CTU for the research in particle and subatomic physics being performed in international experiments). Research programme of the IEAP: (1) High energy physics and development of corresponding detection systems (CERN, Atlas experiment).(2) Neutron nuclear physics, physics of atomic nuclei, neutrino physics and astroparticle physics (JINR Dubna, French institutions, BNL, ILL Grenoble, TU Munich, University of Montreal and University of Alberta). (3) Applied nuclear spectroscopy and development of detection techniques. Medipix project (X ray and neutron radiography, imaging, tomography, ...). Radiation hardness of detectors. CIAA. Search for double electron capture in 106Cd (TGV collaboration) results utilization of Si pixel detectors JINR Dubna; IEAP CTU in Prague; CSNSM Orsay; Comenius university (Bratislava), Kurchatov institute (Moscow)

Since 2000, focus on 2nEC/EC decay of 106Cd

TGV-2Detectors: 32 HPGe 60 mm x 6 mmSensitive volume 20.4 cm2 x 6 mm Total sensitive volume ~ 400 cm3Total mass ~3 kg Double beta emitters: 16 samples (~ 50 m ) of 106Cd (enrich.75%) 13.6 g ~ 5.79 x 1022 atoms of 106Cd

Phase I Phase II EC/EC T1/2 (90%CL) T1/2 (90%CL) (0+0+,g.s.) 3.0 x 1020 yr 4.2 x 1020 yr (0+2+1,512) 4.2 x 1019 yr 1.2 x 1020 yr (0+0+1,1334) 3.1 x 1019 yr 1.0 x 1020 yr 0 res.(0+4+,2741) - 1.7 x 1020 yr 0 res.(0+ ?,2716) - 1.6 x 1020 yr

+/EC (0+0+,g.s.) 5.9 x 1019 yr 1.1 x 1020 yr (0+2+1,512) 5.9 x 1019 yr 1.1 x 1020 yr (0+0+1,1334) - 1.6 x 1020 yr

+ + (0+0+,g.s.) 6.0 x 1019 yr 1.4 x 1020 yr (0+2+1,512) 5.7 x 1019 yr 1.7 x 1020 yr

2+ + (0+0+,g.s.) - 1.3 x 1020 yr

(N.I.Rukhadze et al., Nucl.Phys. A 852 (2011)197-206)

How it compares with calculations

> 4.2 1020 p.w.approachingclosed 23 g of 106Cd with enrichment of 98.4 %Plans on near future Planned measurements with 106Cd:TGV-2 (Ge detectors) (~15 g) 600 cm3 HPGe detector (~8 g) (modes with g)SPT (Pixel detectors) (~8 g)

Approaches to double beta studiesSegmented CdTe pixel detectors (enriched Cd)Signature = two tracks of electrons from one pixel, Bragg curveParticle identification / rejection (alpha, electrons, photons)Si pixel detectors in coincidence modeThin foil of enriched isotopeSignature = two hitted pixels with X-rays of precise energy Efficiency (factor 2x comparing with TGV II)Particle identification (alpha, electrons)Pixel R&D projectsSetup based on semiconductor detectorsTGV IICOBRACUORESuperNEMOGERDADetector = sourceTracking + scintillatorLow-temp. detectorSemiconductor + segmentationCOBRA extensionSPT (EC/EC) Observable: 2 21keV X-rays from 106Pd daughter originated in the enriched Cd foilK1K2K1K2K1K1K2Double-side eventSingle-side events8Experiment NEMO-3 and SuperNEMONEMO experimentNeutrino Ettore Majorana Observatory netrinoless and two-neutrinos double beta decay, several isotopes - 100Mo, 82Se, 130Te, 116Cd, 96Zr, 48Ca, 150Nd

start of operation year 2003; from October 2004 with radon free air(tracking detector, calorimeter, 10 kg of isotopes, located in LSM)

end of operation January 2011 !!!!!!!!

SuperNEMO projectTracko-calo with 100 kg of 82Se or 150Nd3 years R&D program: improvement of energy resolution Increase of efficiency Background reduction .2010-2011: TDR2011: commissioning of first module in LSM (France) (2013 ready)2015: Full detector running Modules based on the NEMO3 principleMeasurements of energy sum, angular distributionand individual electron energyR&D funded by France, UK, Spain, Russia, Czech RepublicT > 2. 1026 yr < 0.05 0.11 eV(France, UK, Czech Republic, Russia, Spain, USA, Japan, Ukraine, Finland, Slovakia )100 kg 20 modules

Main activities of the IEAP staff for SuperNEMO:Rn measurements and R&D programmeUltra low background facility based on high volume HPGeTesting facilities of scintillating detectorsUltra low background facility based on high volume HPGe produced by Canberra, 600 cm3, detector is in LSM (from November 2010); FWHM (122 keV) = 1,13 keVFWHM (1,33 MeV) = 1,98 keVmeasured relative efficiency = 162%P/C ratio = 113installation in LSM January-March, 2011 (frame + Pb shielding = 23 kE).

Testing facilities of scintillating detectors prototype is ready in FMP ChU(mechanical part, electronic part, X-Y motion are ready; source of electrons with different energies was produced by JINR for us).

ENVINET company produces 140 scintillating blocks for X-wall + 40 Veto blocks of SuperNEMO demonstrator tracker (80 kE, financed by JINR + Czech Republic) => testing in Prague. schedule: April 2011 October 2011.

Left side = high Rn activity [activity Rn 38 kBq/m3 , dry air flow through Rn source 0.34 l/min], Right side =low Rn activity [background 73 events per day],Both sides are divided by testing foils. Long term measurements of Rn activities on both sides. Apparatus for measurement of radon diffusion

1/2 - Left/right vessel 3 - Radon source 4 - Flow-meter 5 - Sensors of temperature, humidity, and pressure 6 - Air dryer 7 - Air buffer 8 - Air pump, 0.5 l/miniMaterialThickness d [m]C1/C2C1/C2normalized to 15 mDiff. coefficient D [10-12 m2s-1]Diff. length L [m]HDPE (2 layers)21443.51.1193000EVOH*154.74.70.68570TROPAC III102>8300>600230089006.9358 261500 educational impact. At present, 7 running detection stations in CR, 1 in Slovakia, 1 in Romania (data are saved on common server, web interface).

We build the global network of detection stations on the Earth = huge telescope for detection of cosmic rays showers.

Detection station

HVPCScheme of the scintillating detector

U [V]t [ns]

channel 1channel 2channel 3 3 scintillators (60 x 60 x 1.5 cm) with photomultipliers in a triangle with a site ~10 m, work in a coincidence => detection of showers with the energy > 1014 eV. GPS for precise time-labeling of detected showers (precision ~16 ns) => it is possible to study space and time coincidence of the detected showers.Primary particleInteraction in the atmosphereShower of secondary particlesAnalysis of coincidence of distant showers - first results Data from 21 stations (ALTA+CZELTA) analysed. Double-coincidences on large distances No significant excess of coincidences. Bayes estimation of the event rate of the non-background coincidencies using data from all pairs of stations:

Tripple-coincidences on large distances

No significant excess Using the directions of showers will significantly reduce the statistical background.

f < 2.6 yr-1(c.l. 95%)

Dt We search for pairs of showers from different stations coming in a short time window. No information of direction of showers was used.23 CZELTA with other relative detection networks is the first really global network for the detection of high energy cosmic rays (all sub-networks use the same hardware, all data are available on-line from one web-page). Precise measurement of time => the project is designed for study of correlations of showers on very large distances. Secondary purpose of the project is to attract young students from high schools to physics, mathematics and computer sciences. We have good experience with these students after they come to Prague to study at a university they continue to work in our institute.Conclusion:

Broad involvement of IEAP CTU in underground physics (neutrino physics, dark matter)Detection of high energy cosmic raysDevelopment of detection technique (pixel detectors)International cooperation (France, Germany, Canada, Russia, Slovakia, )Responsibility of Czech team in experiments.

Thank you very much for your attention26SPT setup proposalEstimation of limit for EC/EC decay of 106Cd for 1 pair of Timepix quads:If background = 0 :

T1/2 > (e . t . Nat . ln2) / ln (1-CL) = 1,95 1020 years

90% CL ln (1-CL) = 2.3e ...... full efficiency (for SPT = 8,54 %)t ...... time of measurement [years], expected 4 yearsNat ... number of 106Cd atoms in foil, 98% of enrichment Nat = 1.89 1021 atoms

To reach limit of 1021 years:We would need 5-7 quad Timepix pairs in 1. prototype

(for 8 gr. we need 25-30 quad pairs)106Cd106Ag106Pd0+0+0+2+1133