Double beta decay and astroparticle projects in IEAP CTU (NuPECC, Prague, 2011) List of projects: 1) TGV experiment – measurement of 2 EC/EC decay of 106 Cd 3) NEMO 3 experiment – measurement of 0 and 2  decay of several isotopes 4) SuperNEMO – R&D, measurement of 0  decay of 82 Se or 150 Nd 5) Pixel detectors in  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 Štekl Institute of Experimental and Applied Physics, CTU in Prague

IEAP CTU was established 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 106 Cd (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 2 EC/EC decay of 106 Cd

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

Phase I Phase II EC/EC T 1/2 ≥ …(90%CL) T 1/2 ≥ … (90%CL) (0 + →0 +,g.s.) 3.0 x yr 4.2 x yr (0 + →2 + 1,512) 4.2 x yr 1.2 x yr (0 + →0 + 1,1334) 3.1 x yr 1.0 x yr 0 res.(0 + →4 +,2741) x yr 0 res.(0 + → ?,2716) x yr β + /EC (0 + →0 +,g.s.) 5.9 x yr 1.1 x yr (0 + →2 + 1,512) 5.9 x yr 1.1 x yr (0 + →0 + 1,1334) x yr β + (0 + →0 +,g.s.) 6.0 x yr 1.4 x yr (0 + →2 + 1,512) 5.7 x yr 1.7 x yr 2 β + β +  (0 + →0 +,g.s.) x yr (N.I.Rukhadze et al., Nucl.Phys. A 852 (2011) )

How it compares with calculations > p.w. approaching closed

23 g of 106 Cd with enrichment of 98.4 % Plans on near future Planned measurements with 106 Cd: 1.TGV-2 (Ge detectors) ( ~15 g ) cm 3 HPGe detector ( ~8 g ) (modes with  ) 3.SPT (Pixel detectors) ( ~8 g )

Approaches to double beta studies Segmented CdTe pixel detectors (enriched Cd) Signature = two tracks of electrons from one pixel, Bragg curve Particle identification / rejection (alpha, electrons, photons) Si pixel detectors in coincidence mode Thin foil of enriched isotope Signature = two hitted pixels with X- rays of precise energy Efficiency (factor 2x comparing with TGV II) Particle identification (alpha, electrons) Pixel R&D projects Setup based on semiconductor detectors TGV II COBRACUORESuperNEMOGERDA Detector = source Tracking + scintillator Low-temp. detector Semiconductor + segmentation COBRA extensionSPT (EC/EC) Observable: 2× 21keV X-rays from 106 Pd daughter originated in the enriched Cd foil K1K1 K2K2 K1K1 K2K2 K1K1 K1K1 K2K2 Double-side eventSingle-side events

Experiment NEMO-3 and SuperNEMO NEMO experiment Neutrino Ettore Majorana Observatory - netrinoless and two-neutrinos double beta decay, several isotopes Mo, 82 Se, 130 Te, 116 Cd, 96 Zr, 48 Ca, 150 Nd - 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 project Tracko-calo with 100 kg of 82 Se or 150 Nd 3 years R&D program: improvement of energy resolution Increase of efficiency Background reduction …… : TDR 2011: commissioning of first module in LSM (France) (2013 ready) 2015: Full detector running Modules based on the NEMO3 principle Measurements of energy sum, angular distribution and individual electron energy R&D funded by France, UK, Spain, Russia, Czech Republic T ½ > 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: 1)Rn measurements and R&D programme 2)Ultra low background facility based on high volume HPGe 3)Testing facilities of scintillating detectors Ultra low background facility based on high volume HPGe – produced by Canberra, 600 cm 3, detector is in LSM (from November 2010); FWHM (122 keV) = 1,13 keVFWHM (1,33 MeV) = 1,98 keV measured relative efficiency = 162% P/C ratio = 113 installation 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/m 3, dry air flow through Rn source 0.34 l/min], Right side =low Rn activity [background 7±3 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/mini

Material Thickness d [µm] C 1 /C 2 normalized to 15 µm Diff. coefficient D [ m 2 s -1 ] Diff. length L [µm] HDPE (2 layers)2× EVOH* TROPAC III102>8300>600<0.0043<46 Mylar (2 layers)2×20>9100>2300<0.0012<24 EVOH (2 layers)2×15>31000>8900< <13 EVOH + PE Silicon RTV RTV ECOO STYCAST >7268>6.9<0.43<455 PET1 000>41 136>35<0.076<190 Acrylic glass Butyl Glue (6 µm) PE (11 µm) 17>9 985>8 261< <13 WB 50T Mylar junction TROPAC junction102>6300>500<0.0051<50

 Stainless steel box, inside 4x50L hemispheres made of wire net with PIN diodes  HV = 5-15 kV, airtight box flushing by measured air  Using 4x 50L detectors instead of one 200 L detector - hoping to increase the efficiency of radon detection.  Present status – measurement of background, calibration of efficiency.  Future plans – test in LSM. Apparatus for measurement of radon low activity (1mBq/m 3 ) – step to 1 m 3 detector 130 cm 70 cm

Emulsion of superheated freon (C 4 F 10 ) droplets embedded in a polymerized gel

Main activities of the IEAP staff for PICASSO: Rn measurements and suppression Low background measurements Construction of detectors containers (3. generation)

CZELTA CZEch Large-area Time coincidence Array – Czech Technical University in Prague – Silesian University in Opava, Czech Republic The hardware and the detection station design the same as is used in the ALTA experiment (Alberta Large-area Time coincidence Array, University of Alberta, Canada). 10 pieces produced in IEAP CTU. The sparse network for the detection of high energy cosmic rays (>10 14 eV). Stations are installed at roofs of high schools -> 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 HV PC Scheme of the scintillating detector U [V] t [ns] channel 1 channel 2 channel 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 > 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 particle Interaction in the atmosphere Shower of secondary particles

Analysis 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%) tt We search for pairs of showers from different stations coming in a short time window. No information of direction of showers was used.

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: 1)Broad involvement of IEAP CTU in underground physics (neutrino physics, dark matter) 2)Detection of high energy cosmic rays 3)Development of detection technique (pixel detectors) 4)International cooperation (France, Germany, Canada, Russia, Slovakia, …) 5)Responsibility of Czech team in experiments.

Thank you very much for your attention

SPT setup proposal Estimation of limit for EC/EC decay of 106 Cd for 1 pair of Timepix quads: If background = 0 : T 1/2 > (e. t. N at. ln2) / ln (1-CL) = 1,95 × years 90% CL  ln (1-CL) = 2.3 e full efficiency (for SPT = 8,54 %) t time of measurement [years], expected 4 years N at... number of 106 Cd atoms in foil, 98% of enrichment  N at = 1.89 × atoms To reach limit of years: We would need 5-7 quad Timepix pairs in 1. prototype (for 8 gr. we need quad pairs)

106 Cd 106 Ag 106 Pd   622 Q(EC/EC) = 2770 keV  % 1+1+  +  + /EC EC/EC 2νEC/EC 2KX Pd (~21 keV) (+  for e.s.) Main background: Cd KX-rays (~23 keV)  + /EC KXPd + 2  511 (+  for e.s.) νEC/EC KXPd + LXPd +  2741 (   512)  2229  2741  +  + 4  511 (+  for e.s.)  1046  νEC/EC 2KXPd + (    512) Decay modes + signatures

Schedule of TGV II experiment: (in Laboratoire Souterrain de Modane, France) Phase I ~ 10 g (12 samples) of 106 Cd (75%) T= 8687h (Feb.2005 – Feb.2006) Phase II ~ 13.6 g (16 samples) of 106 Cd (75%) T ~ 12900h (Dec.2007 – July 2009) Background I no samples (Aug.2009 – Mar.2010) Background II 16 samples of Cd.-nat (Apr.2009 – …2011)

KXPd KXCd ROI Phase II, 13.6g of 106 Cd, T=12900h

Type of interaction of ϰ with ordinary matter Two types: coherent (C) and spin dependent (SD) Coherent: σ(C) ~ A 2 >> for heavy nuclei (A > 50) Spin Dependent: σ(SD) ~ J(J + 1) λ 2 >> depending on λ and other factors (J is the nuclear spin, λ related to the magnetic moment of nucleus) Future could be: Bromotrifluoromethane Halon, BrF 3 C (A = 80)

Nucleus Jλ 2 J(J + 1) nf np ( 100GeV/c 2) 1 H 1/ F 1/ Na 3/ Al 5/ Cl 3/ Ge 9/ I 5/

Operation of SDD (Superheated Droplet Detector) Emulsion of superheated freon (C 4 F 10 ) droplets embedded in a polymerized gel Pressurizable detection module External piezo-electric sensors Holds an elastic polymer matrix that protects the superheated droplets Droplets mean size ~ 150  m PICASSO uses acoustical detection - piezo sensors - amplifiers - ADC’s - VME DAQ The recoiling nucleus triggers the phase transition Liquid droplet explodes and creates a gas bubble (First application by B. Hahn and S. Spadavecchia for detection of fission fragments  1960)

Outer box with temperature insulation Thermostat Heating cable Wooden box With scintillating detector Socket of 230 V (heating) Thin metal tube with cable 230 V Metal tube with other cables: - high voltage for photomultiplier - signal cables from photomultiplier - cable to testing LED diode - cable for controlling of thermostat GPS antenna Hardware of the detection station Meteorological station

PC UPS GPS receiver Crates Electronics

Web-based interface