JRA2 - IDEA Integrated Double-beta

Transcription

1 JRA2 - IDEA Integrated Double-beta beta-decay European Activities Status of the activity Marisa Pedretti INFN Milano Bicocca and Insubria University (Como), Italy Outline Presentation of the IDEA tasks scientific issues advancements Conclusions 1

2 IDEA: presentation and role of the tasks The main purpose of this JRA is to promote key technologies in the experimental search for neutrinoless Double Beta Decay The experimental work is centred around three research sectors (working packages) which require substantial R&D activity: I: DBD isotope enrichment, to extend DBD investigation to new promising isotopes; P: Study of interesting candidate nuclides, such as 82 Se and 150 Nd, and in general high Q-value candidates. The main R&D objectives concern the purification of 82 Se and the realisation of innovative bolometric detectors containing high Q-value candidates. B: Advanced techniques for the diagnosis and the reduction of the radioactive background. An intense work with high technological content was performed for the rejection of surface radioactivity (with active and passive methods), of the cosmogenic activity (with simulation and experimental tests) and for the implementation of innovative shielding techniques (Ge diodes in purified liquid argon and nitrogen). 2

3 IDEA: presentation and role of the tasks B1 - Cosmogenic induced activity B2 - Underground crystal growth B3 - Rejection of surface radioactivity background control B4 - Ge diodes in liquid nitrogen sensitivity to M ββ ~ G 1/2 1 1 bδe M nucl (I.A.) 1/2 MT 1/4 P1-82 Se project P2-150 Nd project promising nuclides I1 - Isotope enrichment 3

4 IDEA: the tasks I1 - Isotope enrichment P1 82 Se project C. Marquet s talk Search on Double Beta Decay P2 150 Nd project B1 Cosmogenic induced activity B2 - Underground Crystal Growth B3 Rejection of surface radioactivity B4 Operation of Ge diodes in liquid nitrogen For each task I will: recall the objectives of the task describe the situation at the end of the last year describe the improvement obtained during this year (from march 2007) summarize the task situation 4

5 P2 150 Nd project 5

6 P2 150 Nd project: the physics case The activity of this task was initially dedicated to the development of Nd based bolometers as 150 Nd is potentially an excellent candidate for 0n-DBD search. η = < G(Q,Z) M nucl 2 > 1. much faster that any other nucides but new theoretical efforts are necessary 2. very high Q-value bolometric technique would be ideal for a high sensitive search F T Avignone III, G S King III and Yu G Zdesenko 6

7 P2 150 Nd project: the physics case The activity of this task was initially dedicated to the development of Nd based bolometers as 150 Nd is potentially an excellent candidate for 0n-DBD search. The results obtained have not been encouraging the activity of the task was re-planned Present objectives: use of the bolometric technique to study promising candidates for 0nDBD with high Q- value (as 150 Nd), such as 116 Cd (2802 kev), 100 Mo (3034 kev), 48 Ca (4871 kev) and 82 Se (2995 kev) develop of scintillating bolometers with crystals that contain the previous elements and present emission of scintillation light Participants: LNGS / Milano / Firenze 7

8 P2-150 Nd project: Realization and operation of large mass scintillating bolometers As regard the scintillating bolometers the idea is to combine the heat read-out with light read-out in order to control the alpha background τ=c/g ΔT=ΔE/C Not only the main bolometer but also the light bolometer have to be developed and optimized 8

9 P2-150 Nd project: Realization and operation of large mass scintillating bolometers As regard the scintillating bolometers the idea is to combine the heat read-out with light read-out in order to control the alpha background From IDEA Annual Report 2007: Test on scintillating bolometers have been done with the different crystals but the more promising results have been obtained with the following compounds: CaMoO4 crystal of 17.4 g (but high U and Th contamination) CdWO4 crystal 140g (very promising results) 9

10 P2-150 Nd project: Realization and operation of large mass scintillating bolometers New Results: CdWO4 A long Bkg measurement was performed with the CdWO4 scintillating bolometer 440 h live time measurement β/γ 0ν-DBD 116 Cd (2805 kev) α We succeed to work the detectors at 20 mk 10

11 P2-150 Nd project: Realization and operation of large mass scintillating bolometers New Results: CaF2 Measurement with a CaF2 bolometer of 86 g CaF 2 Sample (3x3x3 cm 3 ) 11

12 P2-150 Nd project: Realization and operation of large mass scintillating bolometers New Results: CaF2 Measurement with a CaF2 bolometer of 86 g Preliminary Results 12

13 P2-150 Nd project: Realization and operation of large mass scintillating bolometers New Results Other activities: a new CaF2 crystal of 450g have been achieved and will be measured in the next mounts a new ZeSe crystal of 120 g have been achieved and will be measured in the next mounts a new CaMoO4 crystal have been grown with clean powder and will be delivered at LNGS soon a new array of 4 crystals of CdWO4 has been assembled and will be measured in the next year The energy resolution of the Ge light detectors have been studied thanks to new dedicated 55 Fe source CaF 2 5 cm height 6 cm diameter 13

14 P2-150 Nd project: Realization and operation of large mass scintillating bolometers New Results Other activities: a new CaF2 crystal of 450g have been achieved and will be measured in the next mounts a new ZeSe crystal of 120 g have been achieved and will be measured in the next mounts a new CaMoO4 crystal have been grown with clean powder and will be delivered at LNGS soon a new array of 4 crystals of CdWO4 has been assembling and will be measured in the next year The energy resolution of the light detectors have been studied thanks to new dedicated 55 Fe source ΔE =

15 P2-150 Nd project: Realization and operation of large mass scintillating bolometers New Results Other activities: a new CaF2 crystal of 450g have been achieved and will be measured in the next mounts a new ZeSe crystal of 120 g have been achieved and will be measured in the next mounts a new CaMoO4 crystal have been grown with clean powder and will be delivered at LNGS soon a new array of 4 crystals of CdWO4 has been assembling and will be measured in the next year The energy resolution of the light detectors have been studied thanks to new dedicated 55 Fe source a work in order to obtain faster detectors is in progress. First results obtained imposing a feedback: heater on the crystal absorber whose power output is controlled by signal time evolution. Faster pulses and no change in the energy resolution. 15

16 P2-150 Nd project: Realization and operation of large mass scintillating bolometers Procurement of CaF 2, CaMoO 4, CdWO 4, ZnSe, CaMoO 4 crystals Several high T 0 thermistors available Detector working at higher temperatures and faster Ge light detectors tested with 55 Fe source 16

17 B1 Cosmogenic induced activity 17

18 B1 Cosmogenic induced activity: the physics case Exposure to cosmic rays can produce long-lived radioactive isotopes in set- up materials. This radioactive component can became a serious hazard for experiments looking for rare events like DBD experiments and can reduce the next generation experiment sensitivity. Example: 60 Co counts/kev 10 4 MC simulation β γ 1 γ 2 Q ββ Q ββ 76 Ge 130 Te γ1 + γ energy (MeV)

19 B1 Cosmogenic induced activity: overview coordinators: S. Cebrian (UNIZAR), M. Pavan (INFN) In the source=detector approach, an important part of the intrinsic background is due to cosmogenic activation of the detector Objectives : Development and upgrade of the cosmogenic activation codes New experiments based on irradiation of Ge and TeO 2 samples with high energy protons at accelerators Analysis of the irradiation results to check/upgrade activation codes Participants: Heidelberg / Milano / Zaragoza 19

20 B1 - Cosmogenic Induced Activity: new results Simulation-based work Codes: Monte Carlo Great efforts for systematic validation of hadronic models ongoing within GEANT4 collaboration with the aim to find or develop the best models in each kinematic range or use case. It is unrealistic to try to develop one super-model GEANT4 Review, CERN, April 2007 GEANT4 Hadronics Overview, A. Heikkinen Hadronic Physics Validation, D. Wright special ILIAS contributions at 12th GEANT4 Collaboration Workshop, September 2007, UK New models, some with good isotope production properties, are being incorporated in GEANT4 (INCL, ABLA) 20

21 B1 - Cosmogenic Induced Activity: new results Simulation-based work Codes: semiempirical People from University of Warwick (outside ILIAS) has released ACTIVIA code, based on semiempirical formulae + data tables for cross-sections IDEA reports used for comparisons 21

22 B1 - Cosmogenic Induced Activity: new calculations Estimate of the expected yield (excitation function) of some relevant long-lived products of NaI (check of predictions against measurements with exposed crystals at sea level ongoing) Cd Nd using MENDL libraries and YIELDX calculations. Estimates of activation: Cd 110Ag In some cases, discrepancies between different sources of data are not negligible. Therefore, neutron irradiation experiments to study isotope production in Cd and Nd are welcome. 22

23 B1 Cosmogenic induced activity p on a TeO 2, data analysis and final results on activation yields are being completed Experiment in design: p beams (CERN) of 1.4 and 24 GeV on Ge targets. MI group + US collaborators. Experiment running: n on Te at Los Alamos (WNR facility, GEANIE detector). MI group + US collaborators. Activation on Cu brick at exposed at 2000 m in Modane Natural activation on NaI detectors (ANAIS) Now activation test Collaboration with GEANT4: needs of underground community Study on Nd Zn Cd are in progress 23

24 B2 - Underground Crystal Growth 24

25 B2 Underground crystal growth: the physics case and overview coordinators: S. Capelli (INFN) - Julio Morales (UNIZAR) The most direct way to eliminate Cosmogenic Induced Activity is to grow crystals underground and in any case in radio-clean conditions Initial objectives: Crystallization of TeO 2 in radio-clean conditions, by eliminating radioactivity coming from crucibles and other elements (see 190 Pt problem) Feasibility study of underground Ge crystallization minimal exposition to c.r. Feasibility study of underground TeO 2 crystallization not necessary Participants: Milano / Zaragoza/IRMM 25

26 B2 - Underground Crystal Growth - status As the results from Cosmogenic Induced Activity Task indicate that TeO 2 crystals do not need to be grown underground, than the TeO 2 section program in this task was replanned. Therefore, the activity is now focussed on the development of a protocol for the production of extreme radio-pure TeO 2 crystals Four TeO 2 crystals with Czochralski method have been grown and bolometric array have been assembled and measured at the Gran Sasso National Laboratory. This test was planned to reduce the Pt contamination that are due to the fact that in Bridgman crystal grown technique Pt crucibles are used. data analysis shows that not encouraging results have been obtained (high 210 Pb contamination) In Nov 2006 a meeting in China with members of the TeO 2 crystals producer factory was done at the Shangai Institute of Ceramics CAS (SICCAS), in order to prepare a protocol for crystals production, polishing, storage and shipping and discuss crystals specifications and qualification procedure. 26

27 B2 - Underground Crystal Growth News: the protocol and the new 6 TeO 2 crystals protocol to produce extreme radiopure TeO 2 crystals at SICCAS (Bridgman technique) clear codification and check of all production phases purpose dedicated production unit, crystal growth facility and clean room, installed at producer 6 crystals have been produced in spring 2007, following the agreed protocol mechanical processing, previously performed at LNGS, have been implemented at producer new lapping powders have been selected, based on radiopurity requirements new polishing pad have been chosen. new drying and calcination procedures have been tested ICPMS measurements have been performed of the TeO 2 powders. 27

28 B2 - Underground Crystal Growth News: tests of new 6 TeO 2 crystals The set-up: - CUORE-like mounting system 3 planes 4-crystals each: 6 crystals grown and mechanically treated at producer following the new protocol 6 old style crystals (Cuoricino like growth and surface treatment performed at LNGS with the RAD procedure) 28

29 B2 - Underground Crystal Growth News: results of the new crystals test The new style crystals appear to have quite lower pulse amplitudes (despite the quite low working temperature) and poorer energy resolutions Detector Pulse Height FWHM [Low E] FWHM [2615keV] FWHM [5.4 MeV] μv/mev KeV KeV KeV BC1-T BC1-T BB2-T BB2-T BA1-T BA1-T BA2-T BA2-T BB1-T BB1-T BC2-T BC2-T B Old-style B Old-style 29

30 B2 - Underground Crystal Growth News: results of the new crystals test The new style crystals appear to have quite lower pulse amplitudes (despite the quite low working temperature) and poorer energy resolutions As regard the results on the background: - No evident improvement with respect to 190 Pt internal contamination (poor statistics doesn't allow to compare the different detector rates) - Higher rate in 4-5 MeV region with respect to RAD (similar rate with respect to Cuoricino) MeV structures could be ascribed to 238 U contamination both in crystals' bulk and surface. - Huge contamination in 210 Po ( it's usually observed for new crystals ) 30

31 B2 - Underground Crystal Growth News: results of the new crystals test Why these bad results: The crystals showed a strange yellow surface, probably attributable to the cleaning procedure: 1. the Al 2 O 3 powders have been selected for radiopurity reasons but, even if chosen with the same granularity of the chinese ones, didn't work properly: - large granularity powder is rather good though gives scratches - small granularity powder gives too many scratches and could not be used 2. the selected SiO 2 powder works extremely slow: - too small granularity -too soft - bad coupling with selected polishing pads (soft ) the bad surface could be the reason for the obtained bad performances and the high alpha background Modification of production protocol 31

32 B2 - Underground Crystal Growth News: test with new and re-lapped crystals A new run with 12 crystals with the following set-up: 4 new crystals, with Cuoricino-like growth and RAD-like surface treatment, completely done at producer (lapping with old Chinese powders + polishing with SiO 2 and old lapping pad) => to verify that the Chinese factory can guarantee a good and reproducible standard crystal production 6 of the presently tested New-style crystals but with RAD-like surface treatment at LNGS => to check if the bad performances are due to a surface problem 2 Old-style crystals (the two already used in this run) => for comparison Preliminary results on bolometric performances: The performances of these crystals after surface treatment with RAD procedure have improved and are comparable with the old style crystals. Not enough statistic to give background results. 32

33 B2 Underground crystal growth J. Morales S. Capelli Estimation performed. Severe 210 Pb contamination protocol to produce extreme radiopure TeO 2 crystals at SICCAS (Bridgman technique) clear codification and check of all production phases purpose dedicated production unit, crystal growth facility and clean room, installed at producer. 6 crystals have been produced in spring 2007, following the agreed protocol. mechanical processing, previously performed at LNGS, have been implemented at producer. new lapping powders have been selected, based on radiopurity requirements new polishing pad have been chosen. new drying and calcination procedures have been tested ICPMS measurements have been performed of the TeO 2 powders. after the results of measurements of the first 6 crystals the protocol have been changed and new 4 33 crystals have been produced. They are now running at LNGS

34 B3 Rejection of surface radioactivity 34

35 B3 Rejection of surface radioactivity: the physics case The background in CUORICINO is due to degraded alpha s and beta s which release only a part of their energy in the detector (surface contamination) TeO 2 TeO 2 Cu 214 Bi 208 Tl Cuoricino background 60 Co p.u. 35

36 B3 Rejection of surface radioactivity: overview coordinator: M. Pedretti In bolometric detectors, the radioactivity of the materials facing the crystals is presently the most dangerous contribution to the background Objectives : Implementation of various surface analysis methods Implementation of various surface cleaning procedures Realization of surface sensitive prototype bolometers (SSB) Development of CUORE-like modules with foreseen reduction of surface radioactivity by a factor between 10 and 100 with respect to present CUORICINO modules 36

37 B3 - Rejection of surface radioactivity: SSB + = Development of prototypes with active shields pulse shape analysis and comparison of signals between main and auxiliary bolometers identify the particles originated at the surfaces Prototypes also with different materials have been done during the previous years 37

38 B3 - Rejection of surface radioactivity: New test with TeO2 SSB Goal test of background reduction evaluation of the most suitable discrimination parameters Notes slabs: both active & passive due to cryogenic problems many readout channels were lost so we don t have a totally covered bolometer Active slabs Passive slabs 38

39 B3 - Rejection of surface radioactivity: New test with TeO2 SSB - Results DETECTOR Detector without slabs in the same run 0.16 ± ± 0.03 SSB (as passive) SSB (as active) 0.11 ± ± ± ± 0.02 RAD 0.06 ± ± 0.02 There could be many reasons to explain why we did not have an improvement of bkg level Possible answer: no clean slabs lost channels no total main detector coverage increase of the amount of Teflon (not covered by slabs) poor quality measurements PAY ATTENTION: WE ARE SPEAKING OF A VERY SMALL NUMBER OF PULSES New test with clean TeO2 slabs and full coverage is planned 39

40 B3 - Rejection of surface radioactivity: New surface sensitive detectors: NbSi film equipped bolometers NbSi film equipped bolometer with interdigitized electrodes crystal absorber 40

41 B3 - Rejection of surface radioactivity: New surface sensitive detectors: NbSi film equipped bolometers The FIRST prototype 2 cm A detailed discussion of set-up, measurements and experimental results in see Claudia Nones talk NbSi: 14x14 mm 2, thickness: 650 Å 500 Å of Ge amorphous under layer electrodes: 400 Å of Nb + 40 Å of Ir 41

42 B3 - Rejection of surface radioactivity: realization of passive shields of copper holder Test made by shielding the copper frame of bolometers with polyethylene film. A comparison of results obtained with the same detectors with and without the polyethylene film shows that in the interesting region (3-4 MeV) a reduction of background have been obtained without polyethylene with polyethylene 42

43 B3 - Rejection of surface radioactivity: realization of passive shields of copper holder Test made by shielding the copper frame of bolometers with polyethylene film. A comparison of results obtained with the same detectors with and without the polyethylene film shows that in the interesting region (3-4 MeV) a reduction of background have been obtained This is not a solution for a next generation experiment but an indication of the origin of background. We are making tests on coating of the copper frames with plastic materials 43

44 B3 - Rejection of surface radioactivity Polyethylene foils to shield the copper frame Tests on coating of the copper frames with plastic materials Implementation of a full cleaning procedure for copper Mechanical + Chemical + Electrolytic + Plasma (LNL INFN) Test on cleaned copper frame will start in April Test on ssb cuore-like prototypes are in progress New tests on surface sensitive bolometers with a new approach derived from the EDELWEISS collaboration 44

45 B4 Operation of Ge diodes in liquid nitrogen 45

46 B4 Operation of Ge diodes in liquid nitrogen: the physics case In experiments that use Ge diodes in order to searching for 0νDBD, LN2 and LAr can work at the same time as coolant and as shielding materials (passive and active) for the detectors Clean room lock Water tank / buffer/ muon veto Vacuum insulated copper vessel Liquid N/Ar Ge Array 46

47 B4 Operation of Ge diodes in liquid nitrogen: overview coordinator: S. Schoenert Initial objectives: Study of adsorption materials, especially for 222 Rn, 85 Kr and other potential contaminants like cosmogenic 7 Be. Upgrade of the potential of the existing nitrogen (gas) purification plant (which is housed in LNGS) in order to serve a large self-shielding liquid nitrogen tank Test operation of Ge diodes in purified nitrogen Extend to Argon the purification method Participants: Max Planck Institute, Heidelberg 47

48 B4 Operation of Ge diodes in liquid nitrogen: Status of activities Starting baseline: LN 2, option: LAr Adsorption has been chosen as purification technique Relatively cheap Successfully applied for 222 Rn removal (BOREXINO) Selection of materials for the purification of LN2 from trace amount of 222 Rn, 85 Kr and 39 Ar CarboAct was chosen (compromise: good adsorption properties for radon and krypton the price and the lowest radon emanation rate) Conceptual design of the nitrogen purification plant was presented C 0 C N gas V Ret H (α) V P Sample purif ication Mass spectr. liquid N L dewar with Kr-enriched ( ppt) liquid nitrogen LN 2, LAr 100/300-cm 3 column filled w ith adsorber bubbler 48

49 B4 Operation of Ge diodes in liquid nitrogen: NEWS on the activities Argon Purification Argon, originally as a backup solution, became the GERDA base line Scope of this task was extended to investigations of Argon purity and purification Only 222 Rn seems to be relevant. Allowed concentration at the level of 1 μbq/m 3 (Gerda Bkg ~ 10-4 c/kg/y/kev) Radon concentration measurements in different argon qualities have been performed the highest commercial purity contains the lowest radon activity (as expected) nitrogen is much purer in terms of radon Radon Reduction Factor have been measured in liquid and gas Ar 10 times bigger trap than 60 g-trap used in the liquid phase adsorption should be sufficient to stand 1 m 3 of LAr 49

50 B4 Operation of Ge diodes in liquid nitrogen: NEWS on the activities Argon Purification Conceptual design of the argon purification plant has been presented El. valve (Level cont.) Experiment Pump LAr Filter Flow/mass meter O 2 removal AC Filter El. valve (Level cont.) 50

51 B4 Operation of Ge diodes in liquid nitrogen: NEWS on the activities Argon Purification Argon, originally as a backup solution, became the GERDA base line Scope of this task was extended to investigations of Argon purity and purification Only 222 Rn seems to be relevant. Allowed concentration at the level of 1 μbq/m 3 (Gerda Bkg ~ 10-4 c/kg/y/kev) Radon concentration measurements in different argon qualities have been performed the highest commercial purity contains the lowest radon activity (as expected) nitrogen is much purer in terms of radon Radon Reduction Factor have been measured in liquid and gas Ar 10 times bigger trap than 60 g-trap used in the liquid phase adsorption should be sufficient to stand 1 m 3 of LAr Conceptual design of the argon purification plant have been presented more systematic investigations using traps containing up to ~500 g of CarboAct have been planed 51

52 B4 Operation of Ge diodes in liquid nitrogen: NEWS on the activities Argon Purification New adsorption column: Size: mm Volume: ~5 L CarboAct mass: 602 g 2 temperature sensors Pressure gauge Burst disc Cryo-valves Metal sealed (CF-100) 52

53 B4 Operation of Ge diodes in liquid nitrogen: NEWS on the activities Argon Purification New adsorption column: Test to verify that the Rn emanation from the new column (problem of re-contamination of gas): Column ready for tests and filled it with the activated carbon "CarboAct" - measurement of the intrinsic 222 Rn emanation rate of the column (including the activated carbon). 222 Rn emanation rate in saturation: ( ) mbq -CarboAct has an emanation rate of ( ) mbq/kg the housing and instrumentation contribution to the total 222Rn emanation rate of a such big column also contributes is remarkably small 53

54 B4 Operation of Ge diodes in liquid nitrogen: NEWS on the activities Test of the gas delivery path One can get pure gases on the experimental site by purification or by delivering product of requested quality Assuming that commercial companies can produce and deliver pure gases, it have to be demonstrated that it is possible to keep the initial purity in the entire delivery chain Measurements of Radon emanation from storage tanks have been performed (work in progress) in order to identify clean tanks in which LAr/LN2 can be stored without that 222 Rn emanated from walls will contaminate the liquid. Recent measurements: Tank from Quality of stored gas Vol. [m 3 ] 222 Rn activity in saturation [mbq] specific 222 Rn act. [mbq/m 3 ] Westfalen AG technical ± 6 59 ± 2 LINDE ± ± 0.1 Westfalen AG ± 2 63 ± 3 SOL ± ± 0.4 Air Liquide technical

55 B4 Operation of Ge diodes in liquid nitrogen Development of the argon purification plant. activated carbon CarboAct has been finally selected geometry of the column and the total mass of adsorption material has been determined the column has been tested and its Rn emanation rate is remarkably small test on radon emanation of cryogenic storage tanks have been performed 55

56 Meetings, scientific programs and web page Biannual general meetings Last meeting Paris - 19/20 Nov 2007 Next meeting Heidelberg - 29/30 Apr 2008 All presentations at the meeting can be downloaded from the WEB site 56

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59 Description of activation studies Te, Ge, and Cu chosen as targets of activation, due to their relevance in DBD experiments I. Evaluation of cosmogenic activation yields of relevant long-lived products in each of these three targets by nucleons at sea level following a common methodology: 1. To collect available information on isotope production cross sections, from measurements and from calculations (new or from libraries) 2. To choose the best description of the excitation functions of products (calculating deviation factors between measurements and different calculations) 3. To estimate the production rates of relevant products considering a particular cosmic ray spectrum and to compare them with previous estimates and/or measurements II. III. Simulation of some irradiation experiments with beams using both the semiempirical code YIELDX and the Monte Carlo package GEANT4 Global analysis of all activation studies (comparing calculations and simulations with all available experimental information) to conclude on codes 59

60 B1 - Experiment at CERN on TeO 2 Initial problem 1,E+02 COSMO predicted a high production cross section 1,E+01 of 60 Co in Te between 1-3 GeV 1,E+00 sigma (mb) 1,E-01 1,E-02 1,E-03 Disagreement with YIELDX calculations and measurement for 1.85 GeV p at Berkeley by Bardayan 97 1,E-04 1,E Co production in nat Te energy (MeV) Silberberg &Tsao (YIELDX) measurement Berkeley measurement CERN GEANT4 modified COSMO Irradiation experiment proposed and already carried out at CERN with 1.4 GeV p 60

61 Features of experiment B1 - Experiment at CERN on TeO 2 Beam (p) energy Fluence Sample mass Te mass 1.4 GeV p/cm g g Results Activation yields of many different products identified (Rb, Rh, Sn, In, Sb isotopes) and compared with YIELDX calculations 60 Co production cross sections (mb): energy (GeV) CERN Berkeley CERN YIELDX ± ± ± Sensitivity of CUORE to 130 Te DBD is not jeopardized by cosmogenic 60 Co in crystals and YIELDX calculations in good agreement with measurements 61

62 Plans for Ge irradiation with protons Beam irradiation experiment scheduled By Milano group together with American collaborators Ge samples Proton beams with energies 1.4 and 24 GeV At CERN Now, the highest energies available in measured production cross sections (p,x) in Ge are MeV This experiment will be very useful to validate high energy calculations. 62

63 Experiment on Cu Natural irradiation experiment By Modane group in JRA1 Sample: brick of Cu of 2250 g More than 3 months of exposure to cosmic rays at ~2000 m in Modane Gamma counting with HPGe detector underground just after irradiation Result: production rate of 60 Co R < 5 mbq/kg 63