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Stefano Pirro, IDEA Meeting –Milano November 10 2006 Status of the scintillating bolometer program Scintillating Bolometers Background rejection capabilities.

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Presentation on theme: "Stefano Pirro, IDEA Meeting –Milano November 10 2006 Status of the scintillating bolometer program Scintillating Bolometers Background rejection capabilities."— Presentation transcript:

1 Stefano Pirro, IDEA Meeting –Milano November Status of the scintillating bolometer program Scintillating Bolometers Background rejection capabilities Interesting Compounds Future Prospects First tests

2 Stefano Pirro, IDEA Meeting –Milano November Some remarks The activity of this task was initially dedicated to the development of Nd based bolometers. Unfortunately the results obtained in the first 2 years were not encouraging Therefore the activity of the task was re-planned (since April 2006) but keeping the spirit of the task: the use of the bolometric technique in order to study promising candidates for neutrinoless double beta decay with high Q-value (as 150 Nd), such as 116 Cd and 100 Mo

3 Stefano Pirro, IDEA Meeting –Milano November Principles of operation Thanks to the different Quenching Factor ,  / , and neutrons can be easily identified  =C/G  T=  E/C

4 Stefano Pirro, IDEA Meeting –Milano November Environmental “underground” Background Background rejection capabilities I CUORICINO Background 130 Te 76 Ge 100 Mo 116 Cd (External Contaminations)

5 Stefano Pirro, IDEA Meeting –Milano November Background rejection capabilities II (Internal Contaminations) Thanks to Bi-Po’s and Beatles internal contaminations do not play a significant role BI-Po Bi-Tl BEATLE Does not hold for 234 Pa (Q=2195 keV)

6 Stefano Pirro, IDEA Meeting –Milano November Our Setup - I 3x3x2 cm 3 CdWO 4 (140g) 6.3 cm dia 1 mm thick Ge Q  ( 116 Cd)=2802 keV

7 Stefano Pirro, IDEA Meeting –Milano November Our Setup - II 17 g CaMoO cm diam 3 cm height CaF 2 3x3x2 cm 3 CdWO 4 Light detector

8 Stefano Pirro, IDEA Meeting –Milano November Calibration results on CdWO 4 0.2% 2615 keV2.9 % 2615 keV 232 Th + 56 Co Calibration Heat Scitillation 2.9% FWHM is the best result ever achieved with CdWO 4 as scintillator

9 Stefano Pirro, IDEA Meeting –Milano November Background measurement on CdWO 4 During last year a long Bg measurement was performed with the RAD detector The measure was optimized for the TeO 2 crystals 440 h live time measurement

10 Stefano Pirro, IDEA Meeting –Milano November CdWO 4 - some considerations

11 Stefano Pirro, IDEA Meeting –Milano November CdWO 4 - some considerations II E-rotated  E rotaded =Heat cos  + Light sin  2615 improves by ~ 40 % !!!!!

12 Stefano Pirro, IDEA Meeting –Milano November Light Signal [au] CaMoO g sample 147 Sm (ext) 238 U 226 Ra 210 Po 222 Rn 224 Ra 214 Bi- 214 Po (  +  /  ) 218 Po --

13 Stefano Pirro, IDEA Meeting –Milano November Contaminations Both series of 238 U and 232 Th are observed, but both of them are broken at Radium 238 U series 238 U 7.6  0.8 mBq/kg (0.61  0.06) g/g 226 Ra 107  3 mBq/kg (0.86  0.02) g/g ** (broken series) 232 Th series 232 Th 0.17  0.12 mBq/kg (4.2  3) g/g 228 Ra 4.6  0.6 mBq/kg(1.13  0.14) g/g** (broken series) **(equivalent to parent in case of secular equilibrium)

14 Stefano Pirro, IDEA Meeting –Milano November Future developments CdWO 4 crystals are good (apart 113 Cd) and extremely radiopure We plan to make a “pilot experiment” with an array of 4 crystals within Regarding Mo is more complicated…. Molybdates crystal are not so developed Molybdates crystal are not so clean We found a different CaMoO 4 supplier and we have a new large sample (97 g) From HPGE measurements we know that the radiopurity is a factor 3.3 better with Tespect to the 17.4 g sample This new crystal will be tested in the next CUORE R&D run This kind of research is funded by INFN for , OUTSIDE (parallel to) CUORE


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