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150 Nd Project

150 Nd Project. High Temperature Thermistors. Results on NdGaO 3. News about NdGaO 3. Neodymium Garnet. Scintillating Bolometers. Conclusions & Prospect. High temperature thermistors.

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150 Nd Project

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  1. 150Nd Project • High Temperature Thermistors • Results on NdGaO3 • News about NdGaO3 • Neodymium Garnet • Scintillating Bolometers • Conclusions & Prospect Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  2. High temperature thermistors Since the optimum operation temperature for the Nd bolometers is not predictable a priori, several NTD (Neutron Transmutation Doped) thermistors with different sensitivities and therefore optimized for different operation temperatures were prepared (thanks to the collaboration with E. Haller, LBL, and co-workers). Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  3. We wasn’t able to recognize Particle pulses We was able to see thermal injected power Down-conversions of ballistic phonons to thermal phonons is suppressed/trapped NdGaO3 We tested this compound several times during 2004 & 2005 We succeed to reach “low temperatures” (~ 17 mK) However the assembled bolometer showed a “strange” behavior Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  4. Phonon opacity….? Interaction between phonons and nuclear magnetic moments could explain this behavior. It is not easy to evaluate the mean free path of a ballistic phonon in the NdGaO3 crystal because the spin-phonon interaction depends crucially on fine-structure parameters that needs to be measured. The only way to avoid this interaction, and to effectively test the theory, is to eliminate in the crystal the isotopes with nuclear spins, i.e. 143Nd (12%) and 145Nd (8%) through a suitable enrichment in 150Nd. Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  5. 13x13x2 mm3 NdGaO3 (2.5 g) Heater Thermistor NdGaO3- thin sample The Idea is to try to evaluate roughly the enrichment needed to avoid this effect. We assembled a very small NdGaO3 bolometer by cutting the small sample Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  6. NdGaO3- thin sample-results 1 The detector is presently running @ LNGS After 3 weeks the temperature of the bolometer is ~ 13 mK The detector works as bolometer We are able to see ~ 70 keV of thermal injected power However……. Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  7. Heater pulse Particle Pulse  Structure ? 238U  710-7 g/g 232Th  310-8 g/g NdGaO3- thin sample-results 2 There are several classes of pulses The heater pulses are the fastest Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  8. No pulses are observed Neodymium garnet Neodymium garnet (Nd3Ga5O12) is somehow “similar” to neodymium gallate but easier to grow 18 mm height x 13 mm diameter Nd-Garnet The detector is presently running @ LNGS After 3 weeks the temperature of the bolometer is ~ 33 mK We will test a new Nd compound ( NaNd(MoO4)2 ) within the next run in the Hall C cryostat Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  9. Innovative Techniques Several tests were made in the R&D cryostat @LNGS during the lasts months The idea is to move towards a active background rejection Double readout heat - light 100Mo 3034 keV Nuclei with Q-Value above the 208Tl -  line 48Ca 4271 keV 116Cd 2802 keV Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  10. 6.6 cm dia 1 mm thick Ge 3x3x2 cm3 CdWO4 (140g) First “LARGE” mass high RESOLUTION scintillating bolometer for DBD A very impressive result was indeed obtained as a by-product. The idea was to measure the thermal neutrons flux inside the CUORE R&D cryostat using a CdWO4 crystal,via the (113Cd,n) reaction. Qbb(116Cd)=2802 keV Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  11. Mixing Chamber Stainless steel wire Light Detectors First damping mass (Roman Lead) Cuore Radioctivity test run (II Damping stage) Setup Very “un-clean” setup” Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  12. 0.9 % FWHM @ 2615 keV 3 % FWHM @ 2615 keV bb0n Calibration results 232Th + 56Co Calibration Heat Scitillation Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  13. Background measurement During April a background measurement was performed with the RAD detector The measure was optimized for the TeO2 crystals 417 h live time measurement arXiv:nucl-ex/0510074 Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  14. Actual Energy resolution At the end of the radioactive run we recognized that there were an error in the electronic setup of Cd We therefore performed a short calibration optimizing the CdWO4 bolometer. 0.24 % FWHM Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  15. Light Detector Preliminary results EFWHM LD =25 eV New Run 4x4x3 cm3 LiF Crystal ZnSe shows large Scintillation light 3x3x2 cm3 CdWO4 crystal 2 cm height 2 cm dia ZnSe crystal Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

  16. Conclusions • Neodimuim-based Detectors/Bolometers shows clearly the • difficulties of this compound • The Nd enrichment could be, maybe, not achievable within • the needed level • The “new” implementation of scintillating bolometers clearly • shows the easy feasibility of a “new” powerful experiment • Lot of effort is needed in order to identify a suitable scintillating • compound Stefano Pirro, IDEA Meeting -Zaragoza November 7 , 2005

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