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Zaragoza, 7.11.2005. JRA2 - IDEA. Andrea Giuliani. University of Insubria (Como) and INFN - Milano. I1 - Isotope enrichment. P1 - 82 Se project. promising nuclides. P2 - 150 Nd project. B1 - Cosmogenic induced activity. B2 - Underground crystal growth. background control.
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Zaragoza, 7.11.2005 JRA2 - IDEA Andrea Giuliani University of Insubria (Como) and INFN - Milano
I1 - Isotope enrichment • P1 - 82Se project promising nuclides • P2 - 150Nd project • B1 - Cosmogenic induced activity • B2 - Underground crystal growth background control • B3 - Rejection of surface radioactivity • B4 - Ge diodes in liquid nitrogen IDEA: presentation of the tasks
B2 – Underground crystal growth New contractor: IRMM
IRMM (Geel) New contractor UMICORE (Olen) Largest producer of Ge in the world CANBERRA (Olen) Company specialized in semiconductor detector development HADES (Mol) uderground lab (230 m of rock) steps for Ge detector realization: 1.reduction of GeO2 (10 ppb impurities) crystal growth 2. poly- and mono-zone refinement (1 and 0.01 ppb) 3.pulling (0.001 ppb) in principle, all the steps can be made underground 4.diode fabrication in practice, too expensive good alternative: minimize CR exposure between steps B2 – Ge crystal growth
HADES IRMM UMICOR ~ 10 km CANBERRA B2 – Ge crystal growth
Recent effort to study the possibility of replacing Bridgman method (SICCAS) with Czochralski method (CTI, IPI) get rid of Pt impurities from the crucible (190Pt is radioactive) A 3x3x3 cm crystal procured from CTI company The crystal was operated as a detector for two runs in Gran Sasso (Hall C refrigerator - R&D for DBD bolometers) The technical bolometric performance was excellent High surface radioactivity not possible to set meaningful limits on the bulk impurities (U, Th, Pt) B2 – TeO2 crystal growth 4 detectors from CTI with final CUORE size will be ready in Feb 2006 They will be operated in a clean environment after surface treatment
B2 - R&D Contract between LLNL and CTI Important stimulus from IDEA: - visit to CTI company and preliminary agreement - discussion on crystallization procedure - purchase of a 3x3x3 cm3 crystal • Phase 1 : Redesign of CTI furnace to grow 75 mm diameter TeO2 crystals (completed) • Phase 2: Production of one TeO2 crystal large enough for 5x5x5 cm cube (target date: 30/9 – 31/12) • Phase 3: Delivery of 4 each 5x5x5 cm finished TeO2 crystals (target date: 31/12/05 – 31/3/06) • Phase 4 : Successful test of 5x5x5 cm TeO2 crystals as bolometers at LNGS (within 10 weeks of delivery)
B2 - SICCAS (Shanghai) option • Need to work with them to develop clean procedures for crystal production • clean materials • strict procedures • clean room operation • Visit planned for Nov. 14 • prepared list of topics to be discussed • tour new production facility