1 / 22

CUORE: Cryogenic Underground Observatory for Rare Events

CUORE is a cryogenic underground observatory designed for the detection of rare events. It features cryogenic detectors with good energy resolution and a wide choice of detector materials. The observatory will be closely packed with 988 detectors made of TeO2, with a total mass of 741 kg. It aims to achieve high sensitivity and detect events above background noise at a given confidence level.

pgillis
Télécharger la présentation

CUORE: Cryogenic Underground Observatory for Rare Events

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CUORE:Cryogenic Underground Observatory for Rare Events Carlo Bucci INFN – Laboratori Nazionali del Gran Sasso on behalf of the CUORE collaboration LAUNCH, Heidelberg 21-23 March 2007

  2. Heat bath (~8 mK) Weak thermal coupling (G~4 pW/mK) Thermometer (NTD Ge , R~100 MΩ) Adsorber crystal (TeO2, C~10-9 J/K) Cryogenic Detectors Cryodet features ▲ wide choice of detector materials ▲ good energy resolution ▲ true calorimeters ▼ speed LAUNCH, Heidelberg 21-23 March 2007

  3. Measurement Time (y) Detector mass (kg) Efficiency Isotopic abundance 1/2 Energy resolution (keV) a M T S0n=ln 2 NA´ ´e A bG Atomic mass Background (counts/keV/kg/y) Unavoidable background sum electron energy / Q DDB-0n Sensitivity Sensitivity: Lifetime corresponding to the minimum number of detectable events above background at a given C.L. LAUNCH, Heidelberg 21-23 March 2007

  4. Isotopic abundance (%) Transition energy (MeV) 5 40 4 20 3 2 0 48Ca 76Ge 82Se 96Zr 100Mo 116Cd 130Te 136Xe 150Nd 48Ca 76Ge 82Se 96Zr 100Mo 116Cd 130Te 136Xe 150Nd TeO2 cryogenic detectors Active isotope 130Te ▲ high natural isotopic abundance: a =33.4 % ▲ transition energy: Q = 2530 keV ▲ reasonable nuclear matrix element calculations TeO2 Absorbers ▲ low specific heat ▲ large crystals available ▲ radiopure LAUNCH, Heidelberg 21-23 March 2007

  5. CUORE R&D (Hall C) Cuoricino (Hall A) CUORE (Hall A) CUORE @ LNGS LAUNCH, Heidelberg 21-23 March 2007

  6. Cryogenic Underground Observatory for Rare Events CUORE will be a closely packed array of988 detectors M =741 kgof TeO2 • Special cryostat & dilution unit • Cryogenic liquids free: 5 Pulse Tubes with …40W @ 45K & 1.5 W @ 4.2K • JT cycle instead of the 1K Pot • Dimensions: 1.6 m Ø x 3 m • (almost) all in Copper for radiopurity • huge mass to cooldown (mainly Pb shielding) • 1.5 ton @ 10mK • 6 ton @ 50 mK • 4 ton @ 600 mK • 5 ton between 40 & 4 K 80 cm 19 towers with 13 planes of 4 crystals each LAUNCH, Heidelberg 21-23 March 2007

  7. Pulse tubes 25 cm Pb 300 K 20 cm PET 4 K 50 mK 50 K 4He/3He Dilution Unit 600 mK 33 cm Pb shield (4 ton) 5 mK 3 cm Pb shield (3 ton) Cuore 3 cm Roman Pb shield (2 ton) 1600 CUORE cryostat LAUNCH, Heidelberg 21-23 March 2007

  8. CUORE Hut LAUNCH, Heidelberg 21-23 March 2007

  9. CUORE expected sensitivity In 5 years: Strumia A. and Vissani F. - hep-ph/0606054 LAUNCH, Heidelberg 21-23 March 2007

  10. Moore’s Law CUORE Cuoricino Mibeta 4 detectors array 340 g 73 g 1985 1990 1995 2000 2005 2010 2015 LAUNCH, Heidelberg 21-23 March 2007

  11. Cuoricino 11modules 4 detectors each Dimension:5x5x5 cm3 Mass:790 g Total mass 40.7 kg 2 modules 9 detectorseach, Dimension:3x3x6 cm3 Mass:330 g LAUNCH, Heidelberg 21-23 March 2007

  12. Detectors assembling All the operations done in Clean Room and nitrogen atmosphere LAUNCH, Heidelberg 21-23 March 2007

  13. Cuoricino module Ge NTD thermistor A Cuoricino module LAUNCH, Heidelberg 21-23 March 2007

  14. Tower assembling LAUNCH, Heidelberg 21-23 March 2007

  15. 2615 keV 208Tl single escape double escape 232Th Calibration Sum spectrum of all the 5x5x5 cm3 detectors DEFWHM =7.5 keV@2615 keV LAUNCH, Heidelberg 21-23 March 2007

  16. Live time Run I Cooldown: February 2003 Detectors: 14/62 detectors lost Working detectors: 73% Live Time: 23% • Upgrade: October 2003 • Wiring • DAQ • Temperature feedback • Cryogenics (20 years old cryostat) Run II Cooldown: May 2004 Detectors: 2 detectors still dead + 1 with high noise Working detectors: 95% Live Time: 60% (+ ~ 10% calibrations time) But many many hours lost due to high vibrational noise caused by the works underway in LNGS LAUNCH, Heidelberg 21-23 March 2007

  17. Background • Flat background above 2615 keV • Natural extrapolation below • Contribution to the 0n-DBD region: ~ 70%(degraded a from Copper & TeO2 surfaces) • In R&D already decreased by a factor ~ 4 LAUNCH, Heidelberg 21-23 March 2007

  18. 0n-DBD Background • Contribution from 232Th to DBD region ~ 30% • Internal shielding far from optimal (cryostat too small) • In CUORE should be much lower LAUNCH, Heidelberg 21-23 March 2007

  19. 0n-DBD peak @2530.3 keV 60Co sum peak Counts Energy [keV] * Dependent on the value for the nuclear matrix elements Cuoricino result on 130Te bb-0n decay Total statistic11.8 kg (130Te) × y b = 0.18 ± 0.01c/keV/kg/y Maximum Likelihood flat background + fit of 2505 peak Anticoincidence background spectrum the bb-0nregion LAUNCH, Heidelberg 21-23 March 2007

  20. KK-HM evidence (best value 0.44 eV) Cuoricino limit (with the same NME <0.41 eV) In 3 years running time t1/20nbb>5.2⋅1024y @ 90C.L. <mbb>< 0.12-0.64 eV Cuoricino result Strumia A. and Vissani F. - hep-ph/0606054 LAUNCH, Heidelberg 21-23 March 2007

  21. Cuoricino discovery potential <mn>=50 meV – half lives for different nuclei and models [1026 y] Elliot-Vogel 2002 Rodin et al. Suhonen et al. LAUNCH, Heidelberg 21-23 March 2007

  22. Conclusions • Cuoricino is presently the most sensitive DBD-0n running experiment, capable to hopefully confirm in a relatively short time the KK-HM “evidence”. • Cuoricino demonstrate the feasibility of a large scale bolometric detector with good energy resolution and background. • The costruction of CUORE, a second generation detector, is started and we plan to start taking data in less than 4 years from now. CUORE will have the capability to explore the inverse hierarchy mass region. LAUNCH, Heidelberg 21-23 March 2007

More Related