CryoScint'07

lundi 23 avr. 2007, 08:00 → 18:05 Europe/Paris

Institut de Physique Nucléaire de Lyon

Philippe Di Stefano (IPNL)

The Third Workshop on Cryogenic Scintillation will be held at Institut de Physique Nucléaire de Lyon on Monday April 23rd 2007. It follows two workshops organized at Oxford in 2004 and 2006. The workshop aims to provide a forum for discussion of latest results or work-in-progress in the field of scintillation down to milli-Kelvin temperatures. Possible subjects include: tests of new scintillators, luminescence mechanisms, low-background properties of scintillators, light detectors, modelling of light collection, and production/mass-production issues. Registration is free but mandatory by April 6th. Informal presentations are welcome but abstracts must be submitted by April 6th.

1 Welcome

Welcome

Orateur: Philippe Di Stefano

2 Double Beta Decay with double-readout bolometers

The key-features of the Heat+Scintillation light detection in the case of Double Beta Decay searches with bolometers will be presented. The new results obtained in the optimization of the ibryd detectors will be presented. Outline for the future tests will be discussed.

Orateur: Dr Stefano Pirro (INFN)

Slides CryoScint07_Pirro.ppt (Protégé)

3 Work at PSI

We dexcrive the status of our work at PSI.

Orateur: M. Johann Gironnet (IAS/PSI)

Slides CryoScint07_Gironnet.ppt

4 To be announced

TBA

Orateur: Irina Bavykina

Slides Cryoscint07_Bavykina.ppt

11:00 Coffee

5 Cryogenic Light Detectors with Neganov-Luke Amplification

Cryogenic Light Detectors with Neganov-Luke Amplification

Orateur: M. Christian Isaila (TU Muenchen)

Slides CryoScint07_Isaila.pdf

6 Monte-Carlo simulations of heavy inorganic scintillators

Cryogenic scintillator experiments are typically difficult to optimise by trial and error due to the difficulty of performing repetitive experiments at low temperatures. Monte-Carlo simulations are therefore an attractive option for optimising the light collection from cryogenic scintillators. The talk presents two of the most commonly used packages for the simulation of scintillators: Geant4 and Litrani. A difficulty in performing simulations is determining the input parameters such as the bulk properties (the intrinsic light yield, the scattering and absorption coefficients) and the surface properties. The MCRIM technique for determining the bulk properties is presented as well as AFM measurements of CaWO4 crystals in order to estimate surface properties. Results of simulations with CaWO4 are presented and compared with some published results.

Orateur: Dr David Wahl (Universidad Nacional de Ingeniería, Lima, Perú)

Slides CryoScint07_Wahl.ppt

12:30 Lunch

7 SciCryo update

Orateur: Philippe Di Stefano

Slides CryoScint07_DiStefano.pdf

8 Extension of the multi-photon counting technique for scintillator characterisation in the milli-kelvin temperature range

The multi-photon counting technique (NIMA, 553 (2005) 522) was essentially modified to investigate scintillation characteristics of crystals at milli-Kelvin temperatures using a 3He/4He dilution refrigerator. The temperature dependence of the scintillation decay time and light yield of CaWO4 were measured down to 20 mK for the first time. The scintillation light yield is found to be invariant below 10 K – a tenet crucial to a decade of cryogenic scintillator experiments, yet previously unproved. The temperature change of the decay kinetic of CaWO4 is analysed in terms of a simple three-level model of the emission centre. The model agrees well with the data over the temperature range (0.02-350 K) investigated, and is used to determine the parameters of the relaxed excited state.

Orateur: Dr Vitalii Mikhailik (Univ of Oxford)

Slides CryoScint07_Mikhailik.ppt

9 Report on the status of the ROSEBUD experiment

The ROSEBUD experiment has resumed its activity in the Laboratorio Subterráneo de Canfranc (LSC). A multi-target arrangement including three different scintillating bolometers, i.e. undoped sapphire (50 g), BGO (46 g) and LiF (33 g) has been mounted. We report on the discrimination of electronic vs. nuclear recoils achieved with each bolometer, as well as on the preliminary results on sensitivity.

Orateur: Mlle Lidia Torres

Slides CryoScint07_Torres.ppt

16:00 Coffee

10 Czochralski Growth of CaWO4 Crystals for the CRESST experiment

Czochralski Growth of CaWO4 Crystals for the CRESST experiment

Orateur: M. Christian Ciemniak (TU Muenchen)

Slides CryoScint07_Ciemniak.ppt

11 Discussion