1. Low background facilities at LSM Pia Loaiza ILIAS meeting, Modane January 12 th 2005

2. Ge detectors at LSM DetectorTypeVolumeTotal and peak background rate (counts/day) 40-2700 keV352 keV583 keV1461 keV MONDEUSEwell220 cc7704.22.75 ROUSSETEwell430 cc6924.12.97.2 ABYMESwell980 cc8285.6 XXLwell844 cc8216.8<1.811.6 HERMINEN197 cc3131.21.52.3 HELLAZP204 cc5154.50.31.4 JASMINP380 cc5292.01.411.71 GENTIANEN215 cc178<0.210.380.65 IRISP400 cc2821.021.463.01 At present, the sensitivity are, typically, 1 mBq/kg for “reasonables” mass and measurement time. As S ~  /  BDF, Gentiane and IRIS have roughly the same sensitivity at 583 keV and 1461 keV.

3. On-going projects at the LSM Improvement of a low background Ge detector (IRIS, 400 cc). Prospective construction materials are being measured. Monte Carlo simulations are performed to get the distinct contribution to the background from the assembly materials and to determine the maximum acceptable radioactivities in order to get an improvement of a factor 5 in the detector background. We’ve found a high Th activity (0.13 Bq/kg @ 238 keV) in one of the insulators near the crystal, which need to be replaced by other material.

4. On-going projects at the LSM Cryogenerators : We plan to equip one Ge detector with a system of cryogenerators. Evaluation of possibilities of installation on one of our detectors is under way. Construction of a Radon precision measuring facility, with a sensitivity of ~ mBq/m3 (Vol. 70 l) New planar Ge detector : our needs regarding low-energy gamma detection require a new planar Ge (diam = 80 mm, d=35 mm), with a resolution of 0.7 keV at 50-60 keV. Performances of detectors in the market are being evaluated.

5. Radon trapping facility Installation September 2004

6. Radon trapping facility Time during which radon is trapped in the « filter » : T r = K(T) M / Q K(T) : dynamic adsorption coeff. M : charcoal mass Q : Air rate 2 charcoal towers : T 1 = -53  C, T 2 = -45  C M = 2 x 450 kg Vol. clean air : 150 m 3 /h Activity 222 Rn = 15 mBq/m 3 Radon purification by adsorption in charcoal