1. Low radioactivity at the Modane Underground Laboratory
Pia Loaiza
Laboratoire Souterrain de Modane, France
LRT 2004
12-13 Dec. 2004, Sudbury, Canada

2. LABORATOIRE SOUTERRAIN DE MODANE
Located in the French-Italian border,
under the Fréjus peak.
Depth : 1750 m of rock (4800 m.w.e)
French laboratory operated by
Commissariat à l’Energie Atomique and
Centre National de la Recherche Scientifique.
Entrance of the tunnel view from the office building.

3. LABORATOIRE SOUTERRAIN DE MODANE
4 muons/m2/day
fast neutrons/cm2/s from rock/concrete
radioactivity
Air continously renewed : 2 vol/hour
222Rn concentration 5-10 Bq/m3
Entrance to the Lab at the
mid-point of the
Fréjus road tunnel

4. PEOPLE AT LSM

5. EDELWEISS : Dark matter WIMP search
EDELWEISS II
French German collaboration
Start installation beginning 2005
Data taking: summer w. 28 detectors =>9 kg
Upgrade to 100 detectors 36 kg 2006
Dubna integration in progress
Neutron detectors w VETO m
EDELWEISS II
sensitivity goal
EDELWEISS I
exclusion limits present

6. NEMO 3 : Neutrinoless double beta decay
wood
coil
Iron shield
Water tank
NEMO 3 collaboration :
France, Czech Republic, USA,
Russia, Japan, Great Britain
May 2004
August 2001
Start taking data February 2003
May 2004 : Radon purification
system.
Tent surrounding the detector

7. Super Heavy elements In Nature
TGV-2 : CSNSM-Dubna
10 g of 48Ca for 2
10 g of 106Cd for ECEC
Sample
(Os-500 g)
3He-counters
Neutron
moderator
Super Heavy elements In Nature

8. Radon trapping facility
Installation September 2004

9. Radon trapping facility
Time during which radon is trapped
in the « filter » : Tr = K(T) M / Q
K(T) : dynamic adsorption coeff.
M : charcoal mass
Q : Air rate
2 charcoal towers :
T1 = -53 C, T2 = -45 C
M = 2 x 450 kg
Radon purification by adsorption in charcoal
Vol. clean air : 125 m3/h
Activity 222Rn = 15 mBq/m3

10. Ge detectors at LSM
13 germanium detectors to measure low radioactivity levels

11. Ge detectors at LSM Applications :
Test of materials for EDELWEISS, NEMO
and ultra low background instrumentation.
Measurement of environmental radioactivity Radionuclides in the U and Th decay series are useful chronometers for the determination of many processes in the environment. The low natural radioactivity encountered necessitate instrumentation capable of measuring very low radionuclide concentrations.
Some applications :
Quantitative evaluation of both horizontal and vertical mixing rates in the open ocean.
Determination of the rate of particle deposition on the marine sediment layer (originated by both biological and physical processes).
The decay of 210Pb provides a dating method which has been applied to lake sediments.

12. Monitoring of radioactive contamination in the atmosphere
Ge detectors at LSM
Applications :
Bordeaux wine dating
The concentration of 137Cs
provides a simple method to
estimate the wine age.
Monitoring of radioactive contamination in the atmosphere
Measurements of artificial radionuclides in certain
samples require very low backgrounds.
Those measurements are carried out at the LSM.
7Be and 137Cs concentration in the atmosphere

13. Ge detectors at LSM Detector Type Volume
Total and peak background rate (counts/day)
keV
352 keV
583 keV
1461 keV
MONDEUSE
well
220 cc
770
4.2
2.7 5
ROUSSETE
430 cc
692
4.1
2.9
7.2
ABYMES
980 cc
828
5.6
XXL
844 cc
821
6.8
<1.8
11.6
HERMINE N
197 cc
313
1.2
1.5
2.3
HELLAZ P
204 cc
515
4.5
0.5
1.4
JASMIN
380 cc
529
2.0
1.41
1.71
GENTIANE
215 cc
178
<0.21
0.38
0.65
IRIS
400 cc
282
1.02
1.46
3.01

14. ILIAS : Integrated Large Infrastructures for Astroparticle Science
ILIAS is an initiative proposed for funding by the European Union.
ILIAS
Physics in deep underground laboratories
R&D on low background techniques
Theoretical astroparticle physics
Gravitational wave detection
Transnational access
Network of deep underground science laboratories
R&D on double beta decay
Network of direct dark matter detection
Network of double beta decay

15. ILIAS at the LSM
Transnational access : Radon facility installed by Czech collaborators
Network : First meeting Sep. 2004, Edinburgh. Next meeting January 2005 at LSM.
Actual visits to the different labs will allow a better knowledge of working conditions
and specificities of the different sites.
R&D :
Construction of a new ultra-low background Ge detector (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.

16. ILIAS at the LSM
R&D :
Coordination of working package on RADIOPURITY OF MATERIALS.
First goal : database with measurements from experiments in the different labs.
The database will serve as a guide and will give benchmarks on attained
radioactivity levels. Measurement of all materials involved in any
low-background set-up are, nevertheless, necessary.
We plan to include in the database a clear reference to the material provider (and Ref. or lot number when available).
The aim in the longer term is to develop methods and techniques to obtain
materials extremely free from radioactive impurities.