The EDELWEISS-II experiment Silvia SCORZA Université Claude Bernard- Institut de Physique nucléaire de Lyon CEA-Saclay DAPNIA/DRECAM (FRANCE), CNRS/CRTBT Grenoble (FRANCE), CNRS/IN2P3/CSNSM Orsay (FRANCE), CNRS/IN2P3/IPN Lyon (FRANCE), CNRS/INSU/IAP Paris (FRANCE), CNRS-CEA/Laboratoire Souterrain de Modane (FRANCE), JINR Dubnia (RUSSIA), FZK/Universtat Karlsruhe (GERMANY)
12
Embed
The EDELWEISS-II experiment Silvia SCORZA Université Claude Bernard- Institut de Physique nucléaire de Lyon CEA-Saclay DAPNIA/DRECAM (FRANCE), CNRS/CRTBT.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The EDELWEISS-II experiment
Silvia SCORZAUniversité Claude Bernard- Institut de Physique nucléaire de Lyon
23*320g Ge/NTD : Developed by CEA Saclay and Canberra-Eurisys Amorphous Ge and Si sublayer: better charge collection for surface evts Optimized NTD size and homogeneous working T (16-18 mK) : goal keV resolution New holder and connectors (Teflon and copper only)
All @ LSM
Ge-NTD detectors
EDW-I rate: ~ 700 evts/kg/day for E>100keVAfter the most recent improvement EDW-II rate: ~ 300 evts/kg/day
EDW-I rate on central electrode : 2.5 - 5.5 evts/kg/day (400-
1000 /m2/day)EDW-II rate
~ 3 evts/kg/day
first low bg runs in 2006:
old bg
new bg
7*400g Ge/NbSi detectors :• developed by CSNSM Orsay• NbSi thin film thermometers for active surface evt rejection
2 @ LSM
Ge/NbSi detectorsidentification of surface events with Ge/NbSi detector
data taken with 1 NbSi detector May&June 2007: 1.5kg.d (fiducial)
200
150
100
50
0
806040200
x10-3
200
150
100
50
0
806040200
x10-3
Transient
Thermal
Heat signal of thermometer NbSiA :Surface eventBulk event
Thermometer Thermometer NbSiNbSiBB
Thermometer Thermometer NbSi NbSi AA Thermometer Thermometer NbSi NbSi AA
Thermometer Thermometer NbSiNbSiBB
Time (ms)
200
150
100
50
0
806040200
x10-3
200
150
100
50
0
806040200
x10-3
Transient
Thermal
Heat signal of thermometer NbSiA :Surface eventBulk event
Thermometer Thermometer NbSiNbSiBB
Thermometer Thermometer NbSi NbSi AA Thermometer Thermometer NbSi NbSi AA
Thermometer Thermometer NbSiNbSiBB
200
150
100
50
0
806040200
x10-3
200
150
100
50
0
806040200
x10-3
Transient
Thermal
Heat signal of thermometer NbSiA :Surface eventBulk event
Thermometer Thermometer NbSiNbSiBB
Thermometer Thermometer NbSi NbSi AA Thermometer Thermometer NbSi NbSi AA
Thermometer Thermometer NbSiNbSiBB
Time (ms)Rejection works, resolutions needs tuning
ID detector
Radius (cm)
Z (
cm
)
guard ‘g’: + 1V
guard ‘h’: - 1V
‘a’ electrodes: +2V ‘b’ electrodes:
+1V
‘c’ electrodes:-2V‘d’ electrodes: -1V
Electron trajectories
holetrajectories
‘a&c’ bulk event
‘a&b’ near- surface event
‘a,b&c’ event in low-field area
200g detector, concentric electrodes
2mm gaps, 200µm width
trigger thresh. 24keV241Am source with 60keV ´s
all eventsafter cut “b” < 5keV(30% of evts. survive)
recoil energy [keV] recoil energy [keV]
lab data
preliminary!
status ID bolometer
~1.7 kg.d
summary:first detector (200g) withinterleaved electrodes in LSM performance as expected
New 400g ID´s to be installedend of March
EDELWEISS-II next steps
Goal 2x10-8 pb (1200 kg.d no event) (~1 evt/kg/y)
acquire physics data with 23 NTD build 6 400 g NbSi
Goal 2x10-10 pb (~10 evt/t/y)
build 16 NbSi (same/tuned if needed) build 24 NTD with reduced contamination and/or with ID electrodes