TG 11 overview /Material screening
Hardy SimgenMPI für Kernphysik
for Task Group 11
Outline
News on hardware: -spectrometers Gas counting systems and radon monitor
New results: Radon emanation measurements
→ Talk by Grzegorz Zuzel Radon behaviour in liquid nitrogen
→ Talk by Krzysztof Pelczar -ray screening results
Other news
News on hardware: LNGSGeMPI 3 + GeMPI 4
Both detectors suffer a 207Bi contamination from within the cryostat
GeMPI 4 cryostat was opened and thouroughly etched in July ’07
October ’07: 207Bi 10x lower, but still present
GeMPI III GeMPI IV - before clng. GeMPI IV - octoberE[keV] I [cts/d] [cts/d] [cts/d]40-2700 85.9 +-3.0569.7 97.7% 40.60 +-0.99 3.92 +-0.57 0.38 +-0.35
1063.7 74.5% 21.49 +-0.72 3.52 +-0.42 0.43 +-0.221633.4 0.0% 2.70 +-0.26 0.42 +-0.18 0.16 +-0.162614.5 35.6% 0.11 +-0.06 0.22 +-0.15583.2 30.4% -0.07 +-0.24 -0.05 +-0.19
1460.8 10.7% 1.51 +-0.43
News on hardware: LNGSGeMPI 3 + GeMPI 4
Nov 07: FET failure in GeMPI 4 (UPS problem?) has to be repaired
Future plans: GeMPI 3 + 4 will be brought to MPIK for
dismounting, electropolishing & replacing parts March / April 08
Refurbish Ge-diodes at Canberra Mounting cryostats @ MPIK June / July 08 ?
News on hardware: LNGSGATOR
New ultra-low background, 2.2 kg (100 % relative efficiency) HPGe-spectrometer at LNGS
End of 2007: FET broken Exchanged at Canberra Supposed to be
back at Gran Sassoin these days
News on hardware: MPIKLow-Level Laboratory (LLL)
Renovation of LLL completed end of 2007
News on hardware: MPIKGe-spectrometers
DAQ system re-started Muon-veto gas counters not yet running: Gas
supply system missing (→ this week) Corrado/Bruno: OK Dario:
LN2 cooling system broken: Detector was warm for months
Cryostat had to be removed from the shield for fixing
News on hardware: MPIKAdam
Recently refurbished borehole detector
Veto counters to be checked
News on hardware: MPIKGas counting system
Entering in the GERDA construction phase:
Need for 222Rn counting system at LNGS to check cryostat, cryogenic infrastructure, lock, …
Proposal: Re-use of GNO counting system Very low background Convenient location (in hall A)
Requires gas handling and proportional counter filling line at Gran Sasso.
System almost ready
After test at MPIK → shipping to LNGS in summer
News on hardware:LAr purification column for LArGe
Modification of support system and temperature sensors
Ready in April 08
News on hardware:Radon monitor
Expected to be ready in May 08.Not yet any experience with Ar.
-ray screening results: Recently investigated samples Lab Sample description Used for Mass [g]
LNGS PMT bases LArGe setup 1522
VM 2000 with glueLArGe setup / water tank
1233
Baksan HV feedthrough Suhner LArGe setup 211
Signal feedthrough 50-Suhner LArGe setup 320
IRMM Big capacitors 8200 pF LArGe setup 105
Small capacitors 4700 pF LArGe setup 31
Resistors 470 kΩ LArGe setup 49
Steel cableDetector string suspension
2290
Steel plates Transport chain 12383
Copper screws Matrix mounting 1062
-ray screening results: Electronics components
Samplespecific activity [Bq/kg]
228Th 228Ra 238U 226Ra 40K
HV feedthrough Suhner
0.23 0.02
0.51 0.04
35.7 0.4
Signal feed-through 50-Suhner
0.04 0.01
0.07 0.02
6.2 0.2
Big capacitors 8200 pF
1.0 0.1 1.3 0.1 0.4 0.15.2 0.3
5.7 0.42.5 0.2
Small capacitors 4700 pF
0.9 0.1 1.3 0.1 2.2 0.311.6 0.6
14.1 0.90.8 0.2
Resistors 470 kΩ0.20 0.02
0.13 0.03
0.4 0.20.28 0.03
0.6 0.10.2 0.1
-ray screening results: Suspension system
Samplespecific activity [mBq/kg]
228Th 226Ra 40K 60Co 137Cs
Steel plates 0.6 0.20.8 0.3
<3.71.2 0.4 13 1
Steel cable before cleaning
13.4 1.5
13.2 1.6
3600 200 172 9 2.8 0.6
Steel cable after cleaning1,2)
2.1 1.0 3.1 1.5 <9 200 12 <2
Cu screws <1 <1 <7 <0.5 <8
1) Activities somewhat overestimated due to slightly different MC geometry.2) Cleaning: a) Ultrasonic bath with soap, b) Rinsing with 2-propanol, c) Drying.
-ray screening results:PMT bases and VM 2000
Samplespecific activity [mBq/kg]
228Th 228Ra 238U 235U 226Ra 40KVM 2000 with glue
<1.2 <2.2 <39 <1 <1.6 140 10
PMT bases 14 18.3 1.4
650 80 33 4 <5.9 340 20
Other news
Paper on stainless steel screening almost ready for submission
Retirement of Wolfgang Hampel in summer 08 → no longer TG11 leader
Thanks to…
Laura Baudis
Joel Gasparro
Wolfgang Hampel
Mark Heisel
Mikael Hult
Jürgen Kiko
Matthias Laubenstein
Anatoly Smolnikov
…for providing input and slides.