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.