112007 Radon Emanation Measurements H Simgen G Zuzel MPIK Heidelberg brPage 2br Gerda General Meeting IRMM Geel 1113062007 Outlook 222 Rn emanation and detection Investigated samples Kalrez gaskets Oxygen adsorbers Steel plates with ID: 82306
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GerdaGeneral Meeting, LNGS Italy, 5-7.11.2007 Radon Emanation Measurements H. Simgen, G. ZuzelMPI-K Heidelberg GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Outlook 222Rn emanation and detection Investigated samples-Kalrezgaskets-Oxygen adsorbers-Steel plates with welds-Cryogenic valves-Magnetic arm-Habiacable-KF-16 gaskets226Ra in the water Future plans GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 222Rn detection Töpler pumpPusher Hg diff.pumpP10Ar Charcoal trap for He purificationwith flowmeter He Getter pump Molecular sieve trapSi-GetrapChromo-sorb trapRadon transporttrap NaOHtrap To the pumpTo the bubbler Counter flange Main line Pressure gauge Absolute detection limit 30 100 µBq (15 50 atoms) GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 222Rn emanation Raemanation rate (226Ra activity seen via 222Rn emanation) GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Kalrezgaskets 4 x 2621791 x 330502 GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Kalrezgaskets -results 0.02 0.07 0.01 0.01 0.27 0.39 0.22 0.16Em. rate/gasket [mBq] V #5 0.05 4 254213 V #6 0.04 4 262179 Big chamber 0.27 0.06 1 327259 V #4 0.06 0.03 3 + 1 327260 + 327262 V #1 0.26 0.06 4 327607 Small chamber 1.54 0.10 2 + 2 330500 + 330501 Big chamber, (90 Bq) 1.29 0.07 6 330502 Small chamber; (50 Bq) 0.64 0.05 4 317483RemarksTotal emanation rate [mBq]AmountArt. Number GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Kalrezgaskets expected signal 0.032542130.40330500 0.13327607 0.022621790.271 3272590.223305020.16317483Total emanation rate [mBq]AmountArt. Number SS££0.6 mBqAllowed emanation from all sources in the cryostat: ~30 mBq(0.5 Bq/min Ar(STP) 10-4c/kg/keV/y) GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Oxygen adsorbers OxisorbcartridgeTrigonRoom temp.46.4 2.3498 24~100 g93 gMassRoom temp.1.9 0.1~19MESSER, small cartridgeOxisorbAt 150 C46.2 4.0496 42Metal oxides on alumina support (Alumina: 80-90 %, Copper oxide: 10-14 %)Gespec: ~1 Bq/kg U/ThTrigonCommentsEmanation rate [mBq]Spec. emanation rate [mBq/kg]DescriptionAdsorber GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Stainless steel plates welded as foreseen for the GERDA cryostat Steel plates with welds 0.10.36 0.04Emanation rate [mBq/m]Total surface (both sides): ~0.4 mWeld length: ~0.8 mTotal surface (both sides): 1.5 mWeld length: 2.53 mDescriptionAfter 2-hour etching (20 %*)HNO+ 1.7 % HF + water) and 30-min passivation(15 % HNO+ water).Not much gas in the Rnsamples2 platesStandard workshop cleaning procedure (alkaline bath), optically clean.A lot of gas in the Rnsamples7 platesCommentsSample *)by weight, procedure suggested by the BAMA companySurface not treated at all10 Bq/m4.6 Bq/mTotal surface (both sides): 71 mStainless steel tapeSurface washed with distilled water Estimated emanation rate inside the cryostat: mBqRn 2 1001.0 ´ Allowed activity in the cryostat: ~30 mBq(0.5 Bq/min Ar(STP) 10-4c/kg/keV/y) GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Cryogenic valves -WEKA O-ringgasket 222Rn source 222Rn source:A = 150 mBq C ~ 1 kBq/m 50TRCH 1000 36PCTFEOriginal gasket 1278 14TeflonCommentsDiffusion rate [mmBq]Emanation rate [mmBq]Stamp gasket GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Cryogenic valves -KAMMER NPT / VCR connections Full metal sealed 34 54VCR ½Teflon sealed79 24NPTCommentsDiffusion rate [mmBq]Emanation rate [mmBq]Connection 222Rn source:A = 150 mBq C ~ 1 kBq/m GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Cryogenic valves -WTA KammprofilgasketTeflongaskets 0.64 0.15Closed2.0 0.2OpenEmanation rate [mBq]Valve status GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Magnetic arm Ra= (0.11 0.05) mBqMagnetic arms will be installed in the lock. GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Habiacoaxial cable Sample mass: 514 gMeasured emanation rate:(0.34 0.09) mBq/kg GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 KF-16 O-rings 0.537 0.028165 g50 piecesVitonO-rings(bright green)0.680 0.021144 g50 piecesVitonO-rings (green)0.017 0.00386 g49 piecesPerbunanO-rings (black)Emanation rate [mBq/piece]AmountSample GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 226Ra in water samples 6.5 2.619.1 4.1Ra concentration[mBq/mAfter the Millipore-ELIX and Advantage purification systems (18.2 MAfter the Millipore-ELIX purification system (11 MDescription62-L sample measured in the big emanation chamberPurest water13-L sample measured in the small emanation chamberDe-ionized waterCommentsSample 0.8Reverse osmosis, de-ionization, 226Ra adsorption(18.2 MDouble distillation in a quartz apparatus (only a few liters per day)Samples measured using STRAW at GS.BorexinowaterSamples investigated using the small and big emanation chamberQuartz-distilled water Other samples for comparison: GerdaGeneral Meeting, IRMM Geel, 11-13.06.2007 Plans Emanation of the cryostat (at SIMIC, without copper, before final cleaning) Emanation of the cryostat after cleaning and copper shield assembly (GS) Further samples: Kammprofil gaskets, WTA valve with indium seals, steel plates with welds after electropolishing,