1. Silvia Borjabad Copper Electroforming 7th JRA-1 Meeting Zaragoza (November 2007) Status Report

2. OUTLINE  Copper Electroforming Process  Review of objectives and work progress  Summary and prospects S. Borjabad 7th JRA-1 Zaragoza Nov´07

3. Copper Electroforming Process Electroforming is a method of producing pieces by the deposition of a metal onto a mold (mandrel) which is subsequently removed High-purity copper parts Accurate surface reproduction Underground process Chemical & electrolitic improvements S. Borjabad 7th JRA-1 Zaragoza Nov´07

4. Process Parameters & Key Elements ConstituentConcentration CuSO 4. 5H 2 O188 g/l H 2 SO 4 75 g/l HCl30 mg/l Thiourea3 mg/l Mandrel turns during the whole process producing a homogeneous deposition Electrolyte circulates with continuous filtration to eliminate impurities Covered bath avoids air and dust contamination Plating is done over polished and cleaned stainless steel mandrels with the same shape of the relevant copper parts H 2 SO 4 improves the electric conductivity HCl and Thiourea affect copper crystal nucleation and grain size Constituents of the Electrolyte (Brodzinski et al.,A292 (1990) 337) Copper Electroforming Process S. Borjabad 7th JRA-1 Zaragoza Nov´07

5. Filter and Pump Electrolitic Bath Voltage Supply Electronic Control System Temperature and pH sensors Electroforming Set-Up Copper Electroforming Process Electrolyte circulation Inert cover gas (N 2 ) Rotation Speed & Direction Plating modes Temperature & pH sensors Parameters DAQ system S. Borjabad 7th JRA-1 Zaragoza Nov´07

6. Review of objectives and work progress  Electroforming process parameter tuning  Electroformed copper parts with complex geometry  Monitorization of parameters during the electroforming process  Radiopurity measurements of electroformed copper parts  Chemical & electrolytic improvements  Electroforming in steps to fabricate cryostat copper components S. Borjabad 7th JRA-1 Zaragoza Nov´07

7. Electroforming Process Parameter Tuning Optimum parameters: 3 A/dm 2, 2 rev/s, forward-reverse rotation Parameters: Current Density, Speed Rotation and Direction Rotation Review of objectives and work progress Goals Smooth surface Homogeneous copper distribution Without periodic machining process S. Borjabad 7th JRA-1 Zaragoza Nov´07

8. Electroformed copper part for PMT encapsulation (collaboration ANAIS) Hexagonal & cylindrical electroformed copper parts Isolated areas with Teflon, parafine or silicone Smooth surface Accurate surface reproduction (corners) 1.5 mm of thickness Electroformed copper parts with complex geometry Review of objectives and work progress Complex mandrel Smooth surface Homogeneous distribution Final machining process S. Borjabad 7th JRA-1 Zaragoza Nov´07 Auxiliary anode Isolated areas with Teflon 1.5-2 mm of thickness Soldering tests with electroforming in progress

9. Review of objectives and work progress Electroforming process parameter tuning Electroformed copper parts with complex geometry  Monitorization of parameters during the electroforming process  Radiopurity measurements of electroformed copper parts  Chemical & electrolytic improvements  Electroforming in steps to fabricate cryostat copper components S. Borjabad 7th JRA-1 Zaragoza Nov´07

10. Parameters monitorization during the electroforming Review of objectives and work progress S. Borjabad 7th JRA-1 Zaragoza Nov´07 Temperature & pH sensors DAQ software Parameters measurement system Electroforming Parameters Current (I) Voltage between electrodes (ΔV) Electrolyte Temperature & pH Evolution during the process Electrolyte properties

11. Review of objectives and work progress Electroforming process parameter tuning Electroformed copper parts with complex geometry Monitorization of parameters during the electroforming process  Radiopurity measurements of electroformed copper parts  Chemical & electrolytic improvements  Electroforming in steps to fabricate cryostat copper components S. Borjabad 7th JRA-1 Zaragoza Nov´07

12. RadionuclideUnits (mBq/kg) Th series 212 Pb≤ 16 228 Ac≤ 25 U series 234 Th≤ 32 234 Pa≤ 90 226 Ra≤ 24 214 Pb≤ 3 214 Bi≤ 6 235 U≤ 1.4 137 Cs≤ 7 40 K≤ 90 60 Co≤ 7 56 Co≤ 3 57 Co≤ 8 58 Co≤ 5 Preliminary radiopurity measurement of electroformed copper The levels of radiopurity in an electroformed copper part were previously measured with a HPGe detector (1Kg Ge) at the Canfranc Underground Laboratory (LSC). Copper mass: 161 g Measuring time: 5 d Copper part into a Marinelli container Copper around the HPGe detector A standard- electroformed copper part (commercial chemicals & at sea level) (Data Analysis courtesy J. Puimedon) Review of objectives and work progress S. Borjabad 7th JRA-1 Zaragoza Nov´07 New measurement in progress

13. Review of objectives and work progress Electroforming process parameter tuning Electroformed copper parts with complex geometry Monitorization of parameters during the electroforming process Radiopurity measurements of electroformed copper parts  Chemical & electrolytic improvements  Electroforming in steps to fabricate cryostat copper components S. Borjabad 7th JRA-1 Zaragoza Nov´07 In progress Next steps

14. Summary and Prospects  Electroformed copper parts with smooth surface and without machining can be manufactured by means of the tuning of process parameters.  Copper parts with different geometry (hexagonal, cylindrical) can be achieved by easy modifications.  Radiopurity measurements of electroformed copper parts are in progress.  Soldering tests to join copper parts with electroformed copper are in progress. SUMMARY PROSPECTS  Chemical & electrolitic improvements: CuSO 4 purified by recrystallization, high- purity acids and anodes, CoSO 4 and BaSO 4 to reduce Co and Ra isotopes.  Electroforming in steps to fabricate different copper parts such as cryostat components.  This facility will be installed at the new (enlarged) Canfranc Underground Laboratory as soon as the clean room is ready. S. Borjabad 7th JRA-1 Zaragoza Nov´07