Mounting TPCs in SVX Dock During Phase II Tomorrow I will meet with a company engineer to update the BEAST TPC vessel design. I've attached some slides (p2-12) that I plan to discuss with him. I would like to suggest the following for phase 2, and welcome feedback from the BEAST group –we mount TPC and He-3 tubes separately, I think this will make it easier for us to freeze the designs in a timely manner –University of Victoria designs the He-3 tube mounts –we use the free SVD dock positions for the TPCs, and the free VXD positions for the He-3 tubes –we mount the TPCs with small brackets, similarly to the dock boxes. This way we don't need to remake our TPC vessels in case there is a change in the CDC cover design or mounting holes, or even just in case there is a communication problem between the groups in involved. See p 7 for conceptual design. –the TPCs will have all services except one HV cable coming out at the end facing the CDC. The HV cable comes out the side. This way we keep to outer/inner r regions free, as Tscharlie preferred for allowing cable/tube routing across detectors in phase 3. –for TPCs we are planning to stay below 41 cm total in z (see page 14). That includes everything, bracket, vessel, cables Main question to Alex and Tscharlie: is 41cm OK for both forward and backward? How much extra space is there? 1 Sven Jan 13 th BEAST Meeting

Planned Changes to TPC 1.remove KF feed-throughs & claw clamps from side A and B, replace with custom feedthrough plate on side A 2.add sixteen bolt holes for vessel mounting 3.modify lids for slight overpressure, in addition to vacuum, operation  Thicker lid and/or additional lid bolts 4.minor dimensional changes (length) – reduce length – move EDM slot positions. Could now be milled for cost savings, OK if they don’t extend to bottom of vessel. 5.all vessel and thread dimensions metric 6.titanium inserts for all threads 7.[tbd] add one KF-16 feedthrough for HV on long end Open questions 1.8kV feedthrough position and mounting

Current design Documentation at 3 Side A Side B 31 cm outsize length in z

Current feed-throughs on endplates 13.0 cm 10.4 cm 2.16” HV:< 5kV 4 pins) LV: <=5 V (<=50 pins) KF40 to vacuum pump Pressure relief gas in gas out UHV: 20 kV (1 pin) KF-40 KF ” Side B Side A

REQUESTED CHANGES 5

1. remove KF feed-throughs & claw clamps from side A and B, replace with custom feedthrough plate on side A We need to fit this vessel in a tight space, and need to reduce length. The current clamps are also a bit fiddly. We will replace the fittings with a single, custom feedthrough plate, similar to the one shown below. This plate should become a small lid, attached with bolts, sealed with o-ring. Questions: Can HuntVac machine the lid, and we get feedthrough vendor to weld in feedthroughs? Alternatively, could HuntVac also do this welding? December 2, 2014Rosen/Vahsen TPC corner concept6 Side A

2. Additional bolt holes for vessel mounting Top view/no scale Internal corners require fillets Mounting bracket to CDC end ring M6 w/ Ti insert 4 (?) mm Clearance Mounting holes: M4 blind, TI insert Vessels will be mounted on an “end plate”, similar to photo below, right. Vessels will be mounted with side A facing the end plate To avoid interference between mounting and the new feedthrough plate/lid, we’d like to add four mounting holes (as shown in sketch below), near each corner of vessel, i.e. eight holes total near side A + another eight near side B. (sketch shows two holes, but there should be another two below) Corbin, what bolt sizes do you recommend (M4/M6 are guesstimates) end plate vacuum vessel custom feed-through lid

December 2, 2014Rosen/Vahsen TPC corner concept8

December 2, 2014Rosen/Vahsen TPC corner concept9

3. Improved lids, suitable for slight overpressure, in addition to vacuum  Thicker lid and/or additional lid bolts We want to operate without leaks in any of the following three scenarios a)vacuum in vessel (i.e. -15 psig) b)same pressure inside and outside (0 psig) c)slight overpressure in vessel (~ +5 psig) We have severe space constraints. Two options –Thicker lid in middle only (cannot extend corners due to lack of space) –Thicker vessel wall to accommodate two extra bolts in lid? December 2, 2014Rosen/Vahsen TPC corner concept10

4. minor dimensional changes (length) –reduce length by ~5cm, for 26 cm outside length –move EDM slot positions. Both to start 5cm from inner wall. Slots can now be milled for cost savings, OK if they don’t extend to bottom of vessel. 11 ~31 cm  26 cm 5cm

Other Requests & Open Questions all vessel and thread dimensions metric titanium inserts for all threads Open questions 1.Vessel length could change one more time 2.8kV feedthrough position and mounting add KF-16 feedthrough to long side of vessel? Or permanently weld in the feedthrough? December 2, 2014Rosen/Vahsen TPC corner concept12

BACKUP SLIDES 13

Z-length of TPC Need Total length <= 41 cm December 2, 2014Rosen/Vahsen TPC corner concept14 vessel lidlid Plug Cable bend radius bracket <=15cm <=26cm outside vessel, z cm of z-space inside vessel 5cm 8kV feedthrough (KF16)

December 2, 2014Rosen/Vahsen TPC corner concept15

December 2, 2014Rosen/Vahsen TPC corner concept16