Testing Goals and Notes

Sarah Lockwitz, FNAL

Mini-Review Planned for July 28, 2016• Tentative Charge:

• 1. Is the proposed setup and test plan sufficient for evaluating the proposed ProtoDUNE-SP field cage design with regard to high voltage? 

• 2. Are there any electrical or mechanical problems with the design of the test apparatus?

• 3. Are there any safety issues to be addressed?

• 4. Does the TSW contain the needed resources to do this?

• Tentative Schedule:

• 1. Overview and Motivation for the Test (20 min+10)

• 2. Plan for ProtoDUNE-SP HV (20+10 min) (Bo or Francesco)

• 3. Technical Review:  Mechanical Specifications (Jeff) (25+15 min)

• 4. Technical Review:  Electrical Specifications (Glenn) (25+15 min)

• 5. Cryogenics and plan for instrumentation (Alan with input from WM on camera) 

• 6. Phase II Plans (Cheng-Ju) (20 min)

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Goals of Testing: Ensure that the ProtoDUNE design is a success

• Expose any weaknesses so that we can fix them

• Test the high voltage features of the ProtoDUNE design

• The beam plug is a challenging feature of the design

• Beam plug must be tested in the field cage

• There are enough untested features of the field cage that testing everything at once would make it difficult to determine the source of instabilities (if they arise)

• Test the field cage without the beam plug first. Characterize performance.

• Test the field cage with the beam plug to understand the beam plug performance.

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Testing Goals & Plans• We cannot do a full size test of ProtoDUNE

• We will do a partial & scaled test in 35t. (Size effects?) • Cathode at full voltage (-180 kV), 10 TPC stages at correct voltage, anode plane at -47 kV, resistor chain to ground.

• TPC has 4 parallel chains of 5.5 GΩ (11 stages x 500 MΩ. The 500 MΩ is from 2 1 GΩ resistors in parallel between each profile)

• Resistors will have surge protection. The last stage beyond the TPC is under development. • Test interfaces.

4180171162153147 171 162 153 147

• Really want to evaluate these edges. • First one is at 177 kV • To get that voltage w/o the tail of resistors, one

really gets into large tube to tube ΔVs (~20 kV)

What is a successful test?

• We want the HV+TPC design to not adversely affect data-taking at ProtoDUNE

• TPC should be robust (no breakage of field cage from HV)

• We shouldn’t have instabilities that affect data-taking

• HV system should not create troublesome noise for the DAQ (filter can be tested separately)*

• System should not create light that adversely affects data-taking

• Have not found this to be an issue in a non-broken TPC

• Might want to put a PMT in the cryostat

• Should not have freq. breakdowns (relative term, aim for zero).

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Let’s think about this…it

would be good to have an

answer by the review

Rough Schedule• July:

• Complete design of field cage components including TPC circuit (resistors & varistors)

• Order long lead time materials

• Mini-Review week of July 25th

• Fabricate parts

• August:

• Remove 35t TPC

• Continue fabrication

• Test fit?

• Clean pieces

• September: Install PhaseI HV Test

• October: Purge, cool down & fill cryostat

• November: Perform Test

• December: Transfer LAr to LAPD. Warm up cryostat. Takes a little over 1 month

• January: Install Phase II

• February: Purge cooldown & fill

• March: Test Phase II

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Monitoring Ideas• Toroid: Polarity of first pulse tells you where the

voltage drop was

• Pick off/Field cage termination (required port)

• HV Supply: Heinzinger offers much better current readout ability (~100 nA vs 10s uA with a Glassman)

• Camera: M. Kordosky & group (required window(s) and/or feedthrough ports)

• PMT/SiPMs? (required ports)

• Any other ports needed?

• Not planned at the moment: Antenna, microphones

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Blips: Toroid and FCT signals while running • Do not cause trips • Can affect data-taking (shield plane reduces this) • 35t and another experiment have seen them

• Both positive & negative polarities • Small test stand has not. Not a deal breaker at this time, but something to be aware of.

Membrane Performance?

• The proposed test does not evaluate the effect of the TPC+cryostat membrane performance. This should be a low risk (40 cm away).

• The 35t was done by a Japanese company and has a different profile than what Proto-DUNE will have (GTT).

• We have some GTT profile onsite. We have some that people are willing to allow us to test.

• If there’s a strong motivation, we can test them in a small test vessel we have onsite with access to TPC-quality argon. Would only be able to test up to ~100 kV at the moment (likely < 1 inch). We would have to pay for the argon.

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A Note on Cable Terminations

• I saw Bo has requested DS 2134 cable.

• I am sure people already have ideas about cable terminations.

• If anyone would like an additional idea, we’ve used this technique for cable terminations at FNAL. Tevatron used them for decades.

• I’m willing to share parts, help with drawings, etc. if anyone wants to use this.

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Cleaning G10/FR4

• An option for cleaning the G10/FR4 parts is an ultrasonic bath the TD at FNAL has

• The parts in the photo are ~2.5 m in length

• On the G10, the cleaner used was Elba-Clean 65 (total cost to arrive at the lab was ~$1k)

• If there’s interest, I can ask if this is available to use at the end of the summer.

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From T. Strauss