Testing Goals and Notes Sarah Lockwitz, FNAL Mini-Review Planned for - - PowerPoint PPT Presentation

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)

2

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.

3

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.

4

180 171 162 153 147 171 162 153 147

• 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).

5

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

6

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

7

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.

8

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.

9

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.

10

From T. Strauss