PROTO Working Group Meeting

Europe/Rome
Nicola Canci (Istituto Nazionale di Fisica Nucleare)

Partecipants:

Giuseppe Matteucci, Nicola Canci, Alessio Caminata, Bianca Bottino, Daniel Huff, Grigory Dolganov, Marco la Commara, Gabriel Botogoske, Mauro Caravati, Roberta Calabrese, Sosuke Horikawa, Francesco Di Capua, Peter Skensved, Dmitrii Rudik, Gianfranesco Grauso, Marisa Gulino, Giuliana Fiorillo, Luciano Pandola, Marco Rescigno, Yury Suvorov

17:03 Start of the meeting - Quick updates

NCC: We received the Cryostat flange after a mechanical modification. We need to clean the flange and remove the old indium from the cryostat (Roberta Calabrese is taking care of this last point). We also received a new plastic rod that is going to house PT100 sensors. 
GM: Next week I would like to have a discussion on the tests and measurements foreseen for the upcoming Proto-0 campaign. I will share the run program with everyone for comments and suggestions - then I would like to ask Grigory to produce fields simulations for the desired fields to know which potential values to use.

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17:15 Daniel Huff, Giuseppe Matteucci - Grid Wire Substitution and Tension
DH: Following a discussion with Nicola and Giuseppe, we have discovered that the wire grid has a slightly different size than the one in Napoli.
I will produce wires of different lengths (four different lengths, 8 wires in total) based on the measurement provided by Napoli and try to ship them tomorrow or Wednesday.

GF: How does a change in length translate to a different tension?
GM: I've estimated this quantity. We expect about 30 N of force for each 1 mm of stretch (~250GPa Young modulus)

GM: I've measured the tension of about 10 our wires. The average is 7.5 N with variability of +/- 3 N. That's a lot compared to 3 +/- 0.25 N reported by DH for the mockup. I propose Daniel provides more spare wires and I will substitute the outliers after measuring the tension of all wires.
DH: Ok, I will do. What is the target tension?
GM: 6 N. Please, produce about 10 spare wires, and if you need an extra more days that's totally fine.
DH: Ok

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17:25 Luciano - Update on Gas Pocket Meter
Quick update on Gas Pocket Meter mechanics. The big teflon piece is currently being machined and should be ready at the end of the week, while all small parts are done.

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17:30 Gianfrancesco - Cryogenics Update
We started working on connecting Lakeshore to Slow Control.
Heater block is being recabled at Electronic Lab (SER).
Next week I will have a short presentation about this.

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17:34 Grigory - Update on the Fields Simulation
Small update on my previous presentation. I simulated electric field with 0, 1, 2, 3 wire missing at the edge of the grid frame. It’s much better than with the wire that is currently missing. 
Finally, a field dis-uniformity is noticeable close to the reflector. It’s a local effect and does not influence the working of the TPC.
Finally, I tested positive anode potential of 0, 2kV and 5.1kV. This reduces the field strength outside of the TPC (so it’s better), but it’s risky as with higher potential we have a higher probability of corona discharge ignition.

GM: How is the extraction field affected from a lateral wire removed? At the current position (23th), you reported a 9% decrease in extraction.
GD: I've not measured it, but it's probably less than 1%. I estimate 0.1% variation.

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17.50 Wrap Up
NCC: Any more comments?
Mauro: Question: how will you ensure planarity of the TPC? This seems important for gas pocket related studies.
NCC: We don't have a way to ensure planarity of the anode or the TPC when the cryostat is closed. We will do our best while assembling the TPC and mounting it on its support structure.

 

There are minutes attached to this event. Show them.
    • 5:00 PM 5:10 PM
      Proto-0 Activity Updates 10m
      Speaker: Nicola Canci (Istituto Nazionale di Fisica Nucleare)
    • 5:10 PM 5:20 PM
      Proto-0 grid and wires 10m
      Speakers: Daniel Huff (University of Houston), Giuseppe Matteucci (Istituto Nazionale di Fisica Nucleare)
    • 5:20 PM 5:30 PM
      Gas pocket housing 10m
      Speakers: Luciano Pandola (Istituto Nazionale di Fisica Nucleare), Marisa Gulino (Istituto Nazionale di Fisica Nucleare)
    • 5:30 PM 5:40 PM
      Updates on cryogenic system and slow control 10m
      Speakers: Gianfrancesco Grauso (INFN Napoli), Riccardo De Asmundis (Istituto Nazionale di Fisica Nucleare), Yury Suvorov (Istituto Nazionale di Fisica Nucleare)
    • 5:40 PM 5:50 PM
      Proto-0 Fields 10m
      Speakers: Grigory Dolganov, Mauro Caravati (GSSI - Gran Sasso Science Institute)
    • 5:50 PM 6:00 PM
      AOB 10m
      Speaker: Nicola Canci (Istituto Nazionale di Fisica Nucleare)