LVDT card recovery document and related topics.

[MiyoKouseki]

Dear all,

I recently uploaded a document about the LVDT card recovery procedure at [JGW-T2012128.](https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=12128)

In TypeB/Bp I would like Washimi-san and me to be in charge of the corresponding measurements. Washimi-san, would you mind reading the document, please? As always, please give me feedback in case there is any. Thank you in advance.

It is not my decision, but I would tend to suggest Type-A team to get acquainted with the topic. None of Type-A LVDT cards have been surveyed and it's a lot of work. These measurements always require two people.

There are several closely related topics which we need to talk about in a meeting:

1. I have questions for Nikhef that are written in the document. I will forward it to them.
2. The procedure described has worked in SR3 before, but we should make an experiment in which the LVDT calibration process is repeated after the replacement. Can this be done by someone in Mitaka? It seems all the necessary equipment is already there.
3. Tanaka-san will take some of our card for hardware modification.
  * We need to survey those LVDT cards before he takes them away. When will we do this?
  * As far as I understand, given the old calibration factor, he has to give us a procedure to calculate a new calibration factor.
4. We need to allocate time to survey all of our LVDT cards. When are we going to do this?
5. The cards are difficult to use, they require improvement. It would be nice if we could ask Nikhef and AEL to make things somewhat differently to make our work more efficient.
6. After checking SRM LVDT driver on the 14th of August, I'm concerned about temperature changes affecting the resistance values of potentiometers (thermal cycle in the screw). The report is not in the klog yet, sorry about this.
Thank you very much in advance and I apologize for the length of the message.

Regards,

Fabian

ToDo list to close the issue

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• [ ] Done. Move to "Review/QA"

[naibafomsare]

I got feedback about the LVDT card recovery procedure from Nikhef.

• Alessandro Bertolini says the procedure outlined in the document is correct and gives additional comments which I will incorporate in the document.

• A highlight of his comments is that they plan to review the card design for ET Pathfinder and that will be our chance to give them feedback. It would be greatly beneficial for both parties to let them know about Tanaka-san's work with the cards, so we could eventually use an improved version out of the box.