https://pfspipe.ipmu.jp/jira This file is an XML representation of an issue en-us 8.3.4 803005 13-09-2019 https://pfspipe.ipmu.jp/jira/browse/INSTRM-1671 Instrument control development <p>In the June 2021 run, the Cobra arm lengths were measured (<a href="https://pfspipe.ipmu.jp/jira/browse/INSTRM-1532" title="Updating the L1/L2 arm lengths when PFI is on telescope" class="issue-link" data-issue-key="INSTRM-1532"><del>INSTRM-1532</del></a>). The result showed that the arm lengths were different from those measured in September 2021. Since the measurement on the test stand (e.g. Feb and Mar 2022, see the report in INSTRM-2532 for the details) were the same as each other, the reason for the difference on the telescope needs to be studied.</p> <p>At the ICS/PFI+MCS telecon on 8 July, the following action were suggested:</p> <ul> <li>Check the variation of the arm lengths themselves across the cobras, rather than the difference between the two measurement</li> <li>Re-anlyse the 2021-Sep data with the latest software and compare the results</li> </ul> INSTRM-1671

Study why the Cobra arm length were different between Sep 2021 and June 2022.

Task Normal Done Done chyan yuki.moritani EngRun Fri, 15 Jul 2022 07:34:29 +0000 Thu, 13 Oct 2022 13:03:22 +0000 Sat, 1 Oct 2022 22:28:06 +0000 0 3 <p>This requires taking more data during the Nov 2022 run when the PFI is on POpt2, on order to compare the arm length data that was taken during the June 2022 run.</p> <p>Attached is the L1/L2 arm lengths measurements of two different epochs. As we can see from the plots, the arm lengths are very consistent in two different measurements. Although the arm-length differences between bench and telescope are still unknown, yet we are confident that the system is stable on telescope. It is know the the measurement from bench comes from a very fast optical lens. It is suspected that the difference may caused by the different transformation function. At this point, I suggest we close this ticket and open another ticket if we are still interesting on the art length differences between bench and telescope.</p> <p>Closing ticket following Chi-Hung recent comment.</p> Development Rank 0|02qpi3: Sprint preEngRun08Nov Story Points 2.0