Difference between revisions of "Heavy Gas Cherenkov"

Latest revision as of 16:24, 18 February 2025

info

email list

HGC emaillist,"solid_hgc at jlab.org", registration and archive

Integration into SoLID

refer to SoLID_Engineering_Integration_and_CAD page Engineering Integration and CAD

prototyping and R&D

window and pressure vessel

• window materials
  • tedlar/mylar/tedlar from Madico
  • "We have used this type of material for spectrometer vacuum windows. It is made of high end sail cloth (actual sail material for boats). It is not the easiest material to work with but will most likely work for you. You may have to pretension the cloth depending on the manufacturer." from David Meekins of jlab target group, https://www.sailmakerssupply.com/product/racing-laminate-sailcloth-seconds/sailcloth, It's actually Kevlar/Mylar laminates
  • cheap kevlar, http://www.mcmaster.com/#kevlar/=14kwgqs , Its thickness 0.6mm is a bit bigger than 0.4mm used by BNL vacuum window, Not sure if it's because it's "cut resistant"
  • 2024 Al ~1mm thick

• Regina window tests
  • test 0: Test of 1.5mil Tedlar/3 mil PET/1.5 mil Tedlar material obtained from CLAS LTCC. with video showing slow motion of bursting and fast motion of the test
  • test 1: Full size test of 5 mil Mylar/12 mil Kevlar window material. Dec 5, 2016.
  • test 2: Full size test of 5 mil Mylar/12 mil Kevlar window with circumferential epoxy. Feb 16, 2017.
  • test 3: Small size test of double layer 5 mil Mylar/12 mil Kevlar window with epoxy coating. June 9, 2017.
  • test 4: Small size tests of five different configurations of 5 mil Mylar/12 mil Kevlar window with epoxy coating. Aug 16, 2017.
  • test 5: Tests of small Carbon windows in 2019.
  • test 6: Initial tests of full-size Carbon windows in 2019.
  • test 7: Final tests of Carbon and Aluminum windows in 2021.

• Regina prototype vessel leak tests
  • Sealing and leak tests of prototype vessel in 2021.

readout

gas

survey in 2023 https://indico.bnl.gov/event/19346/contributions/76904/attachments/47745/80967/%5B20230531%5D%5BdRICH%5D%20Photosensors.pdf

mirror

• SoLID HGC mirror drawing and SBU half mirror Al support structure at p12 of https://solid.jlab.org/DocDB/0002/000254/003/solid_hgc_zwzhao_20200608.pdf

• RICH mirror requirement survey 2023/06 https://solid.jlab.org/files/cherenkov/mirror/RichMirrors.pdf

• Zhiwen Zhao's mirror test info https://solid.jlab.org/files/cherenkov/mirror/mirror_test_zwzhao.pptx

• Duke and SBU activity on 2/5/2025 https://indico.bnl.gov/event/26329/

• reflectivity test stand RD effort to reach to 200nm for large mirror
  • Bill Li's experience about air absorption to UV light. roughly, normal air 250nm, dry air 210nm, N2 180nm
  • Tyler's slide 2023/06/12 [1]
  • Tyler's note 2023/08/29 [2]
  • Tyler's note 2023/09/14 [3]
  • Tyler's slide 2023/10/10 [4] and minutes [5]
  • Tyler's 2023/11/06 minutes [6]

• test stand info
  • BNL monochromator based test stand, can only measure reflectivity on small mirror sample at least down to 200nm
  • HallC SHMS HGC mirror monochromator based test stand info, ch5 of https://misportal.jlab.org/ul/publications/downloadFile.cfm?pub_id=12091, some of its parts are in ESB and need work to use again
  • spectro-photometer (according to Marco Contalbrigo who has a broken one at INFN Ferrara) for example https://resources.perkinelmer.com/lab-solutions/resources/docs/bro_lambda950850650americas.pdf . This can be used to measure the reflectivity of the mirror surface as a function of the wavelength, if used in conjunction with its integrating sphere. As is is not easy to work with large or spherical mirrors, usually small samples are used (same substrate, same coating cycle). I expect spectrophotometer should provide better precision and therefore a calibration/validation benchmark. What is the declared precision of the Tyler system (I mean error on absolute reflectivity) ? Is it nominal or measured?
  • CLAS12 RICH mirror test stand info
    • https://clasweb.jlab.org/wiki/images/3/35/CMA_report.pdf, That refers to a mirror technology that was rejected (rohacell core, not stable enough) but explain part of the characterization we made.
    • additional information from the initial evaluation of the real mirrors: https://clasweb.jlab.org/wiki/images/4/4c/2016-05-20_SphericalMirrors.pdf, https://clasweb.jlab.org/wiki/images/2/2a/2016-07-01_SphericalMirrorsCMM.pdf, https://userweb.jlab.org/~tlemon/RICH/D0_Measurement_Results_2016-10-21.pdf
    • d0 and Shack-Hartmann at jlab detector support group (example as https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=5287)
    • reflectivity at jlab detector support group. the new fiber optics reflectivity test-station: https://userweb.jlab.org/~tlemon/RICH/New%20Reflectivity%20Test%20Station%202022-04-22.pdf
      • old reflectivity test station is monochromator based and similar to the hallc setup, but his new fiber optics based setup is much more compact and easy to use.
      • new fiber optics reflectivity test station was optimized down to 350nm so far
      • more details at https://solid.jlab.org/files/cherenkov/mirror/RICH-mirror-tests-info/
    • mirror geometry measured at jlab survey group
      • For the mirror surface mapping done by survey group, an example of the data gotten from that is on page 7 of the slides linked below. https://www.jlab.org/div_dept/physics_division/dsg/presentations2/RICH%20Status%20Report%20Aug%2010%202016.pdf. The data were gotten with survey group's portable CMM (coordinate measuring machine). They then gave detector support group the data to do some analyses, like calculating the mirror dimensions and radius of curvature with the data points. Example results from these analyses start on page 7 of the slides linked below. https://www.jlab.org/div_dept/physics_division/dsg/presentations2/RICH%20Status%20Update%202016-09-28.pdf
      • https://www.jlab.org/accel/survalign/scopeservices/inspection.html (according to Marco Contalbrigo) the first machine (in that web page) could serve in measuring the mirror dimensions (thickness, diagonals,...). This is important to verify the mirrors do not interfere each other (a minimum clearance is required for alignment, but one wants to minimize the dead area). The JLab survey group actually measured the mirror dimensions with a portable version of the first coordinate measuring machine. The second instrument (in that web page) was used to verify the mirror position inside the RICH after assembling. It was also done by JLab survey group.