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LS3 dust measurements

→ Europe/Zurich
    • 10:30 → 11:30
      Meeting - LS3 dust measurements 1h
      Speakers: Christoph Wiesner (CERN), Guillaume Jonathan Rosaz (CERN), Ingrid Midtbust Hjelle (EPFL - Ecole Polytechnique Federale Lausanne (CH)), Mr Philipp Alois Ziegler (Goethe University Frankfurt (DE))

      BST:

      • During LS3 140 connections will be cut, giving access to 240 beamlines.
      • It will be taken optical measurements in these beamlines. The device will have a camera (endoscope) with a small backlight.
      • The longitudinal location of the device inside the beam screen will be approximately known
      • Guillaume will send the specifications of the camera.
      • BST will start on the 11th of November in Sector 81 and last until the end of 2028.

      Camera testing in lab:

      • We could create a setup in the lab with a beam screen in which we place dust, then we can send the camera into it and have a baseline for what we expect to see of dust grains.
      • It will be difficult to derive the size of the dust grains from the camera recording.
      • There exist a video from a previous measurement of the Q5L8 where dust was clearly visible. Guillaume will provide the link to the video.

       

      Mock-up of beam connection:

      • MSC has several mock-ups of the interconnects that they use for teaching the cutting procedure.
      • We could place a silicon wafer close by when they perform test cutting and then measure the dust/metallic debris on it after. (Estimate dust creation from cutting in contrast to dust contamination from existing dust in the tunnel.) Dust could then be analysed by MME.

       

      Dust release/creation due to shifting/sliding:

      • Guillaume pointed out that shifting and/or sliding of RF fingers after installment can potentially create new dust grains.
      • We could design experiments where we purposely shift the beam screen and measure if this creates dust.

       

      Dust measurements during LS3:

      • 4 magnets will be exchanged during LS3. In principal, wipe test samples could be taken and analysed. To be checked with MSC (Sandrine/ Jose Ferradas Trotino).
        • Cleaning installation procedure for beam screens could be discussed with Cedric Garion (VSC).
      • It will be difficult to perform wipe test in the tunnel inside the beam screens before BST (small opening, only the very beginning is easily reachable and risk to move dust further downstream).
      • A simple particle counter could be installed in the tunnel before/during the BST to evaluate the dust background at the time of installation (to be possibly correlated to UFO rates after LS4).

       

      Actions:

      • Provide list of to-be-treated half cells: Guillaume
        • Compare with UFO rates and identify spots with especially high/low UFO rate to prioritise dust measurements/observation: Ingrid (with input from Anton)
      • Provide specifications for camera used for BST: Guillaume
        • Compare to camera used at CU Boulder: Philipp Z.
      • Provide link to video with visible dust from Q5L8 campaign: Guillaume
      • Evaluate option for wipe test inside the beam screen for exchanged magnets: Ingrid, Christoph, Rudiger
      • Evaluate option for dust measurement during test cutting at mock-up: Ingrid, Christoph with MSC input (contact: Herve Prin)
      • Evaluate option for dedicated experiment for dust creation due to RF finger sliding: Ingrid, Christoph with VSC input
      • Evaluate feasibility (specifications, recording options, costs) for simple stand-alone particle counter to be installed in the tunnel during BST: Ingrid
      • Provide link/info about electric "dust cleaner" as developed by LASP, Boulder: Philipp Z.