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| − | '''Draft Outline for Commissioning'''
| + | [https://halldweb.jlab.org/hdops/wiki/index.php/Fall_2014_Commissioning_Plan Hall D Official Fall 2014 Commissioning Plan] |
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| − | =Review Sequence=
| + | [[Preparations for Internal Photon Beam Commissioning]] |
| − | # Electron beam
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| − | #* OSP and small internal review in order to power and map tagger magnet
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| − | #* Transfer of tagger magnet operation to accelerator, so that it can be reviewed as part of ARR II (nominally Jan)
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| − | # Photon beam
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| − | #* Review of photon beamline (radiator to photon beam dump). Nominally scheduled for March, at least 3 months prior to beam delivery
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| − | #* This includes review of the tagger hodoscope and microscope, profile monitor, active collimator, halo monitors, and other photon beam monitors.
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| − | # Experimental Equipment Hall D
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| − | #* Experimental apparatus in Hall D (prior to use with beam)
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| − | =References=
| + | [[Draft Outline for Commissioning]] |
| − | <ref name=TN07022> Freyberger, A. and Tiefenback, M., "Diagnostic Specifications for the 12 Gev Upgrade," 2007, JLAB-TN-07-022 </ref>
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| − | <references />
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| − | =Electron beam=
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| − | ==Goals==
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| − | # Safely deliver electron beam to the electron beam dump \cite{shielding}
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| − | ==Assumptions==
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| − | # Accelerator has qualified the machine protection system (MPS) and the personnel safety system (PSS) for the tagger building
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| − | # Assume steel blocks (> 20" thick) are stacked in front of the photon beam pipe to the hall to prevent any direct beam spray from traveling down to Hall D.
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| − | ==Checklist at low current I~1uA, [[tune mode]] ==
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| − | # Check beam is centered on the beam dump
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| − | # Scan position of beam over the area of the radiator
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| − | # Check single rates at various positions in the tagger enclosure (electronic racks)
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| − | # Check single rates at the location of the tagger microscope
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| − | # Check single rates at the location of the tagger broad band hodoscope
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| − | # Verify tagger magnet excitation curve matches predictions, e.g. for different beam energies
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| − | # Verify controls for all beamline elements work as expected
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| − | # Check radiation levels in the tagger hall <ref name=TN08033 />
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| − | # Establish location in the hall for electronic racks safe from radiation
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| − | # Identify sources of background (scraping) in the hall.
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| − | # Check Fast Shutdown system
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| − | ==Checklist at low current I< 100 nA?, CW==
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| − | # Verify proper operation of beam as in pulsed mode
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| − | # Check single rates at various positions in the tagger enclosure (electronic racks)
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| − | # Check single rates at the location of the tagger microscope
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| − | # Check single rates at the location of the tagger broad band hodoscope
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| − | # Identify sources of background (scraping) in the hall.
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| − | # Check out amorphous ladder controls
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| − | # Commission halo pmts located on the electron beam pipe to the dump (i.e. adjust HV settings)
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| − | # Change radiators and check relative thicknesses using halo pmts
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| − | # Use accelerator harp to determine beam centroid and width
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| − | # Use amorphous ladder harp to verify beam centroid, width and halo
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| − | ==Checklist at high current I>?, CW==
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| − | # Verify proper operation of beam as in low current situation
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| − | # Check single rates at various positions in the tagger enclosure (electronic racks)
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| − | # Check single rates at the location of the tagger microscope
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| − | # Check single rates at the location of the tagger broad band hodoscope
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| − | # Check radiation levels in the tagger hall
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| − | # Check radiation levels in Hall D
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| − | # Check radiation levels in the tagger service building
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| − | ==Abnormal conditions==
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| − | # High radiation levels in any or all areas of interest
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| − | # Accidental loss of power to vertical bend string
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| − | # Accidental loss of power of tagger magnet
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| − | # Accidental loss of vacuum
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| − | =Photon beam=
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| − | ==Goals==
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| − | # Determine characteristics of photon beam in Hall D
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| − | # Safely deliver photon beam through the hall to the photon beam dump
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| − | | + | |
| − | ==Assumptions==
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| − | # Accelerator has qualified the machine protection system (MPS) and the personnel safety system (PSS) for Hall D and the counting house
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| − | # Delivery of electron beam through tagger to electron dump has been accomplished
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| − | # Operation is assumed CW, but perhaps one should start with pulsed mode
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| − | # Amorphous radiator installed with $10^{-5}$ thickness, typical
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| − | # Steel blocking photon beam pipe in tagger hall have been removed
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| − | # Initially the solenoidal magnet is off
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| − | ==Notes==
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| − | # We should identify all apertures along the beam line to be aware of possible locations for scraping
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| − | ==Checklist, current I< 100 nA==
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| − | ==Location: before active collimator==
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| − | # Require profile monitor to be installed and operational
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| − | # Require active collimator to be installed and operational
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| − | # Require halo monitors 1 to be installed and operational upstream of cave wall
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| − | # Check that detector elements in Hall D are off and prepared
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| − | # Check profile of photon beam exiting the beam pipe into cave
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| − | # Determine center of photon beam relative to photon beamline
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| − | # Compare with response of active collimator
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| − | # Use this exercise to calibrate active collimator response
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| − | # Scan the electron beam over the face of the radiator to establish aperture and check that photon beam profile behaves as expected
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| − | # Check feedback signals of active collimator to control system. (Once understood, these can be used in real time to correct the beam position on the collimator).
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| − | # Study the stability of the beam with and without feedback from the active collimator
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| − | # Equalize rates in halo counters located in front of the cave back wall
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| − | # Check radiation levels inside the collimator cave
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| − | # Establish possible locations for electronics
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| − | # Check radiation levels in Hall D
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| − | # Check radiation levels in the counting house.
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| − | # Determine suitability of delivering beam into the hall before proceeding.
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| − | ==Location: exiting pair spectrometer==
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| − | # Commission the ladder with the PS converter including the harp
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| − | # Require halo monitors 2 to be installed and operational downstream of the PS
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| − | # Perform a harp scan using the converter ladder
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| − | # Measure intensity and energy distribution of photon beam using pair spectrometer fine and coarse arrays.
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| − | # Determine rate sensitivity to movements of the electron beam on the radiator
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| − | # Check radiation levels inside the collimator cave
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| − | # Check radiation levels inside Hall D
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| − | # Measure single rates of detectors (e.g. BCAL, FCAL, TOF)
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| − | ==Location: behind FCAL==
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| − | # Relocate profile monitor behind the FCAL?
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| − | # Verify expected profile (projection of collimator) through the detector
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| − | # Verify expected photon beam rate
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| − | # Check radiation levels inside Hall D
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| − | # Measure single rates of detectors (e.g. BCAL, FCAL, TOF)
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| − | ==Alignment of beam to target==
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| − | # Install commissioning target and start counter
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| − | # Check that photon beam is transmitted cleanly through target cell
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| − | # Use start counter rates to verify the photon beam is centered on the target
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| − | # Check singles rates of detectors (e.g. BCAL, FCAL, TOF)
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