[BTeam] draft TN on BSY dump

[Michael Tiefenback]

I would perhaps modify/add that the lack of use of the BSY dump was due, in my perception, to the difficulty of setup of the required raster configuration with its requirement of special visual setup, coupled with its either/or relationship with first Hall B beam and later Hall C beam.  There were difficulties of perceived machine safety and radiation ALARA considerations when directing "tune mode" beam to Hall or Arc dumplets coincident with CW beam to experimental halls.  Operationally, we "tip-toed" around these things in a less than best-efficiency fashion, but generally delivered adequate beam to our users.  Other alternate and no-less-valid opinions may exist.

I would have preferred to preserve the BSY dump, but Jay's cost estimates argue persuasively that it is not the best investment of resources.  Moving magents in and out for measurement seems to me to be a non-inssue.  Concerning magnet mapping, there appears to me to be no critical need for precise BDL[I] measurements for BSY dump magnets, as no precision requirement exists for them.  The principal (only?) requirement is to direct beam onto the dump face in a hardware-safe manner.  Core field (via NMR) measurements coupled with the existing field maps provides effective length characterization, and B_central vs. current can be simply measured in situ.  If too great uncertainty were found, siting viewers (even temporarily) to determine when beam is on beampipe center would provide adequate validation.  Similarly, no requrement exists for the H steel to be monolithic.  It carries no (significant) longitudinal flux (other than accidentally, mostly to support the slight effective length end flux) and can be installed in bits and pieces.  Moving a long (4-meter) dipole into place is a much greater matter.

Just my thoughts, for what they're worth for any future parallel considerations.

Michael Tiefenback

________________________________
From: BTeam <bteam-bounces at jlab.org> on behalf of Jay Benesch <benesch at jlab.org>
Sent: Tuesday, January 5, 2021 17:38
To: bteam at jlab.org <bteam at jlab.org>
Subject: [BTeam] draft TN on BSY dump

Attached find the first draft of a TN documenting the decision to decommission the BSY dump.  Edit the odt file directly or send me changes.
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