2016-Jul-08 Diagnostic Development Biweekly Report

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Kevin Jordan

  • Prepared for and executed High Dynamic Range studies at Rossendorf
  • Worked controls & diagnostics issues on the LERF
  • Continued mentoring my student
  • Working on getting Radiabeam SBIR experiment done on the LERF

Joe Gubeli (see below)

  • Prepared for and executed High Dynamic Range studies at Rossendorf
  • Working own a number of installation issues for Dark Light runs

Mike Tiefenback

  • Time here dealt with ERL proposal comments from TAC and ERL meeting Thursday plus student interactions and my own contributions to these tasks: -Mike Hennessey is following up last year's work on multipass steering and deflection distribution along the linacs. We hope to unravel the quadrupole contribution and understand at what level the derived momentum kick distribution has useful meaning. -Paul Ellison is working on my long-delayed task of review of the (dominantly dipole) "field maps" from magnet measurement. Some clinker points remain after their review process, and the missing points between zero current and 50% full 12 GeV settings result in what might be classed as "questionable results" from naive curve-fitting with simple polynomials. We're investigating the proper form for curve fits and will write up a note detailing the process we define and bounds on interpolation-induced errors from the piecewise linear interpolation the magnet controls use for points between those in the data tables. We expect to supply denser tabular data derived from the curve fits, which will limit the coarse-table artifacts from the interpolation.


    Joe Gubeli - The first week was spent at HZDR where we installed the next generation of both the LDR Imager and fiber coupler optics and tested the LDR with ELBE ebeam. The imager upgrade consisted of an additional mirror and a remote filter wheel. This was necessary to clear obstruction and allow for the mounting of the apodizers. An alignment laser was added that was aligned to the existing ELBE viewers, one before and one after the LDR. The imager optics were aligned to image the alignment laser on the YAG target. The fiber coupling optics were aligned to maximize the reflected light through the fiber with a photodiode. Unfortunately only one wire could be aligned at a time due to a misalignment in the cross assembly. We acquired nearly 1200 YAG viewer images to understand YAG/camera saturation/sensitivity and to gain information on the effects of using apodizers. With an electron beam that was collinear with the alignment laser no OTR was detected from the wire. Clear evidence of the ebeam on the wire was seem with both the current pickup and with a beam loss monitor. The second week several tasks were ongoing. A design for adding a remote way to both exchange apodizers and field stop sizes to the LDR imager was completed. A motor driver was ordered as well as an additional filter wheel. Brian Freeman has taken all the images and has quantified them by background subtraction, fitting them to horizontal and vertical Gaussian curves, summing all the pixels and counting the number of pixels that are above a minimum threshold and the number above a maximum threshold. Marika Whitlatch and I look at the collimating lens for the Happek device and have decided on a simple way to mount it on the viewer girder. Mark Weihl has tapped the necessary holes in that girder. Chris Gould and I looked at adding a viewer to the Darklight Moller chamber. We decided on using an existing insertable device I created for the THz beamline. Chris will start on the modeling next week. Chris also sent out a cost schedule for the three viewer imagers needed at the GTS.