2015-08-07 Diagnostic Development Biweekly Report

CASA Diagnostic Develipment
Biweekly Report: 07/25/15 - 08/07/15
Submitted by: Pavel Evtushenko

Michael Tiefenback

1. Closeout of REU/SULI student work for Michael Hennessey (plus Alex Mack under Ed Daly's supervision -- see 3 below)
   1. paper review and edits,
   2. preparation for TN documenting work to date
   3. discussion and planning for upcoming experimental measurements in CEBAF.
      In following up on this work, I realized that it overlaps with BNL Energy Recovery. The final pass decelerating beam will be unpleasantly messy regarding steering and focusing unless we have compensated for skew fields (RF effect, sign-inverted from the usual CEBAF state for deceleration) and cavity deflections (also sign-inverted on deceleration). It appears that we may want to align the linac(s) for the decelerating beam and suffer the misalignments on the accelerating side.
      
      A clean experimental separation may be possible for transverse momentum kicks along each linac due to geomagnetic, quadrupole offset induced, and RF cavity alignment effects. This is somewhat complicated by the present coarse alignment of skew quadrupole compensation coils.

   
   

2. BNL Energy Recovery work
   Diagnostic planning and layout -- investigate solutions for emittance measurements
   1. in arcs with supplemental SLMs
   2. in Extraction regions near dogleg chicane quadrupoles with multiple wire scanners

   
   

3. Further library search for hot-wire anemometry as mass-flow diagnostic. I am also investigating computational tools to help me engage myself in this. This physical principle is being exploited to make liquid hydrogen flow-meters, as well as gaseous and liquid cryogenic helium systems. Successful development should provide measurements of heat evolution into the cryomodule LHe reservoirs on a time scale of seconds. This will potentially enable Q0 measurements as a function of gradient with measurement durations in minutes instead of hours. Such measurements may be possible for 4K operation as well as 2K operation, and results should help guide us in devising ways to use opportunistically available 4K accelerator time.

Pavel Evtushenko

1. Made final edits and presented short talk at the Lab's S&T review.
   
2. Made first evaluation/test measurements of the new chassis with 936 MHz backup oscillator, the chassis was built by Tomasz Plawski and Rama Bachimanchi, and will be used for synchronization of the laser-wire laser system with the beam at ELBE facility. In our new approach, the laser will be synchronized directly to the beam and not to the RF system of the accelerator. More detailed measurements with the chassis will be done within next two weeks.
   
3. Most of the time last two weeks was spent at HZDR, ELBE facility. Joe Gubeli and Mike Spata also visited HZDR.
   
4. During the visit we have discussed continuation and extenuation of the existing CRADA between JLab and HZDR in the field of beam diagnostics. Preliminary text of an addendum tot he CRADA was compiled and is being reviewed now.
   
5. We have done a large number of measurements with beam, while continue commissioning new in vacuum Martin-Puplet interferometer designed and build for ELBE at HZDR for bunch length measurements. We have also worked on the further development of the system i.e. a new dedicated DAQ system, of which first iteration was completed and tested with beam.
   
6. We have recommissioned the laser system installed at ELBE for the laser-wire project. While doing this we have found a number of inconsistent things with the system shutter operations, yet we were able to run the laser system at it full specs and cross check all laser parameters. We have installed and commissioned all of our laser instrumentation need to check and monitor laser beam parameters, which was used to do all of our laser beam measurements.
   
7. We have also discussed the possibility of installation of one of our LDR viewer and wire-scanner diagnostic stations at ELBE with the goal to have more of the beam time available for experimental tests. We found a very good place at the ELBE facility where the diagnostic station can be installed, and work now on the plans to move one of the stations to the ELBE.