Director (M. Spata)
Accelerator Physics (T. Satogata) Todd Satogata
Previous two weeks (Sep 18-Sep 29) - ADMIN: Appraisal training (Sep 19) - OPS: BTeam (Sep 19), ATLis cleanup, troubleshooting guide, RSR accounting - IPAC18: invited program finalization, registration opening - JLEIC: Continue assembling documents, pCDR meetings/planning - JLEIC: Continued esme simulations for coasting beam instability evaluation - ODU: USPAS January 2018 class coordination (registration opening) - ADMIN: Write recommendation letter for Eric Thompson Fulbright application - ODU: JMU seminar prep/trip (Sep 29) Next two weeks (Oct 2-Oct 13) - PERS: Wish Mike a Happy Birthday (Oct 2) - OPS: BTeam (Oct 3), ATLis cleanup, ORFP update review - OPS: 12 GeV beam parameter meeting - JLEIC: Prepare talk for BNL collaboration meeting - ADMIN: Peer review NIM paper - IPAC18: Editorial board meet (Oct 5), SPMS support work - JACOW: Team Meeting travel planning, organization - JLEIC: Continue assembling documents, pCDR meetings/planning - HALLD: Help McCaughan prepare slides for GlueX collab meet talk (Oct 12) - JLEIC: Collaboration Meeting (Oct 9-13)
Previous two weeks (Sep 18-Sep 29) - NUFACT: NUFACT'17, talk on "Muon Acceleration for Neutrino Factory and Beyond" - IPAC18: Continue APS scientific publication board org for light peer review - ADMIN: Invention disclosure review, TRC work Next two weeks (Oct 2-Oct 13) - ADMIN: Peer review PRAB paper - NUFACT: Write, finish paper for NUFACT'17 proceedings - USPAS: Continue work on lectures for "Practical Accelerator Design"
Previous two weeks (Sep 18-Sep 29) - JLEIC: More work beating on tilted solenoid, comparison to DIMAD - JLEIC: Work on talk for EIC collaboration meeting - JLEIC: respond to any results Chris develops on the simple CCR arcs (and started write up the simple arc) - JLEIC: Work with Chris to understand Bmad quadrupole model - ADMIN: Neil symposium (Sep 27) Next two weeks (Oct 2-Oct 13) - JLEIC: continue with tilted solenoid: generate transfer matrix (numerical differentiation); start comparing to conventional modeling - JLEIC: continue responding to any results Chris develops on the simple CCR arcs and writing up the simple arc - ADMIN: talks for collaboration meeting, Bonn, and Daresbury
Previous two weeks (Sep 18-Sep 29) - JLEIC: prepare slides summarizing my understanding of electron cloud in JLEIC and present at R&D meeting - JLEIC: start to work on slides summarizing JLEIC collective effects for the upcoming collaboration meeting in BNL - ADMIN: continue to work on matters for the thesis award committee (deadline is 9/16) - ADMIN: Write recommendation letter for Eric Thompson Fulbright application - VACATION: Sep 22 - ADMIN: Neil symposium (Sep 27) Next two weeks (Oct 2-Oct 13) - VACATION: Oct 2-3 - JLEIC: Prepare slides on collective effects for EIC collab meet - JLEIC: Collaboration Meeting (Oct 9-13)
Previous two weeks (Sep 18-Sep 29) - JLEIC: chasing down issues around injection problems in the booster, and we determined that there may be dispersion in sections that are not dispersive. - ADMIN: Neil symposium (Sep 27) Next two weeks (Oct 2-Oct 13) - JLEIC: figure out the best way of combatting injection synchrobetatron coupling and hopefully get a good injection simulation going. - VACATION: Oct 9
Previous two weeks (Sep 18-Sep 29) - JLEIC: trying to benchmark Bmad for a single quad (elegant and DIMAD agree but use the same phase space coordinates while Bmad does not; tried (with Dave's help and a 30+ year old TN he wrote) to do the appropriate transformations. Still not making sense) - PERLE: learning/trouble-shooting Cheng-Ying's code for use with acceleration (to model S2E PERLE lattice) - JLEIC: summarizing results from analysis of CCR "simple arc" (microbunching is under control, one pass through arc is okay, 10 passes through a ring comprised of arc and we're doomed - CSR longitudinal wake induced energy spread growth/distortion and CSR-generated emittance growth) - ADMIN: Neil symposium (Sep 27) Next two weeks (Oct 2-Oct 13) - CRADA signed? (a talk at the symposium raised the possibility of renewed interest in FEL for Navy and/or lithography in 2025 time frame - woot!) - JLEIC: resolve Bmad issue and proceed to play with CSR/CSR shielding capabilities (benchmarking with elegant if possible) - PERLE: proceed with PERL analysis - really need some results for multiple turns. Suspect they are doomed too.
Previous two weeks (Sep 18-Sep 29) - Dissertation writing: Continue coasting beam chapter, tech note Next two weeks (Oct 2-Oct 13) - Dissertation writing: Hopefully coasting beam chapter, tech note
Accelerator R and D (Y. Zhang)
- Presented the progress on the study of the chromaticity compensation and dynamic aperture in the electron collider ring and discussed the design tasks of electron collider ring in the bi-weekly non-linear dynamics meeting.
- Redesigned the detector region optics in the electron collider ring and compensated the coupling effect due to the detector solenoid.
- Working on the presentation for the EIC collaboration meeting at BNL.
- Miscellaneous: discussion of spin tracking with Dave Sagan, attended the JLEIC R&D meeting, attended JLEIC parameter coordination meeting, attended JLEIC simulation plan meeting, attended JLEIC detector meeting.
- Geometry tagging LDRD: simulations, data analysis, setting up for the next year
- Ion polarization: simulation of crab crossing effect on the ion polarization, teleconference with Anatoliy's group, DSPIN'17 paper
- Collider ring design: teleconference with SLAC, work planning
- Interaction region design: iteration on the magnet and correcting element design
- Lower-effort activities: crab crossing, planning of JLEIC R&D, seminar committee
- Ran GEMC simulations for the geometry tagging LDRD project. Placed a virtual detector in the model for the interaction region - virtual detector was placed just beyond the final quadrupole of the downstream ion quadrupole triplet to tag all particles that pass through the quad triplet.
- Analyzed detected particles from GEMC simulations. Wrote python script to format GEMC output for conversion to root files for plotting. Generated plots of neutron multiplicity, proton multiplicity, change in rigidity, and a of residual nucleus vs nuclear thickness of the reaction.
- Attended COOL'17 workshop and gave a talk, discussed with cooling experts
- Gave a presentation on the topic of update of staged cooling scheme at the weekly JLEIC Accelerator Meeting
- Attended Neil Symposium
- Started study of JLEIC DC cooler
- Completed organization of EIC Accelerator Collaboration Meeting
Computational Physics (Y. Roblin)
Yves Roblin Working on beam beam simulations:
- Studied the effect of the proton synchroton tune on luminosity and its implications regarding the needed voltage
- Implemented conversion from mad-x ptc to bb3d for the higher order transfer matrices, found a bug in bb3d regarding the treatment of matrices.
- Dynamical beta studies. Theory and simulations match with an overall 1.27 factor (not sure why yet..)
Preparing for the collaboration meeting:
- Made most slides.
- Organizing simulation efforts with a target of march-april delivery for pCDR.
- Meeting last Friday, proposed the timeline, got feedback, will publish it soon.
- Amy will be looking the feedback systems for JLEIC, determining and writing specifications for it.
Next two weeks:
- Finish the slides for the collaboration meeting
- Attend collaboration meeting
- Start the non-linear studies for the beambeam
- Restart GHOST meetings (10/03 is the restart)
- Look into the status of GPT. Reports are that what was delivered does not have the CSR module..
I am working on analysis of Beam-Beam interactions with a crossing angle in last two weeks. We have clarified the details of Lorentz boost. The relations between the accelerator frames has been studied as well. Next week we will focus on the Beam-Beam force (Hamiltonian) in a new "head-on" frame where Lie algebra will be used to decribes the interactions of the beam-slices.
- Cooling simulation for JLEIC - Discussed with Jiquan how to maintain the bunch length unchanged during cooling. Jiquan suggests reducing the RF voltage as the ion beam momentum spread reduces. Jiquan told me they prefer a constant ion bunch length during injection to make sure the space charge shift will not be too large. For cooling, a constant ion bunch length helps to mitigate the over cooling in the longitudinal direction. We proposed to first (1) simulate the cooling with the ion bunch length fixed artificially to know how the momentum spread changes, then Jiquan could (2) check how the RF voltage should be adjusted, and finally (3) we combine the varying RF with cooling simulation to confirm the idea. A simulation of (1) for DC cooling on the proton beam during injection has been done. But I haven’t present the result to Jiquan.
- Model of the electron beam space charge in cooling simulation - I am still working on the formulas. There is one formula of the transverse velocity drift due to the space charge field for electron beam that I have not fully understand. Actually I have understand the same formula in Poth’s paper and in Parkhamchuk’s paper. However, BETACOOL is using a different one with a different coefficient. (There is also a different coefficient between BETACOOL manual and its code.) I need to dig a little deeper. BETACOOL is not necessarily wrong. It probably uses a different definition. We also suspect the edge of the bunched electron beam in IMP experiment has velocity drift due to longitudinal space charge field. I cannot find a reference on it. So I derived the maximum change of momentum for the edge based on a simple model.
- DA based FMM - Tried to extend the DA based FMM from 1/r kernel to other kernels. Using some tricks, I can extend it to the following kernels: 1/rn, rn, ln(rn), exp(r), or exp(-r). However, the following kernels I tried but failed: exp(-r2), error function, 1st and 2nd kind modified Bessel function.
Also tried to extend the DA based FMM to Taylor model (TM) based FMM. The later will not only calculate the expansion but also given a rigorous error bound. However, I got stuck on how to compose two TM vectors. Not being able to figure out how to do it after reading papers, COSY manual, and trying test codes, I sent an email to Prof. Berz for help.
- Paper on heat load and trip rate optimization - Finished the paper.
- Others: Reviewed three papers. Two for Signal, Image and Video Processing, and one for Journal of radiotherapy in Practice. Discuss with River about luminosity calculation for crab crossing.
Next two weeks work plan:
- Prepare the talk for EIC collaboration meeting and attend the meeting
- Continue developing the turn-by-turn tracking for IMP experiment
- Continue developing the space charge model for cooling
- Reading: ERL mergers, CSR in GPT and ERL mergers, RTFB transforms, wakefields/impedance
- Simulations: chicanes in GPT (compared to elegant), field maps from Fay for GTS gun, FEL injector components
- Meetings: FOA R&D related to CCR, JLEIC, High Power FEL Symposium
- Simulation tools: attempting to find Bas's CSR module for GPT, attempting to obtain KEK's shielded CSR module for GPT (probably successful), was some investigation into possible shielded CSR in Parmela by Jorg Kewisch at BNL (didn't exist)
- Misc: USPAS acceptance came through
Next two weeks:
- Reading: wakefields/impedance, shielded CSR calculations
- Simulations: get UITF (new CEBAF quarter cryomodule) unit field maps from Haipeng, magnetized beam from GTS gun through FEL buncher and FEL/UITF booster, vary charge and bunch length, particularly concerned with keeping beam magnetized and size, above through existing merger, if magnetization is kept.
- Misc: fill out forms to get USPAS paid for
- Meetings: Simulations, JLEIC, Cooler?
Diagnostic Development (K. Jordan)
- Completed and submitted Preliminary Safety Assessment for LCLS-II CM testing project
- Updated www.faraday-cup.com website for upcoming conference
- Had a new wiki page created for LCLS-II documents - wiki.jlab.org/lerf
- Had another kick-off meeting - this time for EHS&Q
- Met with Rusty & facilities for LERF building changes
- Working on ODU/IU proposal with Hari & Geoff
- Prepared talk & attended George's FEL symposium
- Worked on solution for LCLS-II waveguide layout
- Attended George's symopsium
- Packed up lab L307 for moving to LERF
- He attended the High-Power FEL symposium for George Neil on Wednesday
- He has been conferring a bit with Jay on a septum-like kind of magnet, one much cheaper to make than our tightly spaced septum magnets. This might be, for instance, a replacement for the YB magnet in the "B" spreader, peeling the Hall D beam off the bottom of the stack of beams. Some of this happened in the previous biweekly period, but as I seem not to have mentioned it, I thought I would do so here. The septum magnets use a "current sheet" coil layout at one side of a pole-tip pair to terminate the bending field with minimal field distortion, allowing closer spacing of the beams in the bending segment and in the field-free segment. It may be possible to make much cheaper septum magnet systems in the future, less vulnerable to thermally induced stress cracks.
- Speaking of which, we here at JLab are exposed to the very real prospect of having our long-in-use septum magnets develop spontaneous leaks as a result of cumulative thermal cycling. They have a very high cooling water temperature rise in typical use. I have been told that one of the septa developed a spontaneous water leak not terribly long ago. This makes me nervous.
- He started conferring with Sarin Philip and the magnet crowd on an insertable Hall probe fixture allowing confident and coarsely quantitative assessment of quadrupole field profiles in situ in the tunnel. This looks interesting to me, and would be a boon to anyone working on magnets in-tunnel and needing to be absolutely confident after buttoning everything back up that it is still correctly connected. I could cite a 3A quadrupole incident supporting this. They didn't involve me on the mechanical design concept for this, and I'm concerned about how well the approach they described will work in real life.
- He is also making the first stages of feeling about for whether a refractive X-ray lens can be acquired to test direct X-ray SR imaging in 1C12 and 3C12. This would by-pass any diffractive limitations at optical wavelengths, making our SLM-based energy spread bounds more confident and more precise. Again, this is targeted at such things as the reprise of the hypernuclear runs looking like they will occur a year from now. Getting set up in parallel with Gubeli in one of the LERF labs for resolution improvement tests at optical wavelengths is also an interesting and useful thing I'm trying to get going.
LERF (S. Benson)