# Difference between revisions of "2018-06-08"

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'''Computational Physics - Y. Roblin''' <br> | '''Computational Physics - Y. Roblin''' <br> | ||

+ | Kirsten Dietrich: | ||

+ | *Last two weeks: | ||

+ | **Magnetized beam (LERF PoP): | ||

+ | *:-trying to correct magnetization damage after FEL booster with off-axis travel through skew quad | ||

+ | *:-trip into LERF vault to locate corrector magnets in current beamline | ||

+ | *:-start trying to quantify magnetization (to better run the optimizer) | ||

+ | **Straight Merger at CBeta: | ||

+ | *:-data analysis (ongoing) | ||

+ | **eCloud: | ||

+ | *:-lit review | ||

+ | *:-email CERN questions related to PyECLOUD results | ||

+ | *:-nag people for codes | ||

+ | *:-generated two main cases (60 GeV CM with stainless steel and NEG-coated) | ||

+ | *:-working on corresponding text for preCDR | ||

+ | **Impedance: | ||

+ | *:-look into kicker count for other machines (feedback (transverse and longitudinal), injection, abort) to add into estimates | ||

+ | **Meetings: | ||

+ | *:-Cooler (x2) | ||

+ | *:-CASA | ||

+ | *:-JLEIC | ||

+ | **Misc: | ||

+ | *:-agreed to act as GPT help for two summer students (minimal) | ||

+ | *Next two weeks: | ||

+ | **Magnetized beam (LERF PoP): | ||

+ | *:-finish quantifying magnetization | ||

+ | *:-run optimizer for 3D FEL booster to fix off-axis/magnetization | ||

+ | **Straight Merger at CBETA: | ||

+ | *:-data analysis | ||

+ | *:-ask George B. about status of field map for coils | ||

+ | *eClould: | ||

+ | *:-calculate tune shift for corresponding densities of eCloud | ||

+ | *:-finish text for preCDR | ||

+ | **Impedance: | ||

+ | *:-add kickers, RF valves into estimates | ||

+ | *:-make best/worst case scenario for electron ring | ||

+ | *:-put out call for presentations for next meeting (June 25) | ||

+ | **Meetings: | ||

+ | *:-Cooler (x2) | ||

+ | *:-JLEIC (x1-2) | ||

+ | *Misc: | ||

+ | *:-Vacation on June 18th | ||

+ | <br> | ||

+ | Yves Roblin: | ||

+ | *CEBAF: | ||

+ | *:-TOSCA versus ELEGANT. writing a note on how to go from one to the other. | ||

+ | *:-2R investigation: Working with J. Benesch to generate the higher order multipoles for all dipoles in the machine using TOSCA models. The idea is to incorporate that into the ELEGANT model. As a first step, I used TOSCA to calculate the same quantity that the 12GeV magnet team used (B'L/BL) and compared with actual measurements provided by K. Bagget. The agreement is good so we are proceeding with using TOSCA to specify the other multipoles (up to decapole). preliminary tracking with multipoles in the S/R magnets qualitatively reproduce features that are commonly seen in the FOPT's. | ||

+ | *:-Worked with M. Tiefenback on optimizing ELEGANT command files for the simulation and use of synchrotron light monitors. Found a few oddities in ELEGANT, working to resolve it. | ||

+ | *:-Met with Thia Keppel, Arne F., D. HigginBotham, M. Tiefenback to find a way to run an Hall A experiment which requires only a few hours of beam at less than 1GeV. We are thinking of running with SL off and also using that opportunity to cross-calibrate ARC1,ARC2 and the hall dipoles strings (1C and 3C). Arne has set aside time the first 2 weeks of August to do the setup in tune mode in order to prepare for the actual experiment (sometimes in november). | ||

+ | *:-Working on transitioning leadership of BTEAM from Todd Satogata to myself. Preparing mid and long term goals up to late 2019. Some of the coming challenges are: several energy changes this year, hyper nuclear end of year requiring low energy spread, next year we will have to deliver parity quality beam at 1 pass while running at 5 pass in other halls. Discussions about this have started. All of this is within the context of a push for model and CED improvements. | ||

+ | *JLEIC: | ||

+ | *:-preparing for the FOA work. First quarter is to implement a higher order tracking in beambeam3d. This will reuse what we already did for GHOST, including the recent work He Zhang has been doing. | ||

+ | *:-continuing pCDR work. | ||

+ | *:-Help C. Tennant to configure his CSR distribution smoothing script on the qcd farm. (on Ops, he could only process 1 million particles, he needs to process in the tens of millions) | ||

+ | *OTHER: | ||

+ | *:-sick leave 6/7, leave 6/8 | ||

+ | <br> | ||

+ | He Zhang: | ||

+ | *Fast multipole method | ||

+ | *:-Used the single level FMM code to solve Yukawa potential problem. The code works as expected. One only needs to revise the kernel function and do not need to change anything else. Then I read a few materials to understand how the Stokes kernel works and I am trying to solve the problem using the FMM code. It looks straightforward, but we need to calculate three kernel functions. Although we can do it one by one, but the proper way is to calculate them all together for better efficiency. Needs some coding to make it happen. | ||

+ | *:-pCDR writing | ||

+ | *:-Did simulations for the low energy DC cooling in the booster and wrote the draft for this section. Polishing the other sections. One more section left: Optimization of the electron cooling efficiency. | ||

+ | *Beam-beam code development | ||

+ | *:-Revise the COSY Script file so that Vasiliy and Balsa can generate high order maps and differential equations from the generating function. Vasiliy suggests finally they want to use MADX to generate the map. But it is not clear how to construct the generating function and the differential equations in MADX. So I wrote c++ code to construct the generating function from the truncated map. The procedure includes (1) read the truncated map from a input file; (2) convert the map into a differential algebra (DA) vector; (3) construct the 2nd kind of generation function (DA vector); (4) construct the differential equations (DA vectors); and (5) convert the differential equations into the “map” data type. Step (3) and (4) include many DA operations, so the TPSA code I wrote previously is used. The code is almost done. Tested with a 4D map, it generates exactly the same generating function with COSY. For the specific 6D map for JLEIC p ring, the generating function of this new code has an extra term “010010” when compared with the one by COSY. The coefficient is at least eight orders smaller than those of other terms. So it may be a numerical phenomena and does not affect the symplectic tracking. This needs to be checked. I will test a few cases before I delivery the code. | ||

+ | *:-As a byproduct, a deeply hidden bug in the TPSA package is founded and fixed. Some new functions are added, such as take derivative of DA vector w.r.t. a base, integrate a DA vector w.r.t. a base, calculate the inverse map of a given DA map. The updates has been pushed to github. | ||

+ | *Work plan in the following two weeks | ||

+ | *:-Continue writing and polishing the pCDR report | ||

+ | *:-Some coding for the kernel-independent FMM | ||

+ | *:-Dust particle transport | ||

+ | *:-Understand the dispersive cooling theory | ||

+ | <br> | ||

+ | |||

+ | |||

+ | |||

## Revision as of 09:22, 11 June 2018

**Director - M. Spata**

*No report.* Acting Accelerator Department Head

**Accelerator Physics - T. Satogata**

Todd Satogata

Previous two weeks (May 28-June 8) - JLEIC: pCDR writing, template, EIC lunch, impedance and R&D meetings - JLEIC: Further organize ICFA beam dynamics newsletter input - ADMIN: Summer student setting in, work planning - ADMIN: Leadership/group meetings, staffing input and planning - ADMIN: CASA group meeting (Jun 6) - ODU: Continue Randy advising, dissertation draft finalization - IPAC18: Finalize proceedings, delegate survey report Next two weeks (June 11-June 22) - JLEIC: pCDR writing, template, EIC lunch, impedance and R&D meetings - JLEIC: Further organize ICFA beam dynamics newsletter input - OPS: TAC review of PAC proposals, transfer BTeam to Yves - ADMIN: Leadership/group meetings, staffing input and planning - ODU: Continue Randy advising, dissertation draft finalization - JACoW: Plan Board of Directors telecon (late June) - ADMIN: HPI Training (Jul 15), Andre Seryi meeting (Jun 18) - ER@CEBAF: Work on coordination of magnet acquisition from Cornell

Alex Bogacz

Previous two weeks (May 28-June 8) - ADMIN: Summer student lecture prep, lecture (June 5) - IPAC18: Light peer review paper final checks and delivery - LHEC: Work on paper on LHeC ERL scaling Next two weeks (June 11-June 22) - ADMIN: Work on talk for muon acceleration - PERLE: Work on talk for PERLE - IPAC18: Submit light peer review papers to IOP for processing

Rui Li

Previous two weeks (May 28-June 8) - JLEIC: Work on pCDR writeup - JLEIC: Calculate ion coupled bunch instability growth rates with new HOM design from Marhauser - JLEIC: Work on ICFA newsletter section on beam dynamics in JLEIC rings Next two weeks (June 11-June 22) - JLEIC: Continue ion coupled bunch instability growth rates with new HOM design from Marhauser - JLEIC: Work on ICFA newsletter section on beam dynamics in JLEIC rings

Ed Nissen

Previous two weeks (May 28-June 8) - ADMIN: Summer student setting in, work planning, reading up on pyORBIT - JLEIC: Continue Booster acceleration simulations - JLEIC: Continue booster nonlinear optimization work - JLEIC: Finish draft writing for pCDR for Booster section Next two weeks (June 11-June 22) - JLEIC: Polishing presentation for LDRD committee, presentation - JLEIC: pCDR Booster consistency updates - JLEIC: Start looking at Booster injection design with summer student

Chris Tennant

Previous two weeks (May 28-June 8) - JLEIC: investigate effect of using 2x longer bunch in CCR - JLEIC: begin pushing a realistic (via Fay) bunch through ERL driver of CCR and assess performance (i.e. will it make it around the first arc, let alone make it to the CCR?) - PERLE: Vlasov and elegant tracking to get uBI gain in PERLE first pass Next two weeks (June 11-June 22) - JLEIC: Work with Dave to sort out CCR beam exchange - JLEIC: Input distribution from Fay for ERL tracking (and CCR?) - LERF: Read up on documents related to being LERF APEL

**Accelerator R & D - Y. Zhang**

**Computational Physics - Y. Roblin**

Kirsten Dietrich:

- Last two weeks:
- Magnetized beam (LERF PoP):

- -trying to correct magnetization damage after FEL booster with off-axis travel through skew quad
- -trip into LERF vault to locate corrector magnets in current beamline
- -start trying to quantify magnetization (to better run the optimizer)

- Straight Merger at CBeta:

- -data analysis (ongoing)

- eCloud:

- -lit review
- -email CERN questions related to PyECLOUD results
- -nag people for codes
- -generated two main cases (60 GeV CM with stainless steel and NEG-coated)
- -working on corresponding text for preCDR

- Impedance:

- -look into kicker count for other machines (feedback (transverse and longitudinal), injection, abort) to add into estimates

- Meetings:

- -Cooler (x2)
- -CASA
- -JLEIC

- Misc:

- -agreed to act as GPT help for two summer students (minimal)

- Next two weeks:
- Magnetized beam (LERF PoP):

- -finish quantifying magnetization
- -run optimizer for 3D FEL booster to fix off-axis/magnetization

- Straight Merger at CBETA:

- -data analysis
- -ask George B. about status of field map for coils

- eClould:
- -calculate tune shift for corresponding densities of eCloud
- -finish text for preCDR

- Impedance:

- -add kickers, RF valves into estimates
- -make best/worst case scenario for electron ring
- -put out call for presentations for next meeting (June 25)

- Meetings:

- -Cooler (x2)
- -JLEIC (x1-2)

- Misc:
- -Vacation on June 18th

Yves Roblin:

- CEBAF:
- -TOSCA versus ELEGANT. writing a note on how to go from one to the other.
- -2R investigation: Working with J. Benesch to generate the higher order multipoles for all dipoles in the machine using TOSCA models. The idea is to incorporate that into the ELEGANT model. As a first step, I used TOSCA to calculate the same quantity that the 12GeV magnet team used (B'L/BL) and compared with actual measurements provided by K. Bagget. The agreement is good so we are proceeding with using TOSCA to specify the other multipoles (up to decapole). preliminary tracking with multipoles in the S/R magnets qualitatively reproduce features that are commonly seen in the FOPT's.
- -Worked with M. Tiefenback on optimizing ELEGANT command files for the simulation and use of synchrotron light monitors. Found a few oddities in ELEGANT, working to resolve it.
- -Met with Thia Keppel, Arne F., D. HigginBotham, M. Tiefenback to find a way to run an Hall A experiment which requires only a few hours of beam at less than 1GeV. We are thinking of running with SL off and also using that opportunity to cross-calibrate ARC1,ARC2 and the hall dipoles strings (1C and 3C). Arne has set aside time the first 2 weeks of August to do the setup in tune mode in order to prepare for the actual experiment (sometimes in november).
- -Working on transitioning leadership of BTEAM from Todd Satogata to myself. Preparing mid and long term goals up to late 2019. Some of the coming challenges are: several energy changes this year, hyper nuclear end of year requiring low energy spread, next year we will have to deliver parity quality beam at 1 pass while running at 5 pass in other halls. Discussions about this have started. All of this is within the context of a push for model and CED improvements.

- JLEIC:
- -preparing for the FOA work. First quarter is to implement a higher order tracking in beambeam3d. This will reuse what we already did for GHOST, including the recent work He Zhang has been doing.
- -continuing pCDR work.
- -Help C. Tennant to configure his CSR distribution smoothing script on the qcd farm. (on Ops, he could only process 1 million particles, he needs to process in the tens of millions)

- OTHER:
- -sick leave 6/7, leave 6/8

He Zhang:

- Fast multipole method
- -Used the single level FMM code to solve Yukawa potential problem. The code works as expected. One only needs to revise the kernel function and do not need to change anything else. Then I read a few materials to understand how the Stokes kernel works and I am trying to solve the problem using the FMM code. It looks straightforward, but we need to calculate three kernel functions. Although we can do it one by one, but the proper way is to calculate them all together for better efficiency. Needs some coding to make it happen.
- -pCDR writing
- -Did simulations for the low energy DC cooling in the booster and wrote the draft for this section. Polishing the other sections. One more section left: Optimization of the electron cooling efficiency.

- Beam-beam code development
- -Revise the COSY Script file so that Vasiliy and Balsa can generate high order maps and differential equations from the generating function. Vasiliy suggests finally they want to use MADX to generate the map. But it is not clear how to construct the generating function and the differential equations in MADX. So I wrote c++ code to construct the generating function from the truncated map. The procedure includes (1) read the truncated map from a input file; (2) convert the map into a differential algebra (DA) vector; (3) construct the 2nd kind of generation function (DA vector); (4) construct the differential equations (DA vectors); and (5) convert the differential equations into the “map” data type. Step (3) and (4) include many DA operations, so the TPSA code I wrote previously is used. The code is almost done. Tested with a 4D map, it generates exactly the same generating function with COSY. For the specific 6D map for JLEIC p ring, the generating function of this new code has an extra term “010010” when compared with the one by COSY. The coefficient is at least eight orders smaller than those of other terms. So it may be a numerical phenomena and does not affect the symplectic tracking. This needs to be checked. I will test a few cases before I delivery the code.
- -As a byproduct, a deeply hidden bug in the TPSA package is founded and fixed. Some new functions are added, such as take derivative of DA vector w.r.t. a base, integrate a DA vector w.r.t. a base, calculate the inverse map of a given DA map. The updates has been pushed to github.

- Work plan in the following two weeks
- -Continue writing and polishing the pCDR report
- -Some coding for the kernel-independent FMM
- -Dust particle transport
- -Understand the dispersive cooling theory

**Diagnostic Development - K. Jordan**

**LERF - S. Benson**