Beamline Optics meeting, 12:30 BST (06:30 Fermilab).
31st May 2006
Present: KT, PD, KL
Phone: CR, TJR, KW
Notes added at time of meeting in green.
Agenda.
1) Notes/Actions from 2006-05-31
(see attached overleaf from 31st May meeting)
2) Status of work
- G4BL Evaluations
- Tom described the results of his evaluation of cm14-7.1-200. The presentation can be found under CM14-7.1pi-200-TJR.ppt.
- Rates had been found to be 3.6MHz at TOF0 and Good muons 1049/msec. This could allow shallower target dip, reducing TOF0 rate -> 2.1MHz @ 600 Good muons/msec. The emittance calculation algorithm had been reviewed. In brief: +/-10% cut on Ptot, hit in all Tracker 1 stations. The resulting emittance was found to be 11.7pi mm rad for this design of 7.1pi mm rad. Beta averaged ~ 0.38m but both beta and alpha showed notable variation in the tracker (unmatched).
- KW described his results. Work had extended to evaluate cm14 1,7.1 and 10-200 optics. Cm14-7.1-200 had TOF0 rate of 3.6MHz (=TJR result), 0.9MHz Good muons. Cm14-10-200 showed TOF0 rate of 3.3MHz, 0.7MHz Good muons. The data cuts were being implemented prior to completing the emittance evaluation.
- Optimisation plans.
- KW had applied his optimiser against his cm14-7.1-200 case. It had reduced beta from 452mm to 388mm although the emittance he had had increased from 11.2 -> 12.4 pi mm rad.
- aob
- The aperture of B1 had reduced since the distribution of the CM14….xls spreadsheet. The thickness of the u/stream vacuum tube had also received some engineering design. This should be folded in more formally later on.
3) EPAC06 paper (www.epac06.org)
- It was recognised that there were a many pressures competing with the EPAC06 paper! The upcoming request was still for a draft from each of the authors by the 7th June though! (KT,KW,TJR)
4) Beamline Review (PD/ALL)
Monday 12th June
For aim and scope see:- http://www.isis.rl.ac.uk/accelerator/MICE/TechBoard/D&S/2006-06-12%20Beamline/Index.html
The following Review agenda was proposed:-
Intro: PD
Tranport/Turtle:KT
Simulation:TJR/KW
Engineering:PD
Summary:?
Ideally, we should aim to distribute the documentation for the review by Monday 5th June. In view of TJRs commitments, it was agreed that Kenny would update the Performance section of the TRD. (KW)
We should also ideally have a draft of our talks ready for the beamline session on the 9th June. (ALL)
5) General CM15 Talks?
6) AOB
Ken Long outlined the issues which could limit the maximum tracker readout rate. If backgrounds were a problem, this could reduce the maximum rate. For the present however, we should continue to aim to furnish 600 Good muons per second.
Yagmur would be asked to advertise our meetings and help with setting up a MICE phone conference?. (PD to ask YT after CM15)
7) Next meeting – 9th June @ FNAL!
What / Who / When / CommentOptics for full range of emittances and energies
(worst cases in priority)
1, 6 10 pi for 200MeV/c in turtle
PD/KT to review data on web (and link from MICE-UK). Done
240 MeV by scaling (KT) : Rates (TJR/KW). Not yet done – note the 240/10pi case overshoots the 5Tesla Sol field. A new optic is needed (KT/DJA)
140 MeV by scaling (KT) with a scaled spectrometer fields: 140/200*4T; b=known (333) ; This would be the first stage, then a new optic would be needed.
Collimation positions need to be added
Position of absorber needs to be changed?
The absorber position was kept at B2 upstream face for the present.
Optimiser 6pi@200MeV/c : (KW)
TJR: 10pi
1 pi is 6pi with collimation (needs G4BL)
Naming convention: CM#-e-p,
e.g. CM14-1-200 / Beam line team
Dean Adams
Kevin Tilley / VC 12 April / High Priority, must be sure beam line delivers before design and location of correctors collimators and magnets is fixed.
review is planned end of April!
orbit correction and collimators
PD: positions & sizes of steering dipoles
PD: find info on CKOV1
PD: TS1 steerers? / “ / VC 12 April
diffuser mechanism
CR: current diameter of diffuser: 20cm: is this ok for 10pi? CR: 30cm is better to understand the scraping? Should be ok for beam line. Could be a special plate?
It would be nice to have a position on this by CM15. This is still a hot potato! WL’s slides from CM14 indicate redesign of holder might allow a slight increase in diameter? CR/TJR should produce a basic analysis/case for increasing >20cm ie: what we currently ‘get’ @ 20cm, what we loose @ 20cm.(CR/TJR for CM15) / W. Lau &
S. Wang / was reviewed at CM14.
VC in May
Define number of thicknesses
CR: is 6 enough? TJR & KW also to look at this? It would be nice to have a position on this by CM15. The number of slots (6) in the current design would be taken as acceptable, unless we discovered issues with this latterly. Changing the carousel can of course easily make other thickness’ available. / Chris Rogers / CM 15 / try to see what can be done with 5 thicknesses and correct if needed
Validate 200 mm clear diam. for diffuser mechanism / Long ð CR / VC 29 March
Generate standard G4MICE files ( continue as now generate G4BL files) / Beam line group + Yagmur Torun / CM15 / need one or two to start with!
Investigate matching to different solenoid fields rather than fixed 4 T (natural extension of fixed field solenoid) / low priority
Understand what happens to collimated particles: G4BL
Explore use of collimators, e.g., for pencil beam: To be done
Explore use of ISIS target station 2 correctors
—can we piggyback on their order?
No, but other alternatives
Define tolerances (alignment, field strength, field quality) for all elements
Standard beam alignment
Field quality could be measured
Build procedure needed (KW/PS/PD)
Develop optimizer for beam line design
Multiple points for fitting?
Maximum field gradients (PD)
Group review at CM15
Define diagnostic needs for beam line
Ongoing: include in build procedure
Outstanding New Actions from 2006-05-17 and 2006-05-31 :-
2) Data Organisation
A data template was proposed to hold standard G4BL data. Discussion suggested removing the particle ID plot, all downstream detector plots, and include beta/alpha in Tracker 1. It would be reissued. Done. The data template should also include the 6x6 covariance matrix within the Tracker, and beta & alpha at Absorber1. It would be reissued again! (KT).
A data template for Turtle data was to be issued (KT)
3) G4BL Evaluations
- It was suggested that thoughts could be given to looking at TOF0 collimation in G4BL (KW). Also, a means of producing a pencil beam for MICE alignment could be investigated (KW).
5) Beamline Review
- Documentation should be made available 1week before the day (eg. TRD update desirable) (ALL)
- A look at the realism of our G4BL/Turtle simulations could be ie. one example being fringe fields from elements. (KT,KW)