1. paul drumm, mutac jan 2003 1 1 Status of Muon Beamline design work Kevin Tilley, RAL, 9th Feb Including Beamline Materials in new revision Reference ('True') momenta/materials effects (g4) Basic modelling in TTL & fitting to 'true' g4 effects. Some tentative inclusions in TPT/TTL design codes Status & 'to-do's Thoughts re-examining the Pb-diffuser position Immediate & Future Plans…

2. paul drumm, mutac jan 2003 2 2 Statement of Problem: Beamline Materials SEPT04 Beamline optics & initial momenta designed w/o taking into account effect of materials ie. Vacuum windows, PIDs etc, on beam. μ + central momentum in Tracker1 – design206 MeV/c μ + central momentum in Tracker1 – achieved (g4bl)183 MeV/c hence:- + exist probable further differences ie. MATCHING ('Good Muons'), EMITTANCE etc between design goal & g4bl evaln.

3. paul drumm, mutac jan 2003 3 3 Deduction of correct Initial Muon Momenta's/Material Effects (Thks to KW, using g4bl/g4!) Aimed @ 207.31 after 2x Tkr Planes, for p-ref=200MeV/c Arrive @ Muon source momentum.

4. paul drumm, mutac jan 2003 4 4 Example:- 2" TOF0 eg. TOF0. @ output face of TOF0 (having worked up beamline) find that 242.26MeV/c is required TOF0 output momenta. deduce multiple scattering from ITERATION: INPUT: Iteration shows 253.892MeV/c is rqd input Also: Using input X' rms of 8.26 mrad hence:- Output X'rms = 23.6mrad OUTPUT: Falls to 242.26MeV.c

5. paul drumm, mutac jan 2003 5 5 Hence…Ref set of Beamline Muon Momentas &

6. paul drumm, mutac jan 2003 6 6 Hence…Ref set of Beamline Muon Momentas & Also, performed approx Air split: Q6: 254.041 Q5: 254.352 Q4: 254.663 B2: 255.240 Also, performed approx Air split: Q9: 232.505 Q8: 232.877 Q7: 233.249

7. paul drumm, mutac jan 2003 7 7 and pion channel & pion-momentum Similar process for pions up the pion channel. Calculate pion momentum in centre of DecaySol = 40.5 + 1.5*266.2 = 439.8MeV/c & work backwards… …. in progress … Pion Momentum in Decay Sol = 439.8MeV/c. Arrive @ Pion Momentum at Target.

8. paul drumm, mutac jan 2003 8 8 For including in TPT/TTL:- Include these materials in TTL/TPT, for enabling optics design work…

9. paul drumm, mutac jan 2003 9 9 Example:- 2" TOF0 Basic TTL Model First TTL model. Using g4bl incoming 253.892MeV/c. - Normal density (1.032) -----> both output p-tot out & slightly different from g4bl's TOF0 …. Can vary params to fit to g4bl. Choose only 1: Density, & prioritise fitting delta-p (p-tot out ) INPUT: OUTPUT: p-tot X'

10. paul drumm, mutac jan 2003 10 Example:- 2" TOF0 TTL Model Fit. Fitted TTL model. - New density (0.892) ie. Now p-tot out = 242.252MeV/c. ~ 16.9 mrad (cf. g4bl 22.1mrad) INPUT: OUTPUT: p-tot X' √θ 2 TTL ~ 0.76.√θ 2 g4bl

11. paul drumm, mutac jan 2003 11 In TTL/TPT, a beamline Air block modelled using a collection of 17cm small, high density elements. Needed to split into elements, since TTL/TPT cannot directly model air at same physical location as a magnet. 17cm elements since this also allows placement between Quads/Magnets Taking collection, same fitting process is repeated using density as the variable, to obtain correct p-tot out Example:- Handling Air blocks in TTL/TPT p-tot out = 253.892 INPUT: OUTPUT: √θ 2 TTL ~ √θ 2 g4bl ie. AIRprotAbs->TOF0 ProtAbs TOF0

12. paul drumm, mutac jan 2003 12 Hence…table of ready TTL/TPT materials-fit data

13. paul drumm, mutac jan 2003 13 Illustration of some of the Muon channel materials in TPT:-

14. paul drumm, mutac jan 2003 14 Things still to do re: bl materials revision Complete 'Reference' table –Fix any bugs ( )! –Complete the pion channel. Complete TTL fitting to ref matls data. Criteria: exact Δp, approx, OK ? (Write a MICE-note on above..) Include materials in TPT/TTL & produce the new beamline optics (6π,200MeV/c) Re-Evaluate with G4Beamline ('Good Muons', TOF rates, etc etc.).

15. paul drumm, mutac jan 2003 15 Re-examining the Pb-position: 'How-to' Can make crude re-est. again in TPT/TTL - checking matched ε n for different d But to do properly, use G4MICE/G4BL as well as TPT/TTL :- –New factors (since CERN CM: March'04) :- Better comprehension of ε n ! The presence of the upstream iron detector shield. –The procedure:- Work backwards from matched ε n =10π (or other max) beam with certain preferred Pb position 'p'. Also choose detector shield position as a variable 'd'? Use G4MICE/G4BL. Q: Can beamline supply this beam ? (Use TPT/TTL for quick answer) Re-run above test with different detector shield positions 'd' if needed. If beamline cannot supply beam, bring Pb position 'p' closer to solenoid & repeat until beamline can supply beam. Finish with the

16. paul drumm, mutac jan 2003 16 Immediate & Future Plans/ Wish list (approx in order…) Complete beamline materials revision & evaluation (as described) MICE-note on beamline materials g4/TTL work. Re-examine Pb position ? PAC05 paper! (for May 2005) Matching v Momentum ('beamline abberations') problem. [--> Fix B2 position?] Emittance balancing. Supply ε v = ε h (…=ε n ) Examine various beamline (p,ε n ) cases. Possible beam transport correction schemes. [--> Fix Quads positions?]