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m. apollonio

Beam-Line Analysis. m. apollonio. 1. MC (G4Beamline). DATA. M0 10-240. MC (G4Beamline). DATA. M1 10-240. Characterizing the BL  MATRIX. Intensive Program (started in June with CR as MoM) Choose Range of Momenta  initial optics: M 0

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m. apollonio

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  1. Beam-Line Analysis m. apollonio CM27 - RAL 1

  2. MC (G4Beamline) DATA M0 10-240 CM27 - RAL

  3. MC (G4Beamline) DATA M1 10-240 CM27 - RAL

  4. CM27 - RAL

  5. Characterizing the BL  MATRIX • Intensive Program (started in June with CR as MoM) • Choose Range of Momenta  initial optics: M0 • scan of the DS triplets (and single Q4,..Q9) for some relevant optics • define variation of Twiss Parameters as a function of optics • MC simulation • DATA Analysis • Comparison • Optimize M0 Mopt: awesome or awful? • DATA Analysis (*) 700mV ~ 20 mu-/spill CM27 - RAL 5

  6. The BL can be thought as constituted by TWO blocks: • US (=PIONS) and DS (=MUONS) • BL momentum scale is a pair of values • (P0 = momentum at target, PSol= momentum at Decay Solenoid exit, or D2) • P0 defines the momentum scale for PIONS • PSol defines the momentum scale for MUONS • Momentum scale(s) must match the US Diffuser face values •  initial optics: M0 • easy, once defined Pdif we can work back Psol and P0 through • the tables. However the Twiss parameters at Diffuser are “random” • Recall also the main philosophy in defining (P0, Psol) • select Psol such that BACKWARD GOING muons are captured • so increase PURITY CM27 - RAL

  7. m kinematic limits 6-240 409 MeV/c 350 MeV/c m @ the Dksol exit (G4Beamline) 238 MeV/c 10-240 6-200 195 MeV/c CM27 - RAL

  8. 3,140 Pdif=151 a=0.2 b=0.56m t=0.0mm 3,200 Pdif=207 a=0.1 b=0.36m t=0.0mm 3,240 Pdif=245 a=0.1 b=0.42m t=0.0mm 6,140 Pdif=148 a=0.3 b=1.13m t=5.0 6,240 Pdif=256 a=0.2 b=0.8m t=7.5mm 6,200 Pdif=215 a=0.2 b=0.78m t=7.5mm 10,140 Pdif=164 a=0.6 b=1.98m t=10mm 10,200 Pdif=229 a=0.4 b=1.31m t=15.5mm 10,240 Pdif=267 a=0.3 b=1.29m t=15.5mm CM27 - RAL

  9. P (MeV/c) • finding the element (3,240) means to find the BL optics that matches the MICE optics for a beam of 3 mm rad at a P=240 MeV/c 3,140 3,200 3,240 6,140 6,200 6,240 eN (mm rad) • the element (10,200) is the BL optics matching a MICE beam with 10 mm rad at P=200 MeV/c 10,140 10,200 10,240 This pair is our goal: how do we get it? CM27 - RAL 9 (*) 700mV ~ 20 mu-/spill

  10. Hyp.: eN0 is known (~1 mm rad trace space) • we proceed backward: • fix P/eN in the cooling channel • fix the optics in the cooling channel (a3,b3) • solve the equations giving a,b and t at the US face of the diffuser (*) b0 a0 Diffuser b1 a1 b2 a2 b3 a3 t BL MICE e1 (*) MICE note 176 e0 CM27 - RAL 10

  11. So the question becomes: • how do we “tell” the beamline to be a0, b0 at US_Diff? • solution(s) • we optimise the BL by varying Q4-Q9 • let us break the BL in two parts: US and DS • in what follows I mean a p m beamline Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Dipole1 Dipole2 DK solenoid • DS part: • choose Q4-Q9 • shoot a beam • check a,b at Diffuser vs “target” values • repeat m p • US part: we can optimise the MAX number of pions • but not much magic left … CM27 - RAL 11

  12. p m beam line: typical m spectrum at the exit of the DS • Rationale • select p u.s. of DKSol with D1 • select m d.s. of DKSol with D2 • back scattered muons == purity CM27 - RAL

  13. we already have an initial solution: the “central value” • Key Point • materials in the BL cause energy loss • (also emi_growth) • in order to have P_mice=200 MeV/c we need to define P_D2 properly • then we define Ppi_tgt • how? • the best choice is dictated by beam purity 3,140 3,200 3,240 6,140 6,200 6,240 10,140 10,200 10,240 CM27 - RAL

  14. In the original scheme the pi  mu beamline is Ppi=444  Pmu=256 Best separation PI/MU p acceptance Will it work? Pdiff = 215 NB.: PD2=256 MeV/c becomes Pdif=215 MeV/c CM27 - RAL

  15. i.o.t. accommodate several mu momenta another “shortcut” scheme was adopted (aug 2009): Define one lower Ppi ~ 350/360 and several different Pmu (we lose in purity …) p acceptance Pdiff = 148 215 256 Ppi (tgt) = 350 195 350 CM27 - RAL

  16. d.s. BL tuning: match to diffuser m Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Dipole1 Dipole2 DK solenoid p fix D2 fix D1 Pp=444 MeV/c Pm=255 MeV/c Pm=214 MeV/c Pm=208 MeV/c CM27 - RAL 16

  17. - a first round of the BL optimised • (e,P) matrix has been produced • in august 2009 (“shortcut”) • however the few data taken in november • reveal a pretty strange look • one thing I dislike is using only one • momentum for the pion (US) component and • Select the backward going muons CM27 - RAL

  18. http://mice.iit.edu/bl/MATRIX/index_mat.html CM27 - RAL

  19. ~29. RUN 1174-1177 – PI- (444MeV/c) MU- (256 MeV/c) at D2 PI- should be here: 30.44 NB: DTmu(256)= DTmu(300) * beta300/beta256 = 28.55 * .943/.923 = 29.13 CM27 - RAL

  20. ? PI- should be here: 30.44 RUN 1201 – PI- (336.8MeV/c) MU- (256 MeV/c) at D2 MU- should be the same as before … what is that? CM27 - RAL

  21. Generate Gaussian Beam with defined COV-MAT (arbitrary statistics) G4Beamline Generation up To DS x’ COV-MAT x y’ CM27 - RAL y

  22. wrap-up … • Consider all 9 cases: one Ppi + one Pmu per case (no “shortcuts”) • Define initial BL currents (from scaling tables) • Check tuning with G4Beamline • use simulation output at DS to infer the COV-MAT of the beam • Generate a Gauss-beam with that CovMat: • E.g. MatLab tool, fast + any number of particles … • Propagate / optimise this beam in the DS section • By hand (GUI tool) • By algorithm (GA) • check results versus real data … CM27 - RAL

  23. CM27 - RAL

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