1 1 Optics related work: the major threads: -Current (ε,p) status - G4BL/TTL Simulation comparisons - Beam steering/correction -Collimation d/stream & upstream. Beamline diagnostics Plan Conclusions Status of Beamline Optics MICE CM18 14 June 2007

2 2 Current (ε,p) Beamline Cases Current optics (mainly as per CM16) :- MeV/c TT: Transport & Turtle G4: G4Beamline (incl new Ckv1) pp 11 66 10  TT G4BL TT G4BL TT G4BL (May’07) 140 … with the same apparent "+'s" and -'s as before ie: G4BL-ε ~ 2xTTL-ε. G4BL optical match uncertain

3 3 Current (ε,p) Beamline Cases TTL beam from CM through MICE lattice shown to cool in ICOOL (MA) – see Marco’s draft of further cooling studies (see minutes of beamline optics mtg on 20/2/07)cooling studies TTL designed beam ok in MICE.

4 4 Significant differences G4BL & TTL codes: - G4BL emittances are ~2x TTL emittances – due to beamsize < diffuser - Match in MICE also different – same reason. Need to understand and fix the source of any differences (both codes have advantages - how do we know which – if either – is right?) G4BL/TTL Simulation Comparison

5 5 Downstream lattice (Pre-CM17 state)

6 6 Downstream lattice:Possible causes & sequence to understand Pre-CM17 case CM18 G4BL/TTL Simulation Comparison Air & m/s in TTL. No FF in G4BL

7 7 Current results of detailed study: G4BL/TTL Simulation Comparison Just block magnets (no scattering, etc) Small 0.3pi mm rad beam from after B2. Agreement ! Just block magnets. Larger ~ 1pi mm rad beam. Disagreement! Possible causes:- Quad edge aperture fields TTL/G4BL.? Paraxial approximation in TTL? Quads

8 8 Current results of detailed study: G4BL/TTL Simulation Comparison Just block magnets. Larger ~ 1pi mm rad beam. Disagreement at exit of B2. No vertical focussing in B2 (G4BL). Dipole B2

9 9 Current results of detailed study: G4BL/TTL Simulation Comparison Small ~ 0.3pi mm rad beam. Colours represent different combinations of fringe fields enabled – see “Small-beam effect of g4bl fringe field plots” – see beamline optics minutes 7 June 2007plots Seems overly large effect in vertical vs horizontal. Still to compare to TTL G4BL Magnet fringe field study (Still to compare to TTL) Code comparison studies ongoing but already a number of differences that we are close to understanding. Can we fix? (We do have good field maps for all the downstream magnets available to use in tests/simulation) x y

10 Beam Steering/Correction Scheme Current baseline is still as per CM14/Osaka. (Further study should follow from trustworthy beamline model) Current scheme is: B2 VSM1 CKV1 VSM2 HSM1 Q4-6 Q7-9 TOF0 TOF1 (some) issues:- - recheck with realistic magnet misalignments. - use of 3 SMgts + B2 to perform correction (B2 used for p0 selection) so quantitatively, what is the effect on end? hysterisis effects in B2? - possible inclusion of HSM2 > Q9. - Apertures & Space provision: VSM1 / Collimator - will biased quadrupoles suffice? ISIS TS2 steering magnet

11 Beamline Diagnostics Studied intensely in beamline group since CM17. Much material in May10 VC Upstream monitor: –Main location –Applications : relative flux, beamsize, beam position, later BBA? –192x192mm, up to GHz inst rates, monitor magnetic fields. –Readout (ADCs) & EPICS Downstream monitor:- –Main location & other locations –Applications: flux, beamsize, beam position, later BBA? –432x432mm, GHz down to ~ 2MHz, monitor magnetic fields. –Readout (disciminators + scalars) Hope for both in ~ mid August

12 “Plan” Not so easy nor likely on ~ 1FTE !

13 Progress is not fast - ~ (1.0 FTE ) but some new faces providing v useful help, Focussing on priorities: Progress on understanding (6pi,200) G4BL/TTL discrepancy Beamline detectors specified & BL commissioning issues being addressed Steering scheme: some issues still to address Collimation schemes: various issues to address Beamline Commissioning being given increased consideration…… Conclusions