mice beamline: plans for initial commissioning
DESCRIPTION
MICE Beamline: Plans for initial commissioning. Target, detectors, particle production Upstream beamline Downstream beamline: Step 1 Jan 20 - March , Step 2 April – June. Summary. Kevin Tilley, 16 th November. - 75days until commissioning. (& 9hours). Charge. - PowerPoint PPT PresentationTRANSCRIPT
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MICE Beamline: Plans for initial commissioning.
Kevin Tilley, 16th November. - 75days until commissioning
• Target, detectors, particle production
• Upstream beamline
• Downstream beamline:
•Step 1 Jan 20 - March , Step 2 April – June.
• Summary
(& 9hours)
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Charge.
Meaning in commissioning….
Optics goals: Step1 (Jan-March): Verify can achieve approximately right beamsizes & waists at MICE. Ensure reasonable transmission & flux. Measure alignment.
Optics goals: Step 2 (April–June): Match beam with diffuser. Find & demonstrate (ε,p) beam cases. Demonstrate purity.
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Beamline layout & diagnostic devices
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First things first – target, detectors, particle production
• Target• Has the target got the required acceleration?• Insert target shallow dip depth, measure reproducibility/flux/loss reproducibility • Insert target into towards 38mm if ISIS beam loss ok, or else acceptable loss.
• MICE & Beamline Detectors• Target in, only dipoles on, P(B1=B2)=350MeV/c. Negative polarity (pi-)
Calibrate detectors
• Particle production• with only dipoles on, P(B1=B2), characterise pion flux versus momentum • relatively simple with MICE PIDs.• ….useful for extrapolating to expected rates.
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Step1:- Beamline optics commissioning
Optics goals: Step1 (Jan-March):
Verify can achieve approximately right beamsizes & waists at MICE. Ensure reasonable transmission & flux. Measure alignment.
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Step1:- Upstream beamline optics
• Upstream goal:-
• Maximum pion flux at detector D1, on axis & aligned pion beam. (=max muon flux, on axis & aligned muon beam. Slightly open question = to confirm this equivalence?) Minimum pion spot size to aid collimation.
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Step1:- Upstream beamline optics
• Basic optics checks … … (1/2)
• Set P(B1=B2) = design setting 444.7MeV/c.
• Check basic optics of Q1-Q3. (compare to model)
– Individual quads fields scanned:-- measure beamsize changes at U1,D1 - fit to Q1 effective length?- measure beam centroid changes at U1,D1
- fit to any residual target misalignment
- Alternatively fields fixed, Target dip change.- - measure beam centroid changes at U1,D1
- refit to any residual target misalignment
• Open question:- can beamsize changes & centre changes be seen U1/D1 (strong vert focussing B1, distance to D1)
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Step1:- Upstream beamline optics
• Basic optics checks………. (2/2)
• Set Q1,Q2,Q3, Decay solenoid design optic.
• Set P(B1=B2)
• Check basic optics of Decay Solenoid:-
– Ramp field (beam phase advance), measure beamsize at D1
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Step1:- Upstream beamline optics
• Optimise:-
• Set all fields to design settings. P(B2=B1)
• Optimisation methods:-1. Scale (Q1,Q2,Q3) as a single unit, & decay
solenoid as a single unit.
example:-scaling Q1-Q3 single unit:-
2. Decouple & optimise eg Q1. Optimise 3 parameters:-((Q1,(Q2,Q3),Decay solenoid)
3. Further free up parameters & optimise.
Q1'
Q2'
Q3'
IWin
AIR
BWin
USDW
Q1'
Q2'
Q3'
IWin
AIR
BWin
USDW
Goal:- Maximum pion flux at detector D1, on axis & aligned pion beam. Minimum pion spot size to aid collimation.
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Step1:- Downstream beamline optics
• Downstream Goal:-
• (Goal of Step1) Verify can achieve approximately right beamsizes & waists at MICE. Ensure reasonable transmission & flux. Measure alignment.
• Suggest aim at just one case initially ~(6pi,200MeV/c)
Open question: is setting up the downstream beamline with pions of benefit to us? Advantages, but in extreme: are optics for pions suitable for muons? (simulation question)Default is currently to setup beamline with muons until understood.
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Step 1:- Downstream beamline optics
• Basic optics checks:- (1/1)
• B2 scan – backward/forward muon momentum edges.
• Basic quadrupole optics – quads in triplets
• Open question: has TOF0, TOF1 or Tracker sufficient resolution – with sensible rates?
• Use beam monitor as a fallback if not.
• Beam misalignment check, by scanning quads fields (near reasonable focus)
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Step 1:- Downstream beamline optics
• Measurements:-
• Set downstream beamline to have design optics.
• Confirm beamsizes at MICE approximately correct.
• Measure misalignment at Tracker
• Measure transmission efficiency D1- Tracker.
• Measure natural emittance of beamline :• (for feeding back to calculate required alpha/beta).• Use 3 tracker planes & TOF assuming muons form 97%,
to make offline momentum cuts.
• Recalculate desired beamsizes/waists.
• Attempt to obtain desired beamsizes/waist… (PTO)
Goal: Verify can achieve approximately right beamsizes & waists at MICE. Ensure reasonable transmission & flux. Measure alignment
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Step1:- Downstream beamline optics
• Optimise :- (Attempting to obtain desired beamsizes/waist)
• Optimisation techniques for optimising beamsize/waist in Tracker:-
• (some are open questions to answer efficacy)
• By hand single lens scaling of (Q456) / (Q789), then decouple in stages.
• TRANSPORT envelope fitting: measure beam at Tracker, use known Q789 settings,TOF0 beamsize -> determine input beam at TOF0 ->solve for Q789 for 3-rqd parameters at MICE.
• Construct empirical response matrix (in quantites to be determined) and solve for Q4-Q6.
• Optimiser.
Goal: Verify can achieve approximately right beamsizes & waists at MICE. Ensure reasonable transmission & flux. Measure alignment
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Step2 – Downstream optics
• Similar optimisation techniques to previous slide..
Optics goals: Step 2 (April–June): Match beam with diffuser. Find & demonstrate (ε,p) beam cases. Demonstrate purity.
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Summary
• Goals for Step 1 commissioning: proposed
– Do upstream optics separately. Sub-goal proposed.• Basic optics• Optimisation
– Do downstream separately. Sub-goal proposed.• Basic optics • Optimisation
• Goals for Step 2: proposed Goal:- Match beam with diffuser.
Find & demonstrate (ε,p) beam cases. Demonstrate purity.
• Optimisation of downstream section uses similar techniques to Step1.
Goal: Verify can achieve approximately right beamsizes & waists at MICE. Ensure reasonable transmission & flux. Measure alignment