1 Beamline Session Talk #TimePresenterTalk Title 19:00C. BoothMICE Target Development Status 29:15T.J.RobertsTarget Source Calculations 39:30P.SolerParticle ID Along The Beamline 49:45K.TilleyDesign Concept and New Baseline Description 10:30Coffee 510:45T.J.RobertsBeamline Performance with New Magnet Descriptions. 611:30All/K.TilleyGeneral Discussion MICE Collaboration Meeting CERN Tues am. 30/03/04. Room

MICE Target Status Chris Booth 30 th March 2004

The challenge ISIS beam shrinks from 73 mm to 55 mm radius during acceleration Target must remain outside beam until 2 ms before extraction Then enters 5mm (into halo) Must be out of beam by next injection Beam cycle length 20 ms Target operation “on demand”, 1 to 10 (or 50) Hz

The challenge (continued) Operation in vacuum –No lubricated bearings –No convective cooling Operation in radiation environment Must cause minimal vibration Must be completely reliable and maintenance-free

Basic drive specifications Travel >25 mm Peak acceleration (min.) ~1 mm ms -2 =1000 ms -2 =100 g Rep. rate oOn demand 1 Hz  10 Hz (  50Hz?) o(Machine cycle length 20 ms)

Ideal target motion Infinite acceleration!

Diaphragm spring Target Section NS Current design: Moving magnet Array of coils

Advantages Lower mass – light moving magnet (sintered neodymium-iron-boron) Stationary windings – more power, many cooling options Larger travel possible Disadvantages Multiple coils More sophisticated power supply & commutator required Phase and amplitude control required

Control ideas 2 levels –Rapid hardware position feedback to ensure 1-pulse stability. –Pulse-to-pulse monitoring (software) to provide slow adjustments. Position monitoring requirements For monitoring - Precision 0.2 mm, sampled every 0.1 ms For drive phase control - Precision ~ mm, timing ~ 0.2 ms ?

Position monitoring method? LVDT (Linear Variable Differential Transformer) –Good precision, but not fast enough Optical encoder –Excellent precision, probably not fast enough, not radiation hard Capacitive sensor? –Precision, stability, speed not yet clear! Magnetic sensor? –Is electronics rad hard?

Next steps Continue design studies with EEE –Build prototype magnet/coil system Design/make/acquire diaphragm springs with sufficient travel Develop fast position sensing Interface to power supply/driver Implement 2-stage feedback Test and characterise

Timetable?? First prototypeSummer 04 Develop controlAutumn 04 System testsWinter Cooling, stability testsSpring-Summer 05 Rad-hard componentsSpring-Summer 05 Interfaces with ISISSpring-Summer 05 Implement improvementsSummer 05 Final device construct/testAutumn-Winter 05 InstallWinter-Spring 06

MICE Target Development Proposed activities April – August: Any useful inputs from the Collaboration? Chris Booth & team Alternative Position Sensing Ideas…? As per timeline.

MICE Target Source Calculations Tom Roberts Illinois Institute of Technology March 30, 2004

Model of Target and ISIS Beam ParameterValue Protons in Bunch2.5E13 Bunch Frequency1.5 MHz Good Target & Good RF Duty Factor Beam Radius37.5 mm Target Area2 mm 2 Beam Area4418 mm 2 Beam Density Factor*0.1 Protons/sec on Target1.4E12 * Estimate of: (beam density at target)/(average beam density)

Outline of Computation Select beamline tune, determine an enclosing target acceptance (P min, P max, x’ min, x’ max, y’ min,y’ max ) Use LAHET, MARS, and g4beamline (Geant4) to determine pi+ that enter the target acceptance per proton on target Use g4beamline to generate 20M pi+ into the target acceptance, and determine how may good mu+ they produce. Model the ISIS beam and target to determine the rate of protons on target. Put the above values together to determine the absolute rate of good-mu+/millisecond.

Target Particle Production ParticleLAHETMARSGeant4 pi-3.2E52.8E5 e-4.6E31.5E4 e+01.6E4 gamma7.0E55.6E5 pi+7.8E51.1E69.7E5 n7.2E64.1E6 p3.7E56.2E63.6E6 Particles into acceptance per millisecond of good target.

Target Source/Physics Work Proposed activities April – August: Any inputs requested from Collaboration? Tom Roberts & team Only nominally minor refinements... None suggested.

Particle ID in the MICE Beamline MICE Collaboration Meeting 30 March Paul Soler, Kenny Walaron University of Glasgow and Rutherford Appleton Laboratory

20 Aims Carry out particle identification in the MICE beamline using scintillation detectors. Use dE/dx signature to differentiate between protons and pions/muons at different positions along beamline: e.g. before Q1 and at input and output of solenoid. Use PID information to qualify and monitor beamline simulation. Caveat: More a statement of intentions than results.

21 Scintillator layout o Would aim to have as little segmentation as possible o If rate proves to be a problem, perform segmentation, with smaller segmentation in centre. For example: Scintillator PMTs Waveguides PMTs o Double sided readout allows to measure energy, independent of position of particle along scintillator.

22 GEANT4 Beamline Simulation o MICE beam simulation prepared in GEANT4 (see Tom Roberts presentation 24/9/03 and 14/1/04) showed differences between G4 and other simulations: LocationLAHETgeant4 After Q After Q After Q After Q After Q After Q After Tracker Good μ + (40°) Good μ + (90°) Good μ + (no LH2, no RF) % difference! Need to validate simulations by measuring rates, profiles and particle ID along beamline.

23 MICE Beamline New beamline layout (Tilley/Roberts) Q1 Q2 Q3 B1 Q4 Q5Q6Q7Q8B2 Proton Absorber TOF1 Diffuser2 Decay Solenoid PID scintillators?

24 Conclusions o MICE beam simulation prepared in GEANT4 by Tom Roberts to be used for beam and PID studies o Have started working with it, but still need to learn more about programme and try to run different configurations. o In the process of including particle ID elements to enable design of scintillators (ie. segmentation, thickness) to cope with particle rates.

Particle ID along beamline Proposed activities April – August: Any useful inputs from the Collaboration? Paul Soler, Kenny & team * Experience with g4beamline * Evaluation of JAN04/MAR04, for rates/beamsizes, possible PID positions/segmentation. etc Other detector ideas to handle high rates near target ~ 1GHz?! ie Cherenkov detector??

paul drumm, mutac jan Design Concept & New Baseline Description. Kevin Tilley, ISIS, RAL Brief Review of Design Concept: Beam Matching & Emittance Provision Design Concept New Baseline Description: Pre-amble: Abingdon & JAN04 Inputs for Revising Layout Design of Present Layout & Results. Summary

paul drumm, mutac jan Design Concept ‘Lite’ Scheme to provide simulateously:- This is the driving Design Concept in this design work: To use ‘Beamsize’ & ‘Scatterer thickness’ to provide both beam matching, & required emittance generation. 1. Focus Beam with x/y x’/y’ MICE ACCEPTANCE 2. & Matched after passing thru’ required scatterer [Above figure illustrates case match region immediately follows scatterer]

paul drumm, mutac jan Inputs for Revised Layout Collection of the Major inputs compiled after January ’04: …. Focusing and matching with Q35 Quads affirmed & not coils. Not designing achromatic muon extraction (maybe some residual dispersion…) Extend B1 – Decay Sol distance to fit wall-hole geometry (hole ≈ 650mm) Muon purity as high as possible (C 2 H 4 absorber, pion focus at B2?) TOF0 – TOF1 Q4/Q5, Q8/Q9. Min Sepn 6.9m JAN04. TOF length 15cm. Q9 Saturation: Q9 – Start / End Coil 1.1 distance no closer than JAN04 (Q9 0.08T) → End / Q9MP – St/EC 1.1 ≥ m Minimum Physical Pb. to Start / EC 1.1 distance: EC-VacCh ~ TrServ ~ UpStrDtrSh ~ Space → Take 0.390m. (here it is thus after Cherenkov & before any Upstream Detector Shielding) Max Additional total lengthwise movement of beamline/MICE – 2.00m Initial Muon Momentum Pu = 260Mev/c, for 236.5Mev/c after Pb (aiming at ctr A.v.p for p ref =200) Design for suitability at Spectrometer End Coils NOT available for beam matching. Quadrupole / Dipole FFs neglected. Use magnet effective lengths. Incorporate further changes to become more realistic for MICE:-

paul drumm, mutac jan Muon Extn Design: Difficulties with finite Pb, - End Coil Seperation : Finite distance to matching region (EndCoils here) means incoming beam must be heavily converging into scatterer in order that still converging to matched focus at EC. - First assessment of revising matching conditions before scatterer, based on free field region Pb → EC. start. Clearly approximation, and ‘maybe pessimistic?

paul drumm, mutac jan End Product Design Layout

paul drumm, mutac jan Assessment with TTL NET. after the Scatterer, and Going into the Experiment… +/-1% ~ Higher p ~ 237Mev/c. +/-1% ~ 212Mev/c. WELL MATCHED ~ 212Mev/c PARTIALLY MATCHED? ~ 237Mev/c ~237Mev/c, Δp/p~11.6%:

paul drumm, mutac jan Assessment with TTL … First Estimate of where this might cover on the A.v.p momentum correlation chart?- =237Mev/c 212Mev/c 265Mev/c 209Mev/c

paul drumm, mutac jan Summary Design Concept described. Motivations behind present baseline layout given. New ‘Baseline’ described. Current beamline provides ~237Mev/c, Δp/p~11.6%: Well matched component at Partially matched dominating higher momentum component. Intention to revise for well 236.5Mev/c. Current modelling forced Pb-EC → 0 based on scheme. Clearly one priority to consider same finite d cases including MICE (EC/SS) FFs Incorporates most of other inputs.

Design Concept & New Baseline Description Any inputs need discussed by Collaboration? Kevin Tilley 1. Can we live with the present Good-beam ≠ p-peak ? → whatever accomodation: p – specified - lowered (→ benefit from MAR04 Evaln of 212 for current #s. (Could also study benefit simplistically Good-beam = p-peak, as only chg!). 2. Affirm (how?) aiming ‘directly’ for Correlation? Never ‘quite’ understood > ≠p-ref (mgt currents)

Design Concept & New Baseline Description Proposed activities April – August: Kevin Tilley 1a. Accelerator physics issues for Good-beam = p-peak, if sanctioned. “SHOW-STOPPER SCENARIO” - present known alleviating factors: RIKEN dec ch.-like ? B2-angle. 1b. Study acceptable beamline changes affect on wall-hole position, if sanctioned. “PROBLEM-’LITE’ SCENARIO”. (Ideally preferred if own constraints werent prob) 1c. Study potential future beamline changes to accommodate. “PROBLEM-LIVEWITH SCENARIO”. 2.Reach agreement/incorp explicit fringe fields in bends/quads → minor revision? (see also CodeConvergences) 2/3a.Investigate accurately affect of MICE FF on match & update min. Pb dists to end coils for 6π (+). 2/3b.Investigate actual Pb thickness for 200ref-p, 236.5Mev/c (Avp) match. (3a&3b) → Nominal Pb. position / weight support rqst for ReEn VacCh specs. 4. Exploring limits of available design 4 MICE (difft ref-Momentum, achievable emittances (Pb-l), rates etc)? Achievable patch on A.v.p correlation?. Code Convergences? (even whilst g4beamline evaln soon exceed potential realism TTL, also even with statement g4beamline view as future final optimiser) – Э 2x+ support for continuing comparing ‘now’+. “In parallel” tho since accepted eg. not priority in view of answering immediate engineering q’s (eg. wall hole, Pb? ….) Schedule plans with collaborators (TJR, PS etc, as necessary).

MICE Beamline Performance with New Magnet Descriptions Tom Roberts Illinois Institute of Technology March 30, 2004

Progression of Magnet Descriptions JAN04 was designed using block fields, except for the DecaySolenoid which used the coil field (no iron) In the New York Meeting I applied a simple Laplace solution for the fringe fields of B1 and B2; since then I have implemented COSY-style fringe fields for bends and quads Full “rounded +” apertures in the muon quads Q4-Q9 (Q1-Q3 have circular apertures) Good magnetic map of the DecaySolenoid, including its iron Good magnetic map of the upstream and downstream magnetic shields

Comparison of Laplace to COSY-style fringe fields All computations have the same integral By dz.

Downstream Magnetic Shield (r and z scales are different)

Effects of the Improved Descriptions DescriptionFactorCumulative JAN04 (block fields)1.00 Full apertures in the muon quads Q4-Q COSY-style fringe fields in Bends and Quads Iron in DecaySolenoid Magnetic shielding upstream and downstream Factor is from the good-mu+ rate.

Results Normalization Program Good mu+ per ms LAHET304 MARS419 g4beamline375 Major Variables: Beamline tune can vary rates by a factor of ~6 (tuning for lower input emittance yields higher good mu+/proton) Target dip height directly affects protons on target (must keep ISIS losses within bounds) JAN04 tune, 6π mm-rad input emittance, no LH2, no RF. Because of the large variations in yield for different tunes, and the need to keep ISIS losses to a minimum, an easily- adjustable insertion depth for the target is essential.

Beamline Performance/New Mgt Descriptions Any inputs need discussed by Collaboration? Tom Roberts 1. Required beam rate? 600 Gd /sec? Know: – st. retune/cte studying/…invoke Tgt depths etc. if less. Know Why: – st. to know context ie. apply to all Emittances/extnl constraints? MINIMUM? (maximum?) 2. Acceptable purities? Can go worse? Worst eg. ~ TOF0, TOF1 etc?.

Beamline Performance/New Mgt Descriptions Proposed activities April – August: Tom Roberts 1.Evaluate new layout MAR04 / Reach agreement for explicit fringe fields in bends/quads.(see also CodeConvergences) 3. Appropriate integration with g4mice? Layouts, detectors? (detectors: – TOF 2 utility?.) Coding folding in issues also?? boundary point / Code Convergences? (even whilst g4beamline evaln soon exceed potential realism TTL, also even with statement g4beamline view as future final optimiser) – Э 2x+ support for continuing comparing ‘now’+. “In parallel” tho since accepted eg. not priority in view of answering immediate engineering q’s (eg. wall hole, Pb? ….) Schedule plans with collaborators (KT, PS etc, as necessary)

Beamline Technical Baseline Tech Reference is not complete: –Review what is presented; –Identify what is missing and who is charged to prepare it; But only by KT after Session  Suggestions by KT below…. 1.4 Beam line Layout - Some minor mods – KT responsibility for 1.5 Expected Performance – To be updated with MAR04 – TJR agreed to provide. “MISSING/AWOL”: Re-insert as 1.6? Diagnostics? – Paul Soler/ PD ?

Beamline Technical Baseline Tech Reference is not complete: –Identify what is agreed (or not) as the baseline Following aforementioned suggested mods to TRD → BECOMES DESCRIPTION OF CURRENT BASELINE ??.