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Beamline Session. MICE Collaboration Meeting CERN Tues am. 30/03/04. Room 6-02-24. 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

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Beamline Session


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beamline session
Beamline Session

MICE Collaboration Meeting CERNTues am. 30/03/04. Room 6-02-24.

mice target status

MICE TargetStatus

Chris Booth

30th March 2004

the challenge
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
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
Basic drive specifications
  • Travel >25 mm
  • Peak acceleration (min.) ~1 mm ms-2 =1000 ms-2 =100 g
  • Rep. rate
    • On demand 1 Hz  10 Hz ( 50Hz?)
    • (Machine cycle length 20 ms)
slide6

Ideal target motion

  • Infinite acceleration!
slide7

Diaphragm spring

N

S

Array of coils

Current design:

Moving magnet

Section

Target

advantages
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
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
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
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
Timetable??
  • First prototype Summer 04
  • Develop control Autumn 04
  • System tests Winter 04-05
  • Cooling, stability tests Spring-Summer 05
  • Rad-hard components Spring-Summer 05
  • Interfaces with ISIS Spring-Summer 05
  • Implement improvements Summer 05
  • Final device construct/test Autumn-Winter 05
  • Install Winter-Spring 06
mice target development
MICE Target Development

Chris Booth & team

  • Proposed activities April – August:
  • Any useful inputs from the Collaboration?

As per timeline.

Alternative Position Sensing Ideas…?

mice target source calculations

MICE Target Source Calculations

Tom Roberts

Illinois Institute of Technology

March 30, 2004

model of target and isis beam
Model of Target and ISIS Beam

* Estimate of: (beam density at target)/(average beam density)

outline of computation
Outline of Computation
  • Select beamline tune, determine an enclosing target acceptance (Pmin, Pmax, 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
Target Particle Production

Particles into acceptance per millisecond of good target.

target source physics work
Target Source/Physics Work

Tom Roberts & team

  • Proposed activities April – August:
  • Any inputs requested from Collaboration?

Only nominally minor refinements...

None suggested.

particle id in the mice beamline

Particle ID in the MICE Beamline

Paul Soler, Kenny Walaron

University of Glasgow and

Rutherford Appleton Laboratory

MICE Collaboration Meeting

30 March 2004.

slide20
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.
scintillator layout
Scintillator layout
  • Would aim to have as little segmentation as possible
  • If rate proves to be a problem, perform segmentation, with smaller segmentation in centre. For example:

Scintillator

Waveguides

Waveguides

PMTs

PMTs

  • Double sided readout allows to measure energy, independent of position of particle along scintillator.
geant4 beamline simulation
GEANT4 Beamline Simulation
  • MICE beam simulation prepared in GEANT4 (see Tom Roberts presentation 24/9/03 and 14/1/04) showed differences between G4 and other simulations:

57% difference!

Need to validate simulations by measuring rates, profiles and particle ID along beamline.

mice beamline
MICE Beamline

New beamline layout (Tilley/Roberts)

PID scintillators?

Q1

Q2

Q3

TOF1

TOF1

Diffuser2

B1

Decay

Solenoid

Proton

Absorber

B2

Q4

Q4

Q5

Q6

Q7

Q8

conclusions
Conclusions
  • MICE beam simulation prepared in GEANT4 by Tom Roberts to be used for beam and PID studies
  • Have started working with it, but still need to learn more about programme and try to run different configurations.
  • 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
Particle ID along beamline

Paul Soler, Kenny & team

  • Proposed activities April – August:
  • Any useful inputs from the Collaboration?

* 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??

design concept new baseline description

Design Concept & New Baseline Description.

  • 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

Kevin Tilley , ISIS , RAL

design concept lite
Design Concept ‘Lite’

x’/y’

1. Focus Beam with

x/y

2. &

Matched after passing thru’ required scatterer

MICE ACCEPTANCE

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.

[Above figure illustrates case match region immediately follows scatterer]

slide28

Inputs for Revised Layout

Collection of the Major inputs compiled after January ’04: ….

  • Incorporate further changes to become more realistic for MICE:-
  • 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 (C2H4 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 ≥ 1.2169m
  • Minimum Physical Pb. to Start / EC 1.1 distance:
  • EC-VacCh ~ 0.195 + TrServ ~ 0.03 + UpStrDtrSh ~ 0.15 + 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 pref=200)
  • Design for suitability at
  • Spectrometer End Coils NOT available for beam matching.
  • Quadrupole / Dipole FFs neglected. Use magnet effective lengths.
muon extn design
Muon Extn Design:

Difficulties with finite Pb, - End Coil Seperation :

- First assessment of revising matching conditions before scatterer, based on free field region Pb → EC. start. Clearly approximation, and ‘maybe pessimistic?

  • 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.
slide31

Assessment with TTL

NET. after the Scatterer, and Going into the Experiment…

WELL MATCHED BEAM @ ~ 212Mev/c

+/-1% ~ 212Mev/c.

+/-1% ~ Higher p ~ 237Mev/c.

PARTIALLY MATCHED? CMPT @ ~ 237Mev/c

<p>~237Mev/c, Δp/p~11.6%:

slide32

Assessment with TTL

… First Estimate of where this might cover on the A.v.p momentum correlation chart?-

265Mev/c

<p> =237Mev/c

212Mev/c

209Mev/c

summary
Summary
  • Design Concept described.
  • Motivations behind present baseline layout given.
  • New ‘Baseline’ described.
  • Current beamline provides <p>~237Mev/c, Δp/p~11.6%:
      • Well matched component at 212Mev/c @
      • Partially matched dominating higher momentum component.
      • Intention to revise for well matched @ 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 description1
Design Concept & New Baseline Description

Kevin Tilley

  • Any inputs need discussed by Collaboration?
  • 1. Can we live with the present Good-beam ≠ p-peak ?
  • → whatever accomodation: N(Good(μ) @ p – specified - lowered
  • (→ benefit from MAR04 Evaln of N(Good) @ 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> > ≠p-ref (mgt currents)
design concept new baseline description2
Design Concept & New Baseline Description

Kevin Tilley

Proposed activities April – August:

  • 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

MICE Beamline Performance with New Magnet Descriptions

Tom Roberts

Illinois Institute of Technology

March 30, 2004

progression of magnet descriptions
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
Comparison of Laplace to COSY-style fringe fields

All computations have the same integral By dz.

downstream magnetic shield
Downstream Magnetic Shield

(r and z scales are different)

effects of the improved descriptions
Effects of the Improved Descriptions

Factor is from the good-mu+ rate.

results
Results

JAN04 tune, 6π mm-rad input emittance, no LH2, no RF.

  • 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)

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
Beamline Performance/New Mgt Descriptions

Tom Roberts

  • Any inputs need discussed by Collaboration?
  • 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. ~ Mu/Pion @ TOF0, TOF1 etc?.
beamline performance new mgt descriptions1
Beamline Performance/New Mgt Descriptions

Tom Roberts

Proposed activities April – August:

  • Evaluate new layout MAR04 / 5.3.
  • 2. 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
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 baseline1
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 ??.