1MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

Answers to the International Peer Review Panel

1. Can be found at http://proj-bdl-nice.web.cern.ch/proj-bdl-nice/cool/proposal/answers-iprc/answers_ral.pdf

2. were assmbled thanks to contributions from many, in particularK.Long and Sci-Fi team

U. Gastaldi and TPG teamF. Sauli

G. GregoireY. Torun and software team

P. Janot/A.B.B. Palmer

R. EdgecockP. Drumm

M. Zisman and RF team M. Zisman and the AFCSTF

about 30 pages (5 of questions and 25 of answers)

2MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

Dear Alain

I am extremely grateful for the efforts which you and your colleagues must

have put into getting your answers to us in writing in good time for our

meeting on 2 May. It will help to focus our discussion.I understand that

we may get further comments from your collaborators.

Regards and have a restful Easter!

Alan Astbury

3MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

1 Experimental detector issues1.1 Sci-Fi tracker. good news: simulation of multiplexed tracker shows resolution degraded only by a factor of about 2. (shows that MS in tracker is large efect for non-mpx’d system)remains to include: RF-induced noise + nice strategy for alignment

1.2 TPG tracker 1.2.1 It is important to test a full drift length using the triple GEM technique …gave schedule of test for TPG this summer and milestone of ‘Tracino’1.2.2 Is the uniformity of "better than 1%", assumed for the 1000 mm by 300 mm diameter solenoid good enough for the imaging performance of the TPG? Here is a difficulty main problem is not just the B-field but the parallelism of B and EB will be measured but not E! need a calibration/alignment strategy A complete calibration system for a TPG for MICE has not been fully designed, and a definite answer to this question is not possible at this point. This issue will clearly be addressed in the internal review leading to a choice for the tracker.

4MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

1.2.3 Has an estimate been made of the effect of RF noise and x-rays on the GEMs?

Sauli made a calculation of the probability for a photon to create a photo-electron on the GEM itself which then leads to a cascade and noise. Seems about equal to probability in Helium. Must be verified bytest with x-rays. (preferably at Lab G)

5MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

1.3 Timescales for the tracker

described the procedure for choice, the names of internal referrees (Grégoire and Summers) and the goals to be achieved.

1.4 Safety factor What is the loss performance in the spectrometers which will compromise the measurement? How large is the safety factor?

recalled the requirement in the LOI (1/10 of the beam size at equilibrium emittance)beam size in transverse momentum is about 10 MeV at eq. emittance we have 110 keV Pt resolution with sci-fi 270keV multiplexed.35 keV for TPG

6MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

 1.5 Particle IDconcerns are the homogeneity of response over the required surface area, and how this can be proved, and the risk of bias (in terms of phase space population) through loss of muons by unwanted rejection in the particle ID systems (e.g. position, incident angle, and energy dependence of "over-vetoing" of electrons in the calorimeter or Cherenkov).

problem surfaced!

In fact the full downstream PID was designed for 200 MeV muons (not 200 MeV/c!) as a consequence the design should be revisited……

Apart from this unpleasant discovery, which was not mentioned, the redundancy of the system should allow mapping of efficiency over the phase space. Examples were given.

7MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

2. General experimental questions  2.1 Is there a plausible general argument to support the claim that the correlation of the measurement of the emittance of the incoming and outgoing muons improves the statistical precision of the difference measurement?

gave ref. to Janot. Transverse momentum gained in absorbers (5 MeV/c) is smaller than intrinsic transverse momentum of the beam (10 MeV/c or more)

8MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

2.2 There is a statement, "it is believed that the systematic errors on the ratio of the output to input emittance can be kept at the level of ± 10-3 or better", is this merely a pious hope, or is there evidence to justify it?

This was not too difficult. We need to control energy loss, MS, and energy gains with required precision. 1. just two spectrometers -> measure ratio of emittance to << 10-32. empty MICE and no RF should provide the same 3. fill absorbers, no RF measure dE/dx and MS in LH24. RF ‘ON’ measure energy gain as a function of RF phase5. RF ‘ON’ vs RF ‘OFF’ measure effect of x-rays on trackers

in addition:measure magnetic functions (magnetic measurements)measure RF volts (electric loop?) measure effective mass of LH2 in the way of muons (not so trivial)i) measurement of the absorber thickness before installation, but with a filling of hydrogen,ii) measurement of the hydrogen pressure, iii) measurement of the hydrogen temperature.

9MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

- STEP I: 2004

STEP II: summer 2005

STEP III: winter 2006

STEP IV: spring 2006

STEP V: fall 2006

STEP VI: 2007

If funding is adequate, the following sequence of events can be envisaged:

10MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

2.3 The re-weighing of the particle density is used as an argument to allow the experiment to make many studies with one data taking setting. However this comes at a price in terms of statistics. What would be the real statistics needed to reach the required effective statistics for the worst case? example 1:

reweighting to achieve this would require factor 50 loss in particles. (run 50hrs instead of one)

11MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

Another case was emphasized by Bob:

what is the loss in statistics that corresponds to reqeighting a flat beamto a beam with such amplitude-momentum correlation?

answer is: being calculated.

12MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

2.4 Is it possible to provide a plan of the envisaged experimental program, indicating which configurations will be explored, and what kind of changeover times are anticipated? This question has a bearing on the different magnetic forces which will be experienced. It also impacts the question of how essential the decay solenoid is for the beam line.

Rob delineated a rather complete description of the programme.Solenoid is really more than welcome.

issue: The useful fraction was estimated to be 4% at the time of the proposal, assuming an input pencil muon beam. More recent simulations using the real muon beam parameters have estimated this fraction to be smaller, approximately 0.1%. However, these simulations are continuing and are indicating that the addition of optical elements (quadrupoles or coils) along the beamline or in the 10m between the two diffusers could improve this number by a large factor, 50 or more. We are also investigating the real limits on the target thickness in the running conditions of MICE. As this work is not yet complete, the value of 0.1% is used for the programme below and this should be considered the minimum that MICE can achieve

13MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

2.5 This question concerns the MICE proponents with input from expert committee members. Because of costs, etc., might it not be necessary to quantify the gains which may follow from exploring set-up VI, beyond set-up V, in figure 3.13. Is this step a luxury or prudent insurance against a situation where cooling is less then expected?

 Answer: 1. this is one full cell of the cooling channel.2. this configuration allows many different configurations to be tested3. better use of the RF power vs cooling performance, at a reduced RF

voltage reduced x-ray background.4. the incremental cost is 2.03 M $. 5. this is less than the incremental cost of a full-fledged tracker

Although the configuration of step V would be better than nothing, we believe that the full MICE configuration proposed is a much better choice.

14MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

2.6 Successful software simulation of the MICE results appears to be an important ingredient for extending the measurement to future cooling configurations. What steps are being taken within the MICE collaboration to set-up the appropriate software team? gave names of coordinators, activities of software team and achievements so far.

15MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

3. RF systems This is perhaps the most challenging accelerator system in MICE, and the proposed 201 MHz cavity structure includes several new and novel aspects, which will need intense R and D effort before moving to construction. The introduction of cavity windows and the operation in a magnetic field are untried innovations. Several questions arise:- * e-beam welds or braze joints* best method to clean and bake cavities•lifetimes of windows(. Ultimately, tests of the prototype 201 MHz cavity will be needed to fully assess this matter. These tests are foreseen when the prototype cavity is available, about 18 months from now.)

* use of copper or copperclad steel * microphonic issues will be an important aspect of cavity timing-the cavity frequency bandwidth corresponds to a 30 µm window displacement* cavity conditioning and multipactoring in the magnetic field-is there a gain from TiN coating* effects at field reversal point Is it possible to indicate a timescale and funding required to cover this R and D? Can it happen within the MUCOOL R & D program of MUTAC at FNAL? Have the proponents considered a small advisory group of recognized RF experts?

16MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

Proposed Muon Cavity Prototype Design and Fabrication Schedule

FY 03 FY 04Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr

Cavity BodyFinalize cavity shell dimensions and drawingsIdentify half-shell fabrication vendorComplete stress/stiffness analysis based on final cavity designProcure material for cavity half-shell fabricationComplete nose design and drawings including clamping schemeFabricate the 2 half-shells including inside machiningDetermine port sizes and locations - complete relevant drawingsFabricate the 2 cavity nose rings and tuner interface ringsE-beam welding of the half-shellsDevelop cavity cooling scheme and layout drawingsDesign RF loop coupler and generate drawingsInitial cavity frequency measurements and adjustmentsE-beam welding of the cavity nose and tuner interface ringsComplete cavity port machining operationsFabricate cavity port connectionsE-beam welding of ports to cavity bodyFabrication of RF loop couplersSoft solder cooling tubes to cavity bodyChemical cleaning of finished cavityElectro-polishing of cavity interiorLow-temperature cavity bakeout

Cavity WindowsComplete curved Be window conceptual design and analysisDesign and test fixturing for 201 MHz curved windowDesign an equivalent 805 MHz curved windowProcure material and fabricate 805 MHz curved Be window(s)Perform initial testing on 805 MHz window using heat lampsTest window on 805 MHz cavityComplete final design and drawings for 201 MHz curved windowProcure Be foil material and fabricate fixturingFabricate 201 MHz curved Be windowsPerform initial testing on 201 MHz window using heat lamps

Tuner and Support SystemDevelop initial tuner concept based on J-Lab tunerDevelop detailed tuner and support conceptual designComplete tuning system detailed design including drawingsProcure and fabricate tuner and support componentsPerform initial assembly and check-out of tuner components

AssemblyCavity assembly including windows and RF couplersInstallation of tuner and support mechanismsInstallation of vacuum systemInstallation of cooling systemFinal leak checking and system check-out

Task Description

17MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

 

4. Liquid hydrogen absorbers   4.1 The R and D on this system is widely dispersed. What are the plans forassembling and testing the completed system, liquid hydrogen container, vacuum, and focusing coils? Where will it occur? Who supplies the infrastructure and safety needs? While liquid hydrogen is the baseline absorber in MICE, to what extent can other absorbers be explored?

Answer anticipated by creation of AFCSWG (M.Zisman et al)

and YES other absorbers will be explored!

18MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

Outline designs

Preliminary Assessments

Proposal for final choice

Detailed design

Manufacture and installation

Permission to operate

RAL Defined Review

Failure ModesStress CalculationsInterlocks &Operational ProceduresContingency PlansPressure Vessel &ATEX regulations….

Hazard and Operability Assessment

Working Group

SequenceDocuments Required

MICE Hydrogen Safety Review Procedure

OK for detailed design

OK to Manufacture

Preliminary Hazard and Operability Assessments

ISIS Safety Officer

Reviews

Panel Review

+

+

Working Group

Technical Groups

19MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

5. Beam line The committee heard that the proposed work plan for the ISIS division in the long shutdown projected to commence in Spring 2004, already stretches resources to the limit. This would appear to make the installation of the new MICE beamline practically impossible without increased effort. The committee would like to hear whether simply enlarging the hole in the shielding wall in the next long shutdown is a possible way forward for MICE. When would the beamline be subsequently completed? Would this step preclude the use of the PSI solenoid? What delay might be envisaged for the MICE program? How would this step impact the required funding and resource profile for MICE? The committee understands that this is not the preferred schedule of MICE, but it may prove to be a realistic one. What is the timescale for a decision on the possible use of the PSI solenoid?

The delay to MICE is likely to be 6 months to one year.Summary:•PSI solenoid decision in early 2004, likely to be at RAL in first half of 2005.•Full beam line ready second quarter of 2006: this depends on the timing of the next long shutdown which is likely to be driven by MICE and the neutron community.ReResource profile will always be peaked during a shutdown: requires MICE to be the dominant activity in the shutdown/shutdown length to

accommodate MICE

20MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

6 Funding The committee realizes that the cost estimates as presented are "physicists'" estimates. This is always a necessary first step. However these estimates must be firmed up with adequate documentation, before funding agencies will give serious attention to a funding request. What steps are envisaged to move forward? Is there a clear view of what amounts are expected from the various agencies involved? Some funds seem to be assumed from MUCOOL R&D, will this continue? What funds, if any, does MICE have already, a piece of MUTAC? It would seem sensible to consider two funding scenarios. One profile which is front loaded to make maximum use of the 2004 shutdown-the preferred profile. A second which makes minimum use of the 2004 shutdown.6 ANSWER What steps are envisaged to move forward? The cost estimates presented in the proposal have been evaluated by the proponents of each subsystem for which they are considered responsible and correspond to the amount that they need to request in order to fulfil their commitment. see table 6 for detailed breakdown (summs up to proposal)

21MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

7. Timescales The committee understands that the preferred MICE timescale as outlined in figure 3.13 is driven by the feeling that a result is needed by 2007. If minimal use is made of the 2004 shutdown how would the dates be modified?   The committee would like to see some milestones which would allow the steps of figure 3.13 to be realized as presented in the proposal, or possibly a modified set of steps from figure 3.13. The most obvious milestones are, * date of beamline completion for step I.* date of decision on trackers for steps II and III.* length of time remaining for R and D on the liquid hydrogen absorbers in order to go into production, achieve a sub-system test, and be ready for step IV.* length of time remaining for RF R and D to produce cavities in time for steps V and VI. * start dates for coil production focusing, coupling, matching, spectrometer, to mesh into the above steps.

22MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

   Milestone Start date

123456

Characterization of muon beamCommissioning of first spectrometerCommissioning of both spectrometersMeasurements with one absorberMeasurements with two absorbers and one RF cavityMeasurements with the full version of MICE

Q2 2006Q3 2006Q1 2007Q2 2007Q4 2007Q1 2008

Table 7:1 Revised milestones that result from a preliminary analysis of the consequences of performing a minimum of work in the next ISIS long shutdown that is scheduled for spring 2004.

23MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

8. Management issues The Rutherford Laboratory is proposing to host MICE. This role will bring significant international visibility to RAL, but it will also demand considerable responsibilities if the project is to proceed successfully. The following observations are made. There is a need for an overall, fairly senior, Project Leader. The RAL team should contain sufficient expertise in sub-systems (RF, magnets, absorbers, etc.) to play a leading role in helping to define them, so that there are no surprises in the "in kind" equipment which arrives at the laboratory for installation. In addition the laboratory will need to supply appropriate engineering coordination to provide the beamline, the infrastructure for the installation of subsystems and spectrometers, plusdefine, implement and manage safety systems. There will also be a need for an experienced UK physicist to assist in the liaison with the physics groups providing the detector components.  The funding for MICE will include international contributions. It would seem prudent to envisage some form of "agency committee" which monitors the funding during the provision of the MICE equipment. There has been no mention of MICE operating funds-a common fund? RAL?  The committee feels that it is not too early for the laboratory to begin to formulate and present a management plan for hosting MICE at RAL.

24MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

25MICE – responses to IPRC – Alain Blondel, MICE V.C. April 23 2003

The funding for MICE will include international contributions. It would seem prudent to envisage some form of “agency committee” which monitors the funding during the provision of the MICE equipment. There has been no mention of MICE operating funds—a common fund? RAL?As stated above, it is planned to create the “agency committee” either by expanding the membership of the Joint Project Board or by creating an equivalent body. Initial contacts with the relevant funding agencies in Europe, the US and Japan are in the process of being made.It is planned to have a common fund to cover elements of the installation of MICE, running and dismantling. Initial ideas for this were presented to the MICE collaboration meeting at the end of March and a first proposal will be made by mid-May. This fund will managed through RAL.