1. INTERIM REPORT on MANX after MICE
Preamble
Several presentations related to the uses of the MICE infrastructure after MICE PHASE II were made at CM22.
The MICE executive board “concluded that it would be god (sic) if a smaller group of MICE physicists would take the time to go through these various proposals (by any means they see fit1) and answer specific questions which are within our competence as MICE and produce a short report ”.
The question “which is the most relevant R&D program after MICE’’ was excluded as not being within MICE competence.
1 Waterboarding was excluded
MANX interim CM23
January 2009

2. Scope Committee The questions suggested by the EB were:
Space-consistency in the MICE hall
Scope and adequacy of proposals in view of existing
MICE instrumentation, and
Infrastructure
Consistency of time scales
Comment on resources available from MANX and MICE
Good use of MICE infrastructure resources
Committee
John Cobb (chair)
Chris Rogers
Malcolm Ellis
Yoshi Kuno
keeping the MICE Spokesman informed
MANX interim CM23
January 2009

3. After consulting the MICE spokesman it was decided that MANX was the most developed current proposal and that the committee should concentrate principally on MANX.
Nevertheless there are other possible experiments which could use some or all of the MICE infrastructure, and these should be considered similarly in the near to medium term.
Initial information about MANX was obtained from the latest MANX proposal [1], supplemented by specific questions to the MANX spokesman (R. Johnson).
[1]
MANX interim CM23
January 2009

4. BRIEF MANX OVERVIEW
3 m long He-filled Helical Cooling Channel  6D cooling
Two possible configurations
‘With Matching’
Requires extra matching sections
‘Off-axis’
Inject & extract beam at an angle
MANX interim CM23
January 2009

5. MANX CONDITIONS & INSTRUMENTATION
From MANX proposal:
350 MeV/c muons in  150 – 200 MeV/c out
Longitudinal momentum measurements by Hi-res TOFs
Up- & Down-stream
~4pSec resolution using MCP PMTs
Being developed
HCC interspersed with fibre tracker planes
Expect factor ~2.5 (6-D) cooling in 3m HCC
Starting from 40mm transverse emittance & 8m longitudinal
>> Largest MICE emittance of ~10mm
What is performance for ‘standard’ MICE beams?
Including internal fibre planes
What resolutions are required?
Factor 2.5 (in 6D) comes from lowest figure of Fig4, P14 of proposal, starting from 40mm transverse, 8m (???!!!) longitudinal
MANX interim CM23
January 2009

6. OFF-AXIS MANX Smaller experiment – no matching sections
Presumably requires
N periods to be all in one plane (?)
Smaller experiment – no matching sections
More money for cooling rather than matching
But 50% losses into downstream spectrometer
MANX also considering 0.5m matching sections
One end close to iron shield wall
Space for services close to wall?
Possible large error fields?
Magnetics & Forces
Transfer of non-axial magnetic/quench forces
Torques on Spectrometer coils
Not designed for these
Probably ‘Show Stoppers’ & did not consider OAM further
MANX interim CM23
January 2009

7. SPACE CONSISTENCY – MATCHED MANX
HCC cryostat
No detailed dimensions available
HCC is 3m x ~0.5m radius
Should fit – but service turrets etc ??
HCC + Matching
Longer overall
Possibly need to extend false floor a few m
Cryogenics
Cryo. system not specified (tankers?)
‘Considering using left-over cable from SSC for HCC; might prohibit cryocoolers’
Estimate ~2,500 litres of LHe in HCC
Space/cost for refrigerator ?
If LHe shipped in, who pays ?
TOF counters (Hi-res)
Additional space downstream
~1m for dp/p = 1%
Beam expands on leaving spectrometer
 large area TOFs ~1.2m x 1.2m (3 sigma, 5mm emittance)
Implications for size of downstream PID
Mucal (EMR) etc.
Beam has beta = b0 = 33cm in solenoid
Expands in drift as b = b0 + s^2/b0
So rms size is sig(x) = sqrt(b epsn*m/p)
Say s = 100cm, eps = 3mm so
Sig(x) = sqrt((33+100^2/33)*0.3*106/150) = 14.9cm for eps=3mm
So +/- 3 sig(x) 2 x 3 x 14.9 = 89cm for 3mm
And ~~ 115cm for 5mm
MANX interim CM23
January 2009

8. SCOPE & ADEQUACY of INSTRUMENTATION
Resolutions required ?
Transverse
What is MANX criterion for (deps)/eps?
What is expected performance with
standard MICE beams of 3, 6, 10mm?
(Esp.with internal HCC tracker planes.)
10mm is ~maximum beam emittance
Longitudinal
Proposal says dp/p of 1% for pl
New 5pSec TOFs for longitudinal
momentum measurement
Estimate 2D cooling for 350  150 MeV/c
Equilibrium emittance ~ 2.2mm
10mm  5.5mm = 45%
3mm  2.5mm = 16%
MICE spectrometers probably more
than adequate for transverse planes
What does ‘longitudinal’ mean if no RF?
Would like to understand goals better
Equilibrium emittance = (X0 dE/dX of H2)/(X0 dE/dX He) * beta = 33cm / beta = 42cm * (about) 2mm for equilibrium emit of H2 in MICE
Estimate final emittances as e2 = e0 + (e1-e0)*(p2/p1)
dp/p from timing
dp = (c/L)*E*(p/m)^2 dt
MICE tofs give dp = 2MeV/c at 200 MeV/c
P dp dp/p % % % %
Don’t understand what longitudinal cooling is with no RF bunches
Simply reduction in momentum spread???
MANX interim CM23
January 2009

9. SCOPE & ADEQUACY of INSTRUMENTATION - 2
TOFs
Upstream PID
MANX considering new
Cerenkovs
Downstream PID
Downstream momentum
MICE upstream TOFs with 8m give dp/p of
200 MeV/c
350 MeV/c
+ ~3MeV/c straggling in TOFs
Degraded by diffuser (15mm Pb) – how much ?
Estimate additional ~3 MeV/c
Expect worse pi/mu 350 MeV/c
MICE Cerenkovs designed for <= 240 MeV/c
Is downstream PID adequate for higher pi/mu ratio?
(don’t know; really for mu / e anyway)
Hi-res TOFs
 ~1m extra space downstream of spectrometer
Downstream PID detectors must be larger
Gas-filled TPCs in place of fibre tracker?
(save some space)
MANX interim CM23
January 2009

10. MICE INFRASTRUCTURE – BEAM
Operation at 350 MeV/c
Somewhat unknown territory
D1 can give 480 MeV/c
Have run D2 up to 450 MeV/c for protons
Mu’s from forward pi decays (?)
Worse pi/mu ratio, probably (?)
Useful muon rate?
Probably possible
‘can be studied by MICE within the next few
months after the decay solenoid works’
(depends on other MICE priorities)
MANX interim CM23
January 2009

11. INFRASTRUCTURE – SPECTROMETERS
Matching
Beta HCC matching section
~33cm
Upstream field ~6T
May have to increase Match Coil currents
Estimate ~ 350/200 = 1.75
Probably cannot be done with current design
which is ‘good enough’ for MICE
Needs evaluation
Possible show stopper
Engineering
Margins of match coils – little in hand
Forces – go like B^2
How to transfer?
Could matching be done with extra match coils
(as well as MANX matching sections)?
 even longer channel; not nice
MANX interim CM23
January 2009

12. INFRASTRUCTURE – 2 Shielding / Stray fields
HCC is not symmetric (6T  3.5T)
Is shielding adequate for 6T?
Larger fields in Hall
Effect on other equipment?
Asymmetric error fields?
Effect on performance (if any)?
Needs evaluation
LH2
MANX could use it:
‘Would be better experiment but
engineering issues’ (RJ)
HCC is 3m long x 50cm radius ~2,500 litres
~ 40 x MICE LH2 volume
Unlikely MICE LH2 systems could cope
Would need different systems for LHe
MANX interim CM23
January 2009

13. INFRASTRUCTURE – 3 RF systems Not required; no plan to use them
Could be removed to make space
Use for ??
DAQ
Expand for HCC tracker planes &
Hi-res TOFs
Space in MCR / racks?
Software
Assumed that MICE software will be
sufficient
Yes, but…
(a) Needs adapting for specific
MANX detectors
(b) Need to use something now
to demonstrate goals & feedback to
engineering
Upstream part of Hall / Beam
Probably no change
D1 can go to 480 MeV/c
D2 can go to 450 MeV/c
MANX interim CM23
January 2009

14. TIMESCALES Plan to follow MICE in 2013 ‘Mount within ~1 year of MICE
finishing whilst expertise available’
HCC would take ~4 years to
engineer, design & build
 2013 if started now
1 year to install
No engineering design for HCC;
No simulation in MICE context
Need to demonstrate engineering,
develop Hi-res TOFs, … within about two
years.
Seems challenging – despite savings in
infrastructure & detectors – cf time from
MICE LOI / Proposal to now ~8 years
Requires engineering resources soon and
substantial interaction with MICE experts (if
available)
Timescale seems rather optimistic
MANX interim CM23
January 2009

15. EFFORT NEEDED Simulate MANX Software Engineer & build Demount MICE
Mount MANX
Some assumptions that MICE has
resources available to contribute to MANX
MANX proposal has 34 signatories;
MICE is already stretched on some fronts
Resources look very tight
Run MANX
Maintain:
Target
Beamline
Decay Solenoid
MICE detectors
DAQ
Software…
Estimate ~9 FTE simply to maintain MICE
infrastructure and instrumentation fairly
comfortably
MANX interim CM23
January 2009

16. SUPPORT – Stating the obvious, perhaps
MANX proposal assumes much of MICE will exist
MICE is a collaboration
Infrastructure is not (yet) a facility
Operated by MICE collaborators
Instrumentation is not owned ‘in common’ by MICE
Owners of instrumentation may have own preferences or funding agency constraints
‘MICE’ itself cannot agree to support any new initiative
MANX – or any new cooling experiment – at RAL would probably require substantial UK involvement
RAL is small part of MICE
Not same relationship to users as CERN or Fermilab
MANX interim CM23
January 2009

17. SUPPORT
Straw poll of some members of MICE with some responsibilities for infra-structure or instrumentation was conducted in order to obtain an idea of support for a non-specific future experiment & indication of attitude of funding agencies. It was indicated that ‘No comment’ would be a valid response. (Five still to reply.)
Responses (paraphrased) :
‘No comment…, sine qua non to finish MICE ’
‘Will discuss & respond shortly’
‘Difficult to foresee future; …will consider’
‘Would hand over [ ] to RAL; involvement would depend on details of experiment’
‘Would support… if MICE supports & US supports strongly’
‘NF is important; would support [infrastructure] & recruit’
‘Probably welcomed by STFC… support the development of a proposal for an appropriate and realistic experiment with enthusiasm …Hall… & UK contributions… would be available’
Qualified support; STFC would most likely support a new initiative. Would require UK & other groups to agree on a program & apply for new funding.
Significant inverse correlation between degree of support and distance to RAL!!!
MANX interim CM23
January 2009

18. ADAPTING MANX to MICE 3m MANX not well matched to MICE instrumentation
Shorten MANX
MICE instrumentation should work 150 – 240 MeV/c
Shorten MANX to ~1.5m
240 MeV/c in  150 MeV/c out (v. roughly):
Should still be plenty of cooling
Would ease upstream PID
Would ease matching & engineering
Match into 4 Tesla instead of 6 Tesla
Smaller He requirements
~1300 litres
Still large; still couldn’t use LH2 systems
Downstream TOFs would still require space & area (~1m2)
Use TPC instead (?)
MANX interim CM23
January 2009

19. SUMMARY (1 / 2)
Off-Axis MANX may have engineering difficulties associated with transfer of non-axial forces, and torques on the spectrometer cold masses; it was not considered in detail.
Matched MANX has no obvious space incompatibilities; the space required for the helium system needs to be assessed.
The MICE LH2 systems would be too small for a LH2-filled HCC; the RF systems would be redundant.
The resolutions required by MANX are not precisely specified but the MICE spectrometers appear more than adequate for transverse measurements; the TOFs could provide a momentum resolution of 1% at 200 MeV/c to 3% at 350 MeV/c, but degraded by straggling.
The Cerenkovs would not be adequate at 350 MeV/c. The down-stream PID detectors may be too small, given the space required for the downstream TOFs for longitudinal momentum measurements.
MANX interim CM23
January 2009

20. SUMMARY (2 / 2)
Engineering considerations (margins and forces) suggest it may not be possible to operate the MICE spectrometers to match into the 6T HCC field required for an input beam of 350 MeV/c. [To confirm]
A shortened MANX, using a 240 MeV/c input beam, could be a better match to the MICE instrumentation.
If the MICE software is to be used for MANX some effort should soon be devoted to its adaptation and use to demonstrate the performance of MANX with the MICE (or other) instrumentation.
The effort required to design… and install MANX, and to maintain the MICE infrastructure and instrumentation should be quantified. The timescale looks rather optimistic, given the available resources.
There is some support within MICE, with qualifications, for a (non-specific) second generation experiment at RAL; a strong UK presence would be necessary. MICE itself could not agree to any next experiment; a new collaboration would be required.
MANX interim CM23
January 2009

21. THE END
MANX interim CM23
January 2009

22. MANX interim CM23
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23. MANX interim CM23
January 2009