Slow controls and instrumentation of MICE
1. Physics and systematics2. How the state of the cooling channel gets
defined3. Engineering for the signal readout4. Data Record
M. A. Cummings Feb. 25 2004
Alain’s physics lecture Mice fiction in 2007 or so….Mice fiction in 2007 or so….
. MICE measures e.g.. MICE measures e.g. ((outout inin))expexp = 0.904 = 0.904 ± 0.001 (statistical)± 0.001 (statistical)
and compares withand compares with ((outout inin))theorytheory. . = 0.895 = 0.895
um, okay.. Could we understand this???.
SIMULATIONSIMULATION
REALITYREALITY
MEASUREMENTMEASUREMENT
theory systematics: modeling of cooling cell is not as reality
experimental systematics:modeling of spectrometers is not as reality
Correct geometriesTRIUMF data
Beam diagnosticsProper emittance populationTracking and particle IDCooling channel systematics
Stated Goalout/in of 10 –3
Assume there will be a standard (or agreed to) definition of 6-D cooling.
What are the beam diagnostics concerns in a single particle experiment? How is beam diffusion controlled? Backgrounds?
We can also assume that the tracker can give us precision particle position and momemtum that this won’t contribute significantly to the error.
Particle ID < 1% error
The sources of systematic errors in the COOLING CHANNEL need to be under control to a level that 10 independent sources will be < 10-3 the same level
A. Blondel: goal to keep each source of error <3*10-4 level if at all possible.
Systematics assumptions and questions
Instrumentation and controls Beam diagnostics: Dipoles, “twiss” params, halo, etc. Monitoring/safety: LH2 controls, RF, Magnets, cryogenics
•“slow” ~ 1 Hz Data acquisition: information on each event
• Information on system state: dE/dx densityMagnetic fieldRF field
Calibration:•Magnetic fields:
Offline field mapsFringe fieldsSurvey/alignmentTracking with online monitoring
Subsystems•Absorbers•RF•Magnets
Cooling channel readout: design
Cooling channel component state (physics)Temperature inside the the absorber/vacuumPressure on the LH2 outletMagnetic field measurements:
currents (probes)power supplylocation monitors
RF: power, tuning, phase Controls ( state of the system included in data record)
LH2, Magnet and RF Safety systems (subset of monitoring describing the “state” of the system)Temp/flow on HeliumOptical occlusion methods (laser or non-laser)
Design considerations (depends on the final dimensions, routs, ports)LH2/flammable gas safetyClearance and strain reliefFeedthroughs to outside electronics Noise cancellation/shieldingRobustness
Signal transfer (cooling channel) Wire and Shielding Concerns
¤ Cable plant into solenoid
• Shielded-twisted pairs (two pairs per Cernox)
– Shield drains carried from Lakeshore(s) to sensors(not grounded)
• Grounding
– Details depend on overall MICE grounding scheme
¤ Common mode (surges) due to magnets
• Need to protect electronics without burning barriers
¤ Noise/sensitivity issues Feedthroughs
¤ Vacuum compatible, electrically insulated
¤ Have to decide pin configuration based on 2, 4 wire readouts
¤ Commercially available ..MDC vacuum products
Experimental controls channel list
what info source how many channels who determines
Beam diagnostics ? Tilley/Palmer
Tracker/ particle ID Bross/Bonesini
Magnetic Fields 50 Rey/Guyot
Alignment 50 Black/Linde
Slow controls ? Baynham
RF ? D. Li
Magnets 10 *3 Green
Absorbers 20 *3 Cummings
Is this the right approach now?
SC Coils
Magnetic
sensors
3 hall probes
Positioning holes
The magnetic measurement devices as from the proposalsee pages 52, 53.
NB, we need to know *where* the probes are for this to work
:The magnet system will be operated in a variety of currents and even polarities and it is difficult to assume that the field maps will simply be the linear superposition of those measured on each single magnet independently: forces are likely to squeeze the supports and move the coils in the cryostats.
we will measure the magnetic field with probes (NIKHEF) (contacts Frank Linde and Frank Filthaut [email protected] and [email protected] )
A. Blondel, TB talk
Global monitoring and experiments
Want to record a full configuration of the experiment at every “pulse”.
Pulse = trigger = ? Will be running with different configuration of calibration
run in order to get a handle on the systematics:¤ With RF, no beam¤ without RF, beam ¤ without any ¤ with both RF and beam.¤ With magnets no absorbers¤ With magnets one absorber ¤ Magnets, with and without RF
Want to start understanding the tolerances needed for emittance measurement
Example of such: Coil tilt tolerance.
Take U. Bravar's MICE note 62:
this looks like a quadratic dependence.
it takes 40 =0.068 rad to get a change by 0.065
==> it will take (tilt) = 0.068rad x sqrt(0.001/0.065) to get a change by 0.001
this is 8mrad or 0.5 degrees.
this sensitivity is (3x) smaller than the tolerance calculated by U. Bravar, because MICE will be sensitive to effects that are somewhat smaller than what is assumed to be needed for the cooling channel.
similarly for the transverse position I find ~6mm tolerance instead of 20mm
From A. Blondel TB talk:
quantity design tol. monitoring with beam / exp. conf
beam optics
transfer matrix: for ex.(pt, pL, phi, x0 , y0)in <-> (pt, pL, phi, x0, y0)out
measure with no RF and empty absorbers each time one changes the mag set-up.
positions of coilsinternal survey
some mm alignment
position monitor
currents some 10-4 amp-meterposition monitoring
mag field some 10-4 mag probes
amount of absorber (in g/cm2)
3*10-3 = 1mm/35 cm
density through T & Pthickness ..Optical occlusion?
measure energy loss of muons for 0 absorber, 1 absorber, two absorberswith RF off.
RF field 3 10-3 measure E to dE/E= 3.10-3
Measure phase
measure energy of muons vs RF phase before and after cooling channel
What physics controls can we define? How can we control it by design tolerances / by monitoring / with
the beam itself
example of such an experiment Eout -Ein (GeV) simulated by Janot in 2001(nb: this was at 88 MHz) …
this measures ERF(t) ERF() dependence…
So far…the required monitoring should consist of:
-- Ampermeter for each coil-- Magnetic field measurement -- monitor position of probes and coil assemblies (with
ref. to an absolute coordinate system)-- ERF(t) (gradient and phase of each cavity)-- absorber density (i.e. T & P) and thickness. -- Beams-- Cryo
Look toward how we do this in a neutrino factory
Want to get information unique to this cooling experiment
e.g. the muons themselves will provide very powerful cross-check (energy loss and energy gain, transfer matrix)