Slow controls and instrumentation of MICE

Slow controls and instrumentation of MICE Physics and systematics How the state of the cooling channel gets defined Engineering for the signal readout Data Record M. A. Cummings Feb. 25 2004

Alain’s physics lecture Mice fiction in 2007 or so…. . MICE measures e.g.(eout/ ein)exp= 0.904 ± 0.001 (statistical) and compares with(eout/ ein)theory. = 0.895 um, okay.. Could we understand this???. SIMULATION experimental systematics: modeling of spectrometers is not as reality theory systematics: modeling of cooling cell is not as reality REALITY MEASUREMENT Correct geometries TRIUMF data Beam diagnostics Proper emittance population Tracking and particle ID Cooling channel systematics

Systematics assumptions and questions • Stated Goal: eout/ein 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.

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 density Magnetic field RF field Calibration: Magnetic fields: Offline field maps Fringe fields Survey/alignment Tracking with online monitoring Subsystems Absorbers RF Magnets

Cooling channel readout: design Cooling channel component state (physics) Temperature inside the the absorber/vacuum Pressure on the LH2 outlet Magnetic field measurements: currents (probes) power supply location 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 Helium Optical occlusion methods (laser or non-laser) Design considerations (depends on the final dimensions, routs, ports) LH2/flammable gas safety Clearance and strain relief Feedthroughs to outside electronics Noise cancellation/shielding Robustness

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 Is this the right approach now?

A. Blondel, TB talk The magnetic measurement devices as from the proposal see pages 52, 53. : 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 F.Linde@nikhef.nl and filthaut@hef.kun.nl ) NB, we need to know *where* the probes are for this to work

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

From A. Blondel TB talk: 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 D(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

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(f) 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)

Slow controls and instrumentation of MICE