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 F.Linde@nikhef.nl and filthaut@hef.kun.nl )

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)