[esa-t474] [Fwd: Fwd: T-474 plan]

[Bino Maiheu]

-------- Forwarded Message --------
From: Yury Kolomensky <YGKolomensky at lbl.gov>
To: Bino Maiheu <bino at hep.ucl.ac.uk>
Cc: Yury Kolomensky <YGKolomensky at lbl.gov>, Stewart Boogert
<sboogert at pp.rhul.ac.uk>, Michael B. Woods <mwoods at slac.stanford.edu>,
Mike Hildreth <mikeh at omega.hep.nd.edu>, Krishna Kumar
<kkumar at physics.umass.edu>
Subject: Fwd: T-474 plan
Date: Mon, 5 Mar 2007 09:42:02 -0800

	Hi Bino,

could you please forward this to T-474 list ? I guess we can have a 
discussion of the plan first in two mins.

- BPM Calibration

(1) ESA BPM calibration with helmholz coils (A34 ?), run in dithering 
mode (E158CALI): 3-point scan -20 G-m, 0, 20 G-m, 2-10 pulses at each 
point (have to determine if this is compatible with feedback). Two 
modes: long calibration (15 mins), 0.1% precision, and short 
calibration (2 mins) -- <0.5%.

(2) Mover calibration (5 points, from -0.5 mm...0.5 mm, 10 sec/point), 
2 BPMs

(3) Phase ramp run (energy part of E158DITH -- 3 points, +/- 0.5% if 
possible, 2-10 pulses at each point, 2 mins).

Each setpoint on the coil, phase ramp, and mover would write a value to 
a dedicated ADC channel.

So the sequence is:

Helmholz X (2-15 mins)
Helmholz Y (2-15 mins)
Phase Ramp (2 mins)
Mover X4 (2 mins)
Mover Y4 (2 mins)
(add X6/Y6 when it's installed)

Total: 40-60 mins (depending on efficiency). Repeat every 4 hours.

This does not define how we calibrate BPMs 28,31,32. I think we can use 
well-calibrated BPMs in ESA and extrapolate upstream (with Q30/Q38 
off). Occasionally (e.g. for T-480 or once per shift), should do 
corrector A28/A29 scan with Q30/Q38 off (calibrate BPMs 31/32). Use 
current BPMCali for this. This is to check that extrapolation from ESA 
is reliable.

**** Action item: would like to check how extrapolation works early in 
the run. Bino or Mark ?

- Spectrometer B-field scan: 3 pt scan (-B, 0, +B), 30 sec at each spot 
(will have to look how quickly the magnets settle). Run once an hour on 
polarity switch.

- Normal running sequence:

	- Switch to -B
	1) Long BPM Calibration (1 hour)
	2) Run at -B (1 hour)
	- Switch to 0 B
	3) Short BPM Calibration (20 mins)
	4) Run at 0 B (20 mins)
	- Switch to +B
	5) Short BPM Calibration (20 mins)
	6) Run at +B (1 hour)

Total: 4 hours, repeat twice per shift.

Other issues:

1) Magnet standardization. Need Ray et al to define the procedure. 
Standardize after every magnet trip
2) Magnetic field changes. Need Ray's input on this. I assume we are 
always changing field from -B to +B, then all the way to -Bmax, and up 
to -B. Need to define Bmax, ramp rate, etc and program into the magnet 
control.

**** Action item: look at the existing magnet data to determine the 
stability of B fields, ramp speed, etc. Bino ?

Any other issues ?

Yury
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