Nominal settings as of 1 Sept 2005
- fixed up repetition/ambiguity in alignment procedure section
- adjusted nominal positions of F0H,F1H, and F2H according to
quad-off alignments.
Nominal settings as of 1 Nov 2004
- 29.6 Tune updated based on B2 scan results
Nominal settings as of 29 October 2004
- 29.6 Tune updated based on TEC measurements
Nominal settings as of October 2004:
- 29.6 Tune was unchanged from 2003
- 32.8 Tune was unchanged from 2003
- added tunes for translational and rotational alignment
_________
BEAMLINE:
Log on to ccssup1 as follows:
>ssh -l twist ccssunp1
with the usual password. Then type "m13 &" to get the EPICS displays.
In the subdirectory twist_save are saved tunes in .snap files.
Note that all DAC settings can be found by looking at the .snap files
(which are just text files).
There are two values which should roughly agree for each magnet, the
"scaled setting" (just the DAC converted by a linear expression) and
the "scaled readback" (the controls system ADC output, also converted
to current).
The DAC is an integer telling the power supply current to set.
The beam line settings are conveniently shown by the "u_Beam" page of
the StatusBar. It has the two above current estimates, plus the DCT
readback which should be quite precise compared to the other two.
For the dipole magnets (B1 and B2), trust the NMR above all else.
In any case, if there was disagreement with anything please state this
in the elog.
PLEASE POST A SNAPSHOT OF THE u_Beam WINDOW TO ELOG after setting the
tune.
_____________________
Precision of Settings:
- B1 and B2 should be adjusted using coarse DACs until they are within 0.2G of
the value you want. Then set the regulators from MIDAS status to values you
want the field to go to.
- Slit/Jaw positions and widths should be adjusted until within 0.1mm of
the tune specifications
===SETTINGS FOR 29.6 MeV/c SURFACE MUONS:
M13 Absorber position: 0
Gas Degrader setting: He=70% (CO2=30%)
(Wait 90 minutes for the degrader to flush.)
Filmstrip Degrader setting: 1 (open hole)
Magnet settings file: m13dev_29p6.snap
Set to precision +/- 0.1 mm (width w and position p)
F0 V jaws: w=18 mm
F0 H slits: w=60 mm, p=-2.0 mm
F1 H slits: w=10 mm, p=-3.9 mm
F2 V jaws: w=20 mm
F2 H slits: w=12 mm, p=+1.6 mm
DAC/DCT/NMR values (Oct 14 2005)
B1: 2584(500)/39.80A/871.30G
B2: 2948(500)/44.56A/946.1G
(NMR range 1)
Q1: 628/149.76A
Q2: 7723/57.41A
Q3: 651/113.21A
Q4: 749/89.47A
Q5: 648/113.36A
Q6: 440/52.15A
Q7: 493/59.56A
Trigger: M
===SETTINGS FOR 32.8 MeV/c:
M13 Absorber position: 0
Gas Degrader setting: He=75% (CO2=25%)
Filmstrip Degrader setting: 9 (20 thou)
Magnet settings file: m13beam_32p8ch1.snap
Set to precision +/- 0.5 mm (width w and position p)
F0 V jaws: w=12 mm
F0 H slits: w=40 mm, p=-2.0 mm
F1 H slits: w=10 mm, p=-3.9 mm
F2 V jaws: w=20 mm
F2 H slits: w=12 mm, p=+1.6 mm
DAC/DCT/NMR values (Oct 31 2003)
(need revision!)
B1NMR: 2876/44.17A/965.5G
B2NMR: 3283/48.98/1052.7G
(NMR range 1)
Q1: 696/166.10A
Q2: 8558/63.67A
Q3: 721/125.86A
Q4: 830/99.21A
Q5: 718/125.96A
Q6: 488/57.93A
Q7: 546/65.46A
Trigger: M
===SETTINGS FOR 120 MeV/c PIONS (SPRAY):
M13 Absorber position: 3
(setting for 0.005" mylar on new absorber wheel inserts;
prior to 2004, we used 0.0065" CH2 at position 1)
Magnet settings:
m13dev_120_spray.snap
Set to precision +/- 0.5 mm (width w and position p)
F0 V jaws: w=12 mm
F0 H slits: w=40 mm, p=-2.0 mm
F1 H slits: w=10 mm, p=-3.9 mm
F2 V jaws: w=20 mm
F2 H slits: w=12 mm, p=+1.6 mm
NMR values within a few percent of these should be fine for spray
tunes...
DAC/DCT/NMR values (Nov 15 2003):
B1NMR: 10649/163.02A/3532.5G
B2NMR: 11898/179.39A/3851.5G
(NMR range 3)
All quads off except Q1 and Q2.
Q1: 1000/238.03A
Q2: 33000/246.35A
Gas Degrader setting: Doesn't matter.
Trigger: DS, or MLT. (Usually some runs with each.) DS scintillators
do not work if they are close to the yoke if the solenoid is on ...
leave 50 cm space or so.
===SETTINGS FOR TRANSLATIONAL/ROTATIONAL ALIGNMENT ( 4 settings )
http://midtwist.triumf.ca:8081/EL/040903.4417?exp=twist
1) 4 runs as run 17484
2) 4 runs as run 17485
3) 15 runs as run 17486
4) 15 runs as run 17487
---> 1) and 4) 120 MeV/c PIONS (SPRAY), B2 -3.75%:
http://midtwist.triumf.ca:8081/EL/040903.3282?exp=twist
---> 2) and 3) 120 MeV/c PIONS (SPRAY), B2 +1.9%:
http://midtwist.triumf.ca:8081/EL/040903.3792?exp=twist
M13 Absorber position: 3
(setting for 0.005" mylar on new absorber wheel inserts;
prior to 2004, we used 0.0065" CH2 at position 1)
Magnet settings:
m13dev_120_spray.snap
Set to precision +/- 0.5 mm (width w and position p)
F0 V jaws: w=40 mm
F0 H slits: w=40 mm, p=-2.0 mm
F1 H slits: w=10 mm, p=-3.9 mm
F2 V jaws: w=150 mm
F2 H slits: w=30 mm, p=+1.6 mm
NMR values within a few percent of these should be fine for spray
tunes... for alkignment data, check occupancy histograms to make
sure that extremes of U and V are populated.
DAC/DCT/NMR values (Sep 3 2004):
B1NMR: 10649:207/162.25A/(no NMR at this range)
B2NMR: 11450:226/170.17A/3851.5G (-3.75%, for 1 and 4)
B2NMR: 12125 (+1.9%, for 2 and 3)
(to make DS rate ~2kHz)
NMR range 3
All quads off except Q1 and Q2.
Q1: 1000/238.03A
Q2: 33000/250.46A
Gas Degrader setting: Doesn't matter.
Trigger: DS for 1) and 2), and PU for 3) and 4)
===SETTINGS FOR 1AT1 TARGET SCANS:
TURN ALL HV OFF!!!
(Do this before any other changes here, or the chambers could be
damaged!)
M13 Absorber position: 0 (empty hole)
Filmstrip degrader position: 1 (empty hole)
Magnet settings: same as for 29.6 MeV/c.
Slit settings:
F0 V jaws: w=150 mm
F0 H slits: w=150 mm, p=0 mm
F1 H slits: w=120 mm, p=0 mm
F2 V jaws: w=120 mm
F2 H slits: w=150 mm, p=0 mm
Gas degrader setting: doesn't matter.
Trigger: None (no data).
________________
HV & THRESHOLDS:
DC's:
HV: 1950 V
Threshold: -150 mV
Outer PC's:
HV: 2050 V
Threshold: Ganged wires: -300 mV
(C0:1,4,5,8;C5:5,8,9,12,13,16,17,20;C10:17,20,21,24)
Central wires: -250 m
(C0:2,3,6,7;C5:6,7,10,11,14,15,18,19;C10:18,19,22,23)
Target PC's:
HV: 2050 V
Threshold: -150 mV
Groups used in efficiency scans:
DC Planes in Group A:
1,2,5,6,9,10,13,14,17,18,21,22,25,26,29,30,33,34,37,38,41,42
DC Planes in Group B:
3,4,7,8,11,12,15,16,19,20,23,24,27,28,31,32,35,36,39,40,43,44
PC Planes in Group A:
1,2,5,6,9,10
PC Planes in Group B:
3,4,7,8,11,12