Hello.
I have written a very point-form summary of the data logged on the new T1 
protect monitor during our Fall 2000 beams running period.

Regards,
Tracy Porcelli

Summary of Occurrences in the Fall 2000 Running period for New Protect Monitor

The new T1 protect monitor which has a 5mm separation between top/bottom
plates, with a 4mm separation between left/right plates was installed into
the beam line on October 18th. The target ladder in which this monitor is
mounted was removed (changed to the spare target ladder) on November 24, 2000.
Note: the profile monitor which was planned to be used to determine a proton 
beam profile at the T1 target was not in working condition on either of the 
target ladders and thus could not be used in the Fall run period.

Calibration Scans of the T1 Protect Monitor

Wednesday October 18, 2000:
The results of this scan made no physical sense.

Wednesday October 25, 2000:
Scan was performed with beam in pi+ mode and with proton beam current at ~1
microamp. Two scans of the bottom/top plates were performed and the average
calibration was 20.2 dac/mm. Three scans of the left/right plates were
performed and the average calibration was 133 dac/mm.

Friday October 27, 2000:
The 1AM6.6  beam line monitor which resides upstream of T1 and the T1 protect
monitor was used to infer a beam profile. Roughly speaking the FWHM(horizontal)
of the proton beam=2.6mm and the FWHM(vertical)=3.9mm. Caution: the beam is not
meant to be focussed at 1AM6.6 and thus this is not necessarily the proton beam
profile at T1. 

Monday October 30, 2000:
The 1AM6.6 beam line monitor was used again. Results gave FWHM(horizontal)=
2.8mm and FWHM(vertical)=3.9mm.
Scan of T1 protect monitor was performed with beam in pi- mode. Calibration of
bottom/top plates gave 22.7 dac/mm. Calibration of left/right plates gave
95 dac/mm.

Wednesday November 8, 2000:
Scan of T1 protect monitor was performed with beam in pi- mode and RF booster
on. Calibration of bottom/top plates gave 21.4 dac/mm. 
Calibration of left/right plates gave 89.9 dac/mm.

Wednesday November 15, 2000:
Scan of T1 protect monitor was performed with beam in pi- mode.
Calibration of bottom/top plates gave 21 dac/mm. Calibration of left/right
plates gives 94 dac/mm.

Conclusions:
The calibration of the monitor is different for the beam line configured to
pi+ or pi-. Not only does the calibration number itself change but the range
over which the plates plateau are different.
For pi+ mode, top/bottom plates, span is -200 to 200 dac units.
For left/right plates, span is -600 to 400 dac units.
For pi- mode, top/bottom plates, span is -150, to 150 dac units.
For left/right plates, span is -450 to 250 dac units.

Note: From the target scans we would need a minimum of 0.03 of a normalized
signal from either the left or right plates to be able to use the calibration
tables. So for a 100 microamp beam we would need to be reading around 3 micro
amps on one of the plates!
UG!!!: data taken with the old protect monitor with a 5mm separation at
140 microamps showed 2microamps on the right plate and 1microamp on the left 
plate (June 29-July 4, 2000).

Data logged on the T1 Protect Monitor

October 20-21, 2000:
Beam current 90-100 microamps and in pi- mode.
Signals on left plate 1.0-1.8 microamps. 
Signals on right plate 1.0-2.3 microamps.
However, they have a 1.0 microamp offset when beam current goes to zero.
Beam vacuum seemed stable. Left/right plates track with dac.
Dac values for TW60, TW61 around 0.05.

Ops Meeting Minutes:
Difficulty in establishing high current down BL1A after new ladder installed.
Profile monitor not working. Compromised tune left in place until experts could
investigate. Then began a series of RF problems. From Oct 20 through Oct 22
steady but bimodal production: 100 microamp to 1A when inflector well behaved
and 80 microamp when in bad mode where cyclotron transmission dropped by 10%.  


October 23-24, 2000:
Beam current 80-90 microamps and in pi+ mode.
Signals on left plate 1.0-1.2 microamps.
Signals on right plate 1.2-1.8 microamps.
However, when beam goes off signals on left/right plates increase--ground loop
problems in the electronics.
Beam vacuum stable. 
Dac values for TW60, TW61 between 0 and 0.007.
October 24-25, 2000:
Beam current 90-100 microamps and in pi+ mode.
Signals on left plate stable and read 1 microamp but never zero when beam off.
Signals on right plate stable and read 1.5 microamp and do creep down to zero.
Beam vacuum stable.
Dac values for TW60, TW61 between 0 and 0.007.
October 25-27, 2000:
Beam current 100 microamps and in pi+ mode.
Signals on left plate small negative and go small positive when beam off.
Signals on right plate 0.3-0.5 microamps and go to zero when beam off.
Beam vacuum stable.
Dac values for TW60, TW61 mostly zero except for some small spikes.
October 27-31, 2000:
Beam current 130-140 microamps, in pi+ mode but changed Oct 28 to pi-.
Signals on left plate small negative but go to zero when beam off.
Signals on right plate 0-0.4 microamps.
Beam vacuum stable.
Dac values for TW60, TW61 zero and then around 0.5.

Ops Meeting Minutes:
Oct 23 see inflector now operating in continuously bad mode.
Oct 24 some time spent attempting to switch to pi- mode, but unsuccessful due 
to BL1A target controller and RF problems. 
Oct 25 sees inflector problem tracked down to bad cable. No more bad mode but
still 2kV difference in the sum of the inflector voltages
due to a slightly different spacing of the electrodes after it was rebuilt 
and reinstalled. Found a ground loop in the electronics connecting the T1 
protect monitor. Problem fixed and amplifiers re-zeroed. 
Oct 26 some time spent improving pi- tune and some problems with RF voltage
stability.
Oct 28 (talked with Fred Bach) and because RF booster is off and the injector 
problems occurring mean the tune we are running with is NOT THE STANDARD TRIUMF
tune. It is narrower.

October 31-November 1, 2000:
Beam current 100 microamps, and in pi- mode.
Signals on left plate read zero all the time.
Signals on right plate 0-0.4 microamps.
Beam vacuum stable.
Dac between 0.5 and 0.52.
November 1-7, 2000:
Beam current 130-140 microamps, and in pi- mode.
Signals on left plate read zero or small negative values.
Signals on right plate read zero to 0.5 microamps.
Beam vacuum mostly stable except for 2 times in which vacuum rose. The effect
on the plates is directly correlated and all 4 plates showed a quite large 
signal for this duration of time. Direct evidence of how the beam vacuum 
effects the signals on the plates.
Dac between 0.5 and 0.52.

Ops Meeting Minutes:
Nov 1/2 RF booster conditioned to 110kV and new 1AT1 graphite target selected.
However 1AT1 halo was too big with the RFB on so this device was left off.
Nov 3 trying to sort out 1AT1 halo problem with RFB on. ISIS was targeted since
tune there had been compromised to minimize effects of the inflector stability
and although eventual ISIS tune was still somewhat different to a "standard"
high current one (perhaps because of a change in the inflector geometry) it was
much closer to normal than before and solved the 1AT1 halo problem. It was
noticed that the tuning was tighter  than usual but good cyclotron 
transmission.
Nov 5 some unexplained event resulted in a much poorer machine tune and needed
to go to low current/buncher off to stabilize things before returning to 
reasonable production levels.
Nov 8 (discussion with Roman Ruegg) during past week an amplifier on the left 
plate was faulty and is now replaced. He suggests proton beam is 6mm tall and
1-2 mm wide. Problems with pi+/pi- switch over is that is is affecting the beam
line upstream of T1! and it should not! 

November 9-15, 2000:
Beam current 120-130 microamps, and in pi+ mode.
Signals on left plate -0.2-0.3 microamps.
Signals on right plate 0-0.5 microamps.
Beam vacuum mostly stable.
Dac between -0.005 and 0.010.

Ops Meeting Minutes:
Nov 9 some RF downtime and a problem with ISIS RF control system.

November 15-20, 2000:
Beam current 120-130 microamps, and in pi+ mode.
Signals on left plate 0-0.7 microamps.
Signals on right plate 0-0.8 microamps.
Dac between 0 and 0.05.

Ops Meeting Minutes:
Nov 17 extended RF trouble with system fairly unstable with beam current
needing to be lowered for 3 days.
Nov 18 M13 and M11 beam blocker failed. Beam steering test for E614 revealed
that beam optics and production rate for that channel favour a 1AT1 beam spot
1 to 2 mm lower than nominal (as preferable for M11). 

November 20-26, 2000:
Beam current 100-130 microamps, and in pi- (Nov 21) mode.
Signals on left plate -0.4 to 1.0 microamps.
Signals on right plate 0-1.5 microamps.
Beam vacuum stable, then huge spikes (most likely leak), target ladder changed,
then stable again.
Dac between 0.0 and 0.5, then target ladder changed.

Ops Meeting Minutes:
Nov 20 beam current still limited by RF. Dee voltage lowered and cyclotron tune
adjusted resulting in improved RF. Overnight large tank vacuum excursion.
Beam recovered by morning.
Nov 21 An early evening pi+ to pi- switch and a subsequent 1AT1 vacuum went 
bad as 1A current was being ramped back up. Cyclotron turned off and 
investigations took place. By Nov 23 leak found at an indium seal immediately
downstream of 1AQ11.  As requested for a beam development shift the following
week, the 1AT1 target ladder was also swapped on Nov 24.
Nov 25 1A tuning underway, by early evening a target scan was performed and 1A
back up to 110 microamps.


On November 24, 2000 the old target ladder which has the T1 protect monitor
with a 5mm gap between the right and left plates was put back in. I stripped
out the data for the last 2 weeks of running with this monitor to see if
the signals read were the same as in the summer or if indeed they were smaller
now.

November 25-30, 2000:
Beam current 120-150 microamps and in pi- mode until Nov 28 pi+ mode.
Signals on left plate -0.5-0 microamps.
Signals on right plate go from 0 to 3.5 microamps, however on Nov. 27 at
6:51 a.m. this signal drops down and fluctuates between -0.5 and 1 microamp
and remains this way.
Dac between -0.1 and 1.2.

Ops Meeting Minutes:
Nov 28 X1 foil exchange because it had shown signs of aging. Front-end
1A tune was improved by reducing the extraction energy and this had positive 
effects downstream. Profile monitor on the ladder not working.
Nov 29 RF problems and could not be turned back on until Nov 30.

December 1-6, 2000:
Beam current 130-140 microamps and in pi+ mode.
Signals on left plate -0.5-0 microamps.
Signals on right plate 0-1.5 microamps.
Dac TW60 between 0.3-0.4, TW61 between 1.1-1.2.

Ops Meeting Minutes:
Dec 1 number of power dips throughout the day which caused main magnet tune to 
wander.
Dec 2 intermittent RF instability prompting lowering 1A current to 130 
microamps.
Dec 3 controls problem that required reboot of all production cluster 
computers. 

Conclusions:
The data logged on the T1 protect monitor during the summer in which the 
left/right plate separation was 5mm was not reproduced between Nov. 24 and 
Dec 6, 2000. For a brief period on Nov 26/27 the signals WERE representative of
what was logged during the summer. The question arises WHAT DO WE DO NOW?
We did not see the increased signals on the new monitor in which the plates 
were closer together and infact, the signals monitored are too small to use 
with the calibration tables derived at from the beam scans of the monitor. In 
this report I do not mention the top/bottom plates as the signals on these 
were well within the range needed to determine a vertical beam position and 
stability.
For completeness it should be noted that the graphite target used in the runs 
did show some breakdown with a piece falling off, although it is not clear at 
this point if this occurred during installation, running or removal of the
target ladder. It also looks like the alignment between the target and the T1 
protect monitor was not optimal.


TAP, December 14, 2000

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