11/24/03 Beam Studies

Owl (0:00 - 8:00)

Studies conducted:
- IA scan to test for reproducibility. - PZT scan to check for orthogonality, and subsequent scans with tweaking of skew quad MQS0I07 and MQS0L01.
Results:
- It is seen that the IA reproduces the charge asymmetry. It has a large range (~1000ppm/V) with only a small zero-offset.
- PZT scan shows a gradual orthogonality breakdown starting at BPM0I02A to BPM0L02. Skew quad MQS0L01 does not seem to fix things, although it is possible, that I did not try out a large enough range for that quad. MQS0I07 does seem to correct the orthogonality between BPM0I05 and BPM0L02. One can see the difference in orthogonality from the below two plots:
Before MQS0I07 correction
Before MQS0I07 correction
This shows promise that the orthogonality maybe fixed at BPM0L02. We cannot infer from the above plot whether there is orthogonality breakdown downstream of this BPM (but I believe it is highly likely). Once we can take HallC data, we will see if we can tweak this skew quad to fix the orthogonality in the Hall.

Day (8:00 - 16:00)

- The Day shift is devoted to beamstudies done by the Accelerator group (no shifters in HallC).


Swing (16:00 - 24:00) and 11/25/03 Owl (00:00 - 08:00)

- No beam in the Hall at the beginning of shift.
- 6:30 - Access was taken into the Hall. Julie went to check one of the silicon cookies in the PMTs to check for degredation. Other than that, the entire swing shift spent waiting for beam.
- 00:30 - 40uA of G0 beam came to hall. Jianglai and Jeff see that BCM1 and 2 in the hall are not being read in EPIC or g0analysis. Furthermore, the UNSER seems to read 100uA. I'll speak with Dave Mack about this in the morning.
- 2 hours allocated for BPM calibration for the HallC BPMs. The beam current was read out from the ACC general tools screen. The EPICS variable name is IBCxxxxCRCUR4, but nobody seems to know where this is located. MCC OPS crew tells me it should be close to the Hall, but they don't have a definite answer to exactly where it is.
- 03:00 - BPM calibration went well. All BPMs except C20 seemed to show a nice wire-response to beam current. The problem with this BPM is that at 40uA, its gain is a factor of 2 smaller compared to all other BPMs. The new pedestals will be incorporated into g0analysis (the perl script that supposedly automates this is not working at the moment).
- A PZT scan was done to make sure the BPMs do see beam motion at these BPMs. There was a problem with this PZT scan in that the beam tripped half way through it, and ACC had some trouble returning beam. Injector phasespace from this PZT scan looks odd especially after the beam trip. I've been told the orbit lock in the injector could automatically change corrector settings after a trip.
- 04:30 - ACC sending pulsed beam to Hall to do beam profile measurements.
- 05:30 - ACC wants to send unrastered pulsed G0 beam to HallC (limit is 2uA). They then ask to send 2uA pulsed diode beam to HallC to test out a new software. They say the intensity is larger for the diode beam. Although I can't imagine the 2uA pulsed diode punching a hole or burning the exit window, we agreed to be prudent especially since I'm not sure how much the exit window can take. They wanted a large enough signal so the superharps can see the beam, but this test was postponed to a later date (perhaps when the target is in).

Future Schedules

- Swing shift of 11/25/03 will be devoted to:
1. Coilpulsing checkout.
2. Energy modulation checkout.
3. Halo monitor checkout (as far as we can go on Sarah's testplan).
4. Simultaneously with the above two testplans, John Musson as well as the CMU crew can check out the YO if they believe it to be useful. This can be done as long as the check is not invasive.

- Owl shift of 11/26/03 will be devoted to:
1. G0 parity studies including PZT/IA/RHWP scans. This is expected to be the first measurement of the adiabatic damping factor.
2. 30Hz ACC FOPT measurements.