CAT Chat Minutes

January 7, 2000

Information and Follow-up Items

1. Will the liquid nitrogen distribution system A Module be turned back on by the end of the day once the subcooler is installed?

The lines are currently being cooled down so the system should be available by the end of the day. Bob Ferry will verify the status and let you know either way.

2. When can we begin to utilize the liquid nitrogen in the distribution system?

The system can be used once the module has been accepted from the installer, and liquid has reached your tap location.

3. A hardware failure occurred on December 22, which caused beam instabilities at our beamlines. The problem required the stored beam to be dumped. Since no other sectors were impacted, this was not done and our user lost beamtime. What’s the APS policy in this situation?

In this particular situation, shortly after determining the cause, a workaround solution was implemented which did not require the beam to be dumped. All three of the affected beamlines were queried as to the fix, and all reported that the corrected condition was acceptable. In general, the APS is establishing a clear definition of the operating parameter set, including beam stability and emittance criteria with an operating range. Once these operating limits are defined, the beam will be dumped and the problem fixed whenever operation exceeds these limits. Minor problems, that do not exceed the limits and cannot be fixed during stored beam without affecting the operating conditions, will be addressed at the next refill time or during the next studies period.

4. Why was the Special Operating Mode, (SOM) steering different and not as stable for this past end of the run?

There were significantly more problems with power supply stability during that period of time. This would have been the primary cause. In addition, since the filling pattern for the SOM is relatively new, we have not had the operational experience with this pattern to refine all of the position feedback algorithms to the same level as with the singlet fill mode. Since the changes that you see are near the sensitivity limits of the rf BPMs, your input is important in identifying and quantifying the correction terms. We ask that you inform your floor coordinator when unexpected beam motion is detected so that we can have the accelerator physicists address the problem quickly.

5. On Monday, January 3, an employee slipped on a patch of ice in the 433 parking lot. Icing is also a problem in the 434 parking areas. Can we get these areas salted early when bad weather occurs?

PFS has been contacted again regarding getting out to salt earlier. We are also looking at how to correct the drainage issues in both of these parking areas.

User Operations

The user run will begin at 0800 hours, Wednesday, January 19, with singlets and two fills per day. We are still planning on making some minor timing adjustments (of the order of 10 nsec) to the singlet fill pattern to make the fill pattern more periodic.

Top-up studies are set-aside for a two 24-hour period of machine studies during the next run. These periods are as follows: Monday, February 28 at 0800 through Tuesday, February 29 at 0800 and Monday, March 13 at 0800 through Tuesday, March 14 at 0800.

General Information

A meeting is scheduled next Tuesday, January 11 with the CAT computer system representatives. One of the topics of discussion will be to present and discuss computer security issues. The discussion will include the planned requirements and anticipated impacts.

Liquid Nitrogen Update A total of three subcoolers have been returned for installation. The A module subcooler will be installed today, Friday January 7. The B module (Sectors 10-17) subcooler will be installed also and can be turned on by Tuesday, January 11. The C module (Sectors 18-20) will be installed Tuesday night and turned on by Friday, January 14. The last subcooler will be repaired and returned in a week and will go into the D module supplying Sector 33. By the end of next week, all modules should be done except for D.