CAT Chat Minutes

March 14, 1997

 

Issues that require action and/or follow-up
1. How do I get a copy of the draft long-term schedule?

That schedule was shown to the CAT Directors at the Research Directorate Meeting so that everyone is aware of the intention of the APS to provide users with as much user operations time as possible. Before early April, the long-term schedule will be finalized and published on the Web.

2. Do the TVs that are being installed have remotes?

Yes, the FCs have the remotes, but the TVs are meant to stay on one channel, because only one channel has the information on storage ring performance. If you need to be able to get additional CAT-owned TVs wired into your stations or to the LOM closet, please see M. Ramanathan or B. Ferry.

3. Will there be anything else available on the TVs that is not available on the Web?

Not at this time. In the future, information on beam profile, etc., will become available on other channels.

4. It is very noisy near the FOE in Sector 13. What can be done?

It may be that we need to look at your area to determine the source of the noise.

5. During the last run, I had large variations in the intensity of the beam. Is this same information as evaluated by APS available somewhere else? Do you have a diagnostic station set up to follow this variation?

No, the information at this time is not available anywhere else. We will have Sector 35-ID beamline on-line soon to take this information, but this beamline is only now being commissioned. If you find large variations, please pass this information along to the FCs. During the next run, you will see the image of the beam observed in 35-BM available on a TV channel. We will also implement a system of real-time XBPM that will give you an analog signal during the next 6-8 months.

6. The energy at which I find the maximum flux from the ID is 200 eV less than the energy displayed in the ID control window. Why?

The displayed first harmonic energy is calculated from the measured effective magnetic field. It is a simple calculation that neglects the effects of finite particle beam emittance, particle beam energy spread, and the finite size of the user's pinhole. These effects will reduce the energy of the observed photon beam as compared to the calculation. This effect is gap dependent. We are calculating these effects in detail and will include them in the displayed calculated energy in the future.

Your monochromator should give you the best energy information. Also realize that, based on the size of the pin-hole(s), the harmonics energies may shift. Hence, for the immediate future, use the look-up table only as guidance.

Information
The next Beamline Operations Schedule for the April run is now on the Web. The shielding verification schedule is also there.

If you are preparing for shielding verification of a monochromatic station , please give us 48 hours notice of when the station will be ready for beam, so that we can include your station on the schedule. We need 48 hours to set up for shielding verification.

We had some leaks on the 14-ID front end that we will fix during the current maintenance period. Before the next operations period, we will be ready to integrate Sectors 6 & 15 BM FEs. We have pulled four IDs for rearranging the location of the hard stops on Sectors 8, 10, 12 and 2.