Reliability and Performanceof the Diagnostics

Alan Fisher

2007-11-16

HER SLM

Uli’s talk showed several inconsistencies in comparing the measured HER and LER sizes to luminosity.

I’ve made no changes to the light monitors during the down. Streak camera

No HER light to Building 675 for streak camera measurements during the test of the 90-degree lattice.

Misaligned mirror was found and readjusted in the summer. We then took streak data with the old lattice, and so we should be

ready to compare lattices when we start up. Wide HER x

May be deformation of the primary mirror Cannot realistically be addressed in the time remaining.

However, last winter I inserted a movable mask on the optical table at an image plane of this mirror, in order to block light from portions of its surface. This made the image cleaner, but not narrower.

LER SLM and SXM

SLM: Gets light from the coupled region near the IP, which broadens the y size.

SXM Usually shows a rotated ellipse at low current, suggesting coupling This ellipse rotates over time with tuning and over the course of a fill. Using the y projection of this rotated ellipse rather than the minor axis

size (both available from the software) will give a broader vertical size. At high current the ellipse becomes nearly circular, with any of the

four pinhole sizes. Scintillator

Beginning to show fogging. Not yet bad, but I have been looking for a different material and just received a quote.

I can find no other reasons to doubt this measurement of y blow-up in collision.

I will recheck the software for the x/y and major/minor fit.

Translating to the IP

I have on-line software using Yun-Hai’s model (but not including dynamic beta) to move the sizes at the light monitors to the IP.

The LER does not work at all with one monitor, but requires an SVD solution combining data from both the SLM and SXM.

There are still questions about the resulting values.

BCM and BIC

Minor improvements to the new hardware have been completed.

Full system is now properly set up in the temperature-controlled cabinet.

UPS units added for backup power. The firmware and software versions used in the

summer worked, but we are now testing improvements to both, with the expectation that the changes will be ready for use at startup. Otherwise, we can revert to the code used in the summer.

Tune

There have been no changes to the HER and LER x and y tunes.

The spectrum analyzer for both rings’ synchrotron tunes was sent out for repair early in the down, because it reported a calibration failure due to the Channel-2 pads. This is still out, since the repair got more involved than initially expected. I am trying to get the unit back by the start of the run.