ISA meeting

Week 8, February 20, 2001.

Status of the ring: The ring has been running well, with currents around 200 mA and good lifetimes. We have, however, had a few problems during the week. Early Sunday morning, we had a leak in the dipole current supply causing a beam loss, and the problem could not be fixed until Monday morning. Besides that, we have had a few cases of beam losses of unknown cause. This morning we went back to the acceleration ramps we used in the beginning of the run, to see if the modifications we made a few weeks ago might be responsible for the problems.
Yesterday, we lowered the level of vertical excitation from -6 to -9 dBm, in order to provide a vertically smaller beam, which could result in improved resolution and perhaps improved spatial stability, but of course at the same time in a slightly reduced lifetime.
We will make one injection daily from now on, unless the users request an afternoon injection. Just contact JSN (4822) or NH (3707).

The SX 700 monochromator is having serious problems, because a power amplifier for the mirror motor is out of order. The card cannot be repaired here, and since it is more than 10 years old, it is not simple to find a replacement. Until the card is fixed or replaced, the SX 700 is out of operation.

The UV1 monochromator is running well, and SVH reports that following a careful line-up, spectra with a good resolution have been recorded. The hardware for the sample chamber will be ready later this week.

ELISA has started to run Fullerenes. This will continue for the next 3 weeks.

A NorFA Research Training Course on Application of X-ray Synchrotron Radiation in Chemistry, Biology and Physics will be held at Sandbjerg June 24 to July 1. More information on http://www.chem.au.dk/sandsync .

A study circle on biomolecules is held every Tuesday in 525-323. The oxygen-transporting proteins myoglobin and hemoglobin are the topic for the lecture today (at 14:15). Keywords: the heme group, allosteric interactions, the Bohr effect, protein dynamics (monitored by vibrational spectroscopy).
If you want further information, or get on the mailing list, please contact Steen Brøndsted Nielsen ( ).



20/2 2001 / +