ISA meeting

Week 42, Oct. 14, 1997.

Status of the ring: The electron run ended Monday morning at 2h00. In the last week, we had 160-180 mA and sometimes lifetimes in excess of 20 hours. We will acquire a rf-generator with phase-modulation to be used permanently as the rf-source.
The parasitic electron extraction was used by Jens Jørgen Gårdhøje & Co. from the Bohr institute. They performed their tests more or less as planned, although they were bothered by pick-up of rf-noise from the ring. They are planning new tests next year, and we will have to prepare these in advance.
In this connection, we have asked DANFYSIK for an offer for a spare septum coil. The reason is that there is a risk to burn the coil during the high-current operation necessary for the extraction. Furthermore, the coil is believed to have a short (!?) lifetime due to the very large water-flow.

The vacuum interlock system is being modified by Tonny and Johnny. The main changes concern the possibility of easy bake-out of the undulator chamber without the surrounding parts of the ring.

The changes of the ring in this shut-down period is progressing according to schedule. The new plungers for the electron cavity are almost finished; only the silver-plating is pending.

The SGM/SCIENTA beamline has shown an unprecedented resolution, at least in Århus. The resolution is a significant factor better than in the SX-700, enabling a clear observation of the splitting between the surface and bulk 2p photoelectrons from Al. The energy separation between these is around 100 meV. Also the flux is much larger than at the SX-700, reducing the data-taking by more than a factor of ten. The broken motor is still being repaired by Micro-Controle. Søren Hoffmann and Kåre Iversen will look into the possibilities of using the same motors as those to be acquired for the new SGM-2.

The post-focusing mirrors on the undulator beamline are functioning well. There is one uncertainty regarding this beamline. It seems that the maximum photon energies, for a given harmonic, does not correspond to maximum flux, for a scan in horizontal angle. This is the case in the vertical direction, as expected.

SPM