ESRF

The facility now includes 26 operational beamlines, which will increase to 39 by the end of Phase II (end '98). The machine reliability is very good, with 95 % average up-time in '96 and mean time between failures of 41 hours. Reliability has been increased significantly by the non-interruptable power supply, which avoided more than 220 electrical fluctuations. Only occasional direct hits by lightening now cause machine stoppage. Operation of a second klystron has also reduced downtime due to the r.f. system. Seven different filling modes are currently used. The lifetime increase in 2/3 filling compared to 1/3 filling clearly shows that the Touschek effect also plays a role with high energy machines. Machine developments in '96 have included new lattice functions with low vertical beta in all straight sections, reduction of the coupling to 1 %, development of 8 mm internal/10 mm external copper-plated vacuum vessels, and the test of a Spring-8 in-vacuum undulator. The first new filters have also been installed on the beam lines to allow the use of three undulator sections with 200 mA stored current. The goals for 1997 are 5400 hours for user operation (with about 18% of the total time dedicated to start-up and machine studies), commissioning of a third r.f. plant and installation of the new low gap ID chambers. Studies will also be made for a further reduction in the emittance (3 nmrad) and coupling (0.3 %).

MAX II

The commissioning phase for MAX II has now ended and the operational phase is beginning. Both the design energy and current have been reached. MAX I is used as the injector providing 30 mA/shot, once per minute, allowing a re-filling time of 10-20 minutes. The capture efficiency between the two machines is about 40 %. MAX II has non-zero dispersion in the straights. The sextupole fields for chromaticity compensation are generated in the quadrupoles, with backleg coils for adjustment. No major problems have been observed due to the integrated sextupole fields; two different optics have been tried, although not greatly different in sextupole strength. SIP's in the bending magnet chambers are used for pumping and titanium sublimation pumps are used once per week. The lifetime is lower than foreseen (0.7 Ah, instead of 2 Ah) and is probably due to the lower coupling than expected (1 rather than 10%). The energy acceptance is 1.5%. There is little demand for short bunch lengths and a greater demand for low emittance and so rather than acting on the coupling to increase the lifetime a Landau cavity, working at the third harmonic 1.5 GHz, will be installed to increase the bunch length. At the same time it will combat multi-bunch instabilities by providing synchrotron tune spread. No bunch length measurements have yet been performed. The first phase of beamline construction foresees the installation of four beamlines for insertion devices and two from bending magnets.

DORIS III

The last major rebuilding of the facility has been to remove the vertical bending magnets in order to eliminate the vertical dispersion, as well as to save money on electrical power. A new ID vacuum chamber has been installed with 11 mm internal and 15 mm external dimension, consisting of copper halves soldered together with distributed NEG pumping. Nine photon beam position control loops are in operation using information from photon beam monitors. Closed orbit movements have been traced to the asymmetric heating of the dipole chambers at the ID outlet, causing movement of the adjacent quadrupole chamber, and also of the quadrupoles themselves. Six new chambers will therefore be installed in mid '97 with additional cooling on the inner side of the chamber; at the same time the fixing of the quadrupole vessels to the magnets will be removed. Overheating of the vertical multibunch feedback limits the current that can be obtained in the 5-bunch mode; to solve the problem a new design with water cooled ferrite will be installed during the next summer shutdown.

DELTA

First stored beam at 1 GeV was achieved in DELTA on the 16th August, followed by accumulation of 10 mA (limited by vacuum effects) in October. Radiation from the FELICITA 1 undulator has been observed and also transported out of the shielding wall. The ring is presently shutdown for bake-out and NEG activation. The linac is operating at 70 MeV due to an r.f. power limitation. The booster has recently been improved to increase the rep. rate (10 cycles/minute) and reduce beam losses. Stray fields from the booster which affect the storage ring have been noted. The plans for '97 are to commission the 4-bunch FEL mode as well as the 1.5 GeV SR user mode, to install the optical cavity and obtain lasing.

Kurchatov Synchrotron Radiation Source

The six-fold symmetric storage ring, SIBERIA II, achieved full energy (2.5 GeV) and 10 mA in July '96. By the end of the year 100 mA should be achieved, as well as the first experiments performed on the first 3 VUV beamlines. The chamber is made of aluminium with some parts in stainless steel. An 180 MHz r.f. system has been adopted. SIBERIA I is used as injector (450 MeV) with a cycling time of 30 seconds. A large number of beamlines are under construction. A collaboration for LIGA technology is in progress with the university of Mainz. In 1997 it is hoped to commence regular X-ray experiments with 300 mA beam current.

ELETTRA

ELETTRA is currently operating for a total of about 6100 h/yr. with 5000 h for users, and with an average up-time of about 92 %. The major source of down-time is due to storms, predominantly in the summer months. Injection is performed once per day at 1 GeV, followed by ramping to 2 GeV, with an initial current of 250 mA. The total time for a re-injection is around 20 minutes. There are no requests at present to operate in single bunch mode. Five IDs are operational as well as one bending magnet beamline. Higher order modes in the r.f. cavities are cured by a combination of cavity temperature adjustment and HOM frequency shifters. Some residual longitudinal excitation is accepted in order to increase the beam lifetime. Developments in progress include substitution of BPM gaskets to permit higher beam currents, installation of adjustable HOM frequency shifters in all 4 cavities, development of a transverse coupled bunch feedback system and a global orbit feedback system, and increased automation. An electromagnetic elliptical wiggler has been designed and will be installed in 1997. Lower gap ID vessels are also under study.

prepared by C.J. Bocchetta and R.P. Walker