[en] For SBLC, the DESY/THD S-band linear collider study, klystrons with 150 MW rf-pulse power at 50 Hz repetition rate and 3 μs pulse duration are required [1]. This paper will give a short overview of the SBLC parameters and the S-band test linac at DESY. Two different modulator schemes, the conventional line type pulser and the hard tube pulser, will be discussed. After a brief description of the 150 MW S-band klystron the first operating experience with the klystron and a line type pulser at DESY will be presented. (author)

[en] An electron-positron double storage ring for 2x6 A stored beam at 1,8 BeV and 2x0.9 A at 3 BeV has been built and started operating at DESY, the German Electron Synchrotron. The unique double ring structure of 2x288 m length with 2 experimental crossover points allows also particle research with stored electron-electron beams or - after some proposed changes - with electron-proton beams. The main ''vacuum problem'' of high current electron-positron storage rings is the high desorption rate by synchrotron radiation. With full stored beams a pressure in the low 10^-8 Torr scale it is wanted to get a beam life time of a few hours due to ''Bremsstrahlung''. The system has been built as a bakeable UHV-system in order to reach a base pressure of 1.10^-9 Torr or lower without beam. (auth.)

[en] The development of adequate modulators for high peak power klystrons is one of the focus points for linear collider R ampersand D programs. For the DESY/THD S-band linear collider study 150 MW rf-pulse power at 50 Hz repetition rate and 3 μs pulse duration is required [1]. Two different modulator schemes are under investigation. One is the conventional line type pulser, using a pulse forming network and a step up transformer, the other one is a hard tube pulser, using a dc power source at the full klystron voltage and a switch tube. This paper is focused on the modulator development for the S-band Test Linac at DESY. After a short overview over the test linac and a brief description of the 150 MW S-band klystron the circuitry of the line type pulse (LTP) is given. A hard tube pulser (HTP), which switches the high voltage directly from a storage capacitor to the klystron, has been built up at DESY. Circuitry and the results of the commissioning of the switch tube are reported. copyright 1995 American Institute of Physics

[en] Full text: Nitrates have long been the standard therapy for chronic stable angina. The goals of this study were to define the reduction in exercise induced ischaemia among patients treated with isosorbide mononitrate and to examine the issue of tolerance, using quantitative stress myocardial perfusion SPECT (M-SPECT) defect extent and severity as end-point. A total of 20 male patients (mean age: 71.3 years) were studied. Inclusion criteria were chronic stable angina, previously abnormal M-SPECT with demonstrable reversible defect in at least one vascular territory, and no recent Ml or revascularisation. Following baseline M-SPECT off antianginal medication, isosorbide mononitrate was commenced at 6O mg/day for four days, and then at 120 mg/day from the fifth day The second SPECT was performed on Day 5 and the third SPECT after 30-42 days (mean: 35 days) of continuous treatment. Each M-SPECT was processed using a previously validated, commercially available quantitative analysis software package (CEqual) for stress defect reversibility extent (=ischaemic size) and defect severity (=degree of ischaemia) for total left ventricular myocardium and for each coronary vascular territory. The exercise duration and workload were equivalent between all three M-SPECT studies. Total LV ischaemic extent with exercise was reduced (p<0.002) by 9% from baseline to day 5 and by 135 between baseline and day 35 SPECT studies. Ischaemic severity index was also reduced (p<0.0003) by 15% between baseline and day 5 and 14 % between baseline and day 35. Sustained reduction for both ischaemic extent and severity was similarly observed for individual vascular territories with no development of trachyphylaxis over the prescribed treatment period

[en] A two-dimensional laser-wire scanner capable of measuring the transverse charge profiles of an electron (or positron) bunch has been constructed at the PETRA accelerator in DESY. The development of the system is explained in this paper, along with descriptions of its photon detector and laser system. Results of transverse profile scans are presented for both horizontal and vertical directions. The measurement error is 1.3% from a multi-scan measurement in the vertical direction, where single scans can be performed in less than 50 s