We report observations of an intense sub-THz radiation extracted from a ∼3 MeV electron beam with a flat transverse profile propagating between two parallel oversized copper gratings with side openings. Low-loss radiation outcoupling is accomplished using a horn antenna and a miniature permanent magnet separating sub-THz and electron beams. A tabletop experiment utilizes a radio frequency thermionic electron gun delivering a thousand momentum-chirped microbunches per macropulse and an alpha-magnet with a movable beam scraper producing sub-mm microbunches. The radiated energy of tens of microJoules per radio frequency macropulse is demonstrated. The frequency of the radiation peak was generated and tuned across two frequency ranges: (476-584) GHz with 7% instantaneous spectrum bandwidth, and (311-334) GHz with 38% instantaneous bandwidth. This prototype setup features a robust compact source of variable frequency, narrow bandwidth sub-THz pulses.

A new digital signal processor (DSP)-based data acquisition system has been designed and installed at the Advanced Photon Source. This system uses a commercial VME-based DSP card to acquire and process x-ray blade signals to determine x-ray beam position for both bending magnet and insertion device beamlines. The system also acquires and processes position data from the narrowband rf BPMs that straddle each insertion device. It is integrated within the storage-ring fast-feedback system and provides filtered data to both the feedback system and the EPICS control system. Features of the system, including analog and digital signal processing, are discussed.

Abstract. At the Advanced Photon Source (AI%) storage ring, the X-ray beam position monitors (X-BPMS) measure accurate photon position down to the subrnicron level. This level of stable measurement has been possible due to 1) superior thermal insulation and vibration damping of the X-ray BPM support structure [1], 2) minimal dependence on the bunch pattern and intensity variations, and 3) use of uhrastable preamplifiers and processing electronics. A new X-BPM interface is under development and will be discussed here. This interface will be integrated into the existing rf-based orbit feedback systems. To study preliminary results, an experimental X-BPM orbit feedback set-up was developed and implemented in one of &e bending magnet beamlines. The results from this set-up are encouraging. For an operational fill, a typical orbit drift of 30 microns (at X-ray BPMs) has been reduced to less than 5 microns. The fill-to-fill photon orbit reproducibility has been improved from 75 microns to less than 10 microns.-

No abstract

No abstract