Hideki Aoyagi

Performance of a Highly Stabilized and High-resolution Beamline BL17SU for Advanced Soft X-ray Spectroscopy at SPring-8

A new soft x‐ray beamline BL17SU (RIKEN) has been constructed at SPring‐8. The beamline consists of two branches with each varied‐line‐spacing‐plane‐grating‐monochromator. Both monochromators perform high energy resolution (E/ΔE > 10,000) between 0.2 and 1 keV. One of the monochromator achieves high energy stability of 10 meV over a period of half a day.

RISING beamline (BL28XU) for rechargeable battery analysis

The BL28XU beamline, dedicated to rechargeable battery analysis, is described.

Present Status and Performance of SPring-8 Front Ends

SPring-8 front ends have a novel structure which makes it easy to rearrange them and exchange the components. The structure has a common support for all the components except X-ray beam-position monitors and lead collimators. The alignment of the common support as well as the components was carried out with an accuracy of 0.25 mm in the vertical and horizontal directions. Replaceable pumping systems have also been placed on the common support and have achieved a vacuum of 2 x 10(-8) Pa at the upstream part of the front ends without synchrotron radiation. During the commissioning with synchrotron radiation, the pumping systems displayed good pumping-down characteristics. Commissioning has been successfully performed for four standard in-vacuum X-ray undulators and three bending-magnet-beamline front ends up to July 1997. Measurements of temperature rise show that absorber, pre-slits and XY slits can handle the anticipated maximum heat load at a ring current of 100 mA.

Diamond beam-position monitor for undulator radiation and tests at the Tristan Super Light Facility.

A photon beam-position monitor using a diamond foil as a position-sensitive device has been developed for use on insertion-device beamlines of third-generation synchrotron radiation facilities such as SPring-8, and was tested on the undulator beamline of the Tristan Super Light Facility at KEK. The beam test results show that the diamond monitor can be operated in a photoconductive mode like a semiconductor detector. It has a linear working range of about +/-1 mm and a position sensitivity of less than 3 mum. The stability of the monitor was confirmed by continuous operation under low photon beam intensity conditions.

Electronics for SPring-8 X-ray beam monitors

A sensitive current-measuring system is required to construct a highly sensitive X-ray beam-position monitor (XBPM). A current-voltage converter (I/V) which can measure currents between 0.1 nA and 10 mA was designed, and the signal processing system of the XBPM was constucted using this I/V. This system was used in beamline commissioning. Beam-position data standard deviations of sigma approximately 3 micro m for the bending-magnet beamline, and sigma(x) approximately 3 micro m and sigma(y) approximately 1 micro m for the insertion-device beamline were obtained during the beamline commissioning.

Performance of Frontend Pulse‐by‐Pulse SR Beam Monitor with Microstripline Structure

We have developed a frontend pulse‐by‐pulse synchrotron radiation (SR) beam monitor with microstripline structure, which is operated in photoemission mode. This monitor is composed of a detector head with a microstripline having the band‐width of several GHz, an electrode for applying high voltage and a mask. This monitor can be used for monitoring not only the pulse‐by‐pulse photon beam position, but also the SR pulse intensity and the pulse timing. Beam tests of this monitor have been carried out and feasibilities have been demonstrated.

RF Properties of Coaxial Feed‐through Connectors for Design of a Frontend Pulse‐by‐Pulse SR Beam Monitor

Radio frequency (RF) properties of coaxial feed‐through connectors that are designed for a frontend pulse‐by‐pulse synchrotron radiation (SR) beam monitor are described in this paper. We have designed and fabricated a small detector head operated in photoemission mode. This detector is directory connected to a SMA feed‐through connector to have fast response time. Using this detector we successfully observed an isolated pulse of monochromatic beam. In order to improve RF properties of this detector, we have carried out simulation study and measurements of newly designed prototypes.

New configuration of photoconductive‐type diamond detector head for X‐ray beam position monitors

We designed and fabricated new diamond detector head for an X‐ray beam position monitor (XBPM). This monitor operates in photoconductive mode, and is shaped into a blade in order to reduce heat load. A pair of aluminum electrodes is formed on both sides of the diamond blade. The profile of the detection efficiency inside the diamond detector head was measured. The signal current is generated only between the pair of electrodes. The bias voltage dependence of signal current along a section of the detector head is also measured. The results show that the detector head operates in photoconductive mode. We demonstrated that this detector head is feasible for the XBPM.

Alignment of front end components at SPring-8

We review the alignment of front‐end components at SPring‐8. The front end is the part of a photon beamline, which is located between the photon beam port of the storage ring and the beryllium (Be) window assembly. The photon beam from a light source is guided to the optics hutch through the front end. We have constructed 43 front ends with the following design concepts; (1) use of a single common base (a pair of parallel I‐beams), (2) employment of standardizing approach, and (3) independent units of pumping system. The alignment work has been performed in the procedure of inspecting the datum points on the floor, installation of the common base, and installation and alignment of components on the common base. This work has been successfully carried out with sufficient results. The alignment error of I‐beams is about 50 micron in standard deviation. The components return to their original positions even if some displacements occur during baking procedures. We have had no serious troubles about the alignm...

High‐speed and simultaneous photon beam diagnostic system using optical cables at SPring‐8

We have developed a high‐speed and simultaneous photon beam diagnostic system using optical cables at SPring‐8. The system is composed of blade type X‐ray beam position monitors (XBPM) in front ends, optical cables spread over the experimental hall and multi A/D converters at the photon beam diagnostic station. Analog data of the beam positions are transferred through the optical cables. The multi A/D converter allows us to browse and process the data from the main control room in real time. The features of the system are the wide band‐width, the ability of full‐time observation with XBPMs and the compatibility to the monitoring system of electron beam position monitors in the storage ring. The system has been routinely used for high‐speed and simultaneous measurements of photon beam and electron beam.