• A.S. Aryshev, N. Terunuma, J. Urakawa
  KEK, Ibaraki
• S.T. Boogert, V. Karataev
  JAI, Egham, Surrey
• D.F. Howell
  OXFORDphysics, Oxford, Oxon

Optical Transition Radiation (OTR) appearing when a charged particle crosses a boundary between two media with different dielectric properties has widely been used as a tool for transverse profile measurements of charged particle beams in various facilities worldwide. The resolution of the conventional monitors is defined by so-called Point Spread Function (PSF) dimension - the source distribution generated by a single electron and projected by an optical system onto a screen. In our experiment we managed to create a system which can practically measure the PSF distribution. We demonstrated that is it is non-uniform. In this paper we represent the development of a novel sub-micrometer electron beam profile monitor based on the measurements of the PSF structure. The visibility of the structure is sensitive to micrometer electron beam dimensions. In this report we shall represent the recent experimental results. The future plans on the optimization of the monitor will also be presented.

• A.S. Aryshev, S. Araki, M.K. Fukuda, J. Urakawa
  KEK, Ibaraki
• V. Karataev
  JAI, Egham, Surrey
• G.A. Naumenko
  INPR, Tomsk
• A. Potylitsyn, L.G. Sukhikh, D. Verigin
  TPU, Tomsk
• K. Sakaue
  RISE, Tokyo

High-brightness and reliable sources in the VUV and the soft X-ray region may be used for numerous applications in such areas as medicine, biology, biochemistry, material science, etc. 4th generation light sources based on X-ray free electron lasers are being built in a few world's leading laboratories. However, those installations are very expensive and the access to wider community is very limited. We propose a new approach to produce the intense beams of X-rays in the range of less than 500 eV based on compact electron accelerator. An ultimate goal of the project is to create a compact soft X-ray source based on Thomson scattering of Coherent Diffraction Radiation (CDR) using a small accelerator machine. CDR is generated when a charged particle moves in the vicinity of an obstacle. The radiation is coherent when its wavelength is comparable to or longer than the bunch length. The CDR waves will be generated in an opened resonator formed by two mirrors. In this report we represent the status of the experiment. The pilot experimental results and general hardware design will be demonstrated.

• S.T. Boogert, G.E. Boorman, C. Swinson
  JAI, Oxford
• R. Ainsworth, S. Molloy
  Royal Holloway, University of London, Surrey
• A.S. Aryshev, Y. Honda, T. Tauchi, N. Terunuma, J. Urakawa
  KEK, Ibaraki
• J.C. Frisch, J. May, D.J. McCormick, J. Nelson, T.J. Smith, G.R. White, M. Woodley
  SLAC, Menlo Park, California
• A. Heo, E.-S. Kim, H.-S. Kim, Y.I. Kim
  Kyungpook National University, Daegu
• A. Lyapin
  UCL, London
• H.K. Park
  KNU, Deagu
• M.C. Ross
  Fermilab, Batavia
• S. Shin
  PLS, Pohang

The Accelerator Test Facility 2 (ATF2) in KEK, Japan, is a prototype scaled demonstrator system for the final focus required for a lepton linear collider. The ATF2 beam-line is instrumented with a total of 38 C and S band resonant cavity beam position monitors (BPM) with associated mixer electronics and digitizers. The current status of the BPM system is described, with a focus on operational techniques and performance.

• M.K. Fukuda, S. Araki, A.S. Aryshev, Y. Honda, N. Terunuma, J. Urakawa
  KEK, Ibaraki
• A. Deshpande
  Sokendai, Ibaraki
• K. Sakaue, M. Washio
  RISE, Tokyo
• N. Sasao
  Okayama University, Okayama

We have developed a compact X-ray source based on inverse Compton scattering of an electron beam and a laser pulse, which is stacked in an optical super-cavity, at LUCX accelerator in KEK. The accelerator consists of a photo-cathode rf-gun and an S-band accelerating tube and produces the multi-bunch electron beam with 100 bunches, 0.5nC bunch charge and 40MeV beam energy. It is planned to upgrade the accelerator and the super-cavity in order to increase the number of X-rays. A new RF gun with high mode separation and high Q value and a new klystron for the gun will be installed to provide good compensation with a high-intensity multi-bunch electron beam. A new optical super-cavity consisting of 4 mirrors is also being developed to increase the stacking power in the cavity and to reduce the laser size at the focal point. The first targets are to produce a multi-bunch electron beam with 1000 bunches, 0.5 nC bunch charge and 5 MeV beam energy in low energy mode and 100bunches, 2 nC and 40 MeV in high energy mode to generate X-rays by inverse Compton scattering. In this paper, the status and future plan of the accelerator will be reported.

• M.D. Hildreth
  University of Notre Dame, Notre Dame
• A.S. Aryshev
  Royal Holloway, University of London, Surrey
• S.T. Boogert
  JAI, Egham, Surrey
• Y. Honda, T. Tauchi, N. Terunuma
  KEK, Ibaraki
• G.R. White
  SLAC, Menlo Park, California

The demonstration of the stability of the position of the focused beam is a primary goal of the ATF2 project. We have installed a laser interferometer system that will eventually correct the measurement of high-precision Beam Position Monitors used in the ATF2 Final Focus Steering Feedback for mechanical motion or vibrations. Here, we describe the installed system and present preliminary data on the short- and long-term mechanical stability of the BPM system.