• A.P.Potylitsyn, L.G.Sukhikh, A.V.Kostousov
  Tomsk Polytechnic University, Tomsk, Russia

• J.Urakawa, A.Aryshev
  KEK, Tsukuba, Japan

• S. Boogert, P.V.Karataev
  John Adams Institute at RHUL UK

The processes of generation of coherent diffraction radiation (CDR) by a short electron bunch of 45-MeV S-band electron accelerator and it’s Thomson scattering on one of the subsequent bunches have been simulated. Backward CDR is emitted when electron bunch with population and length passes in a vicinity of a conducting target along the direction of specular reflection. In the wavelength region all electrons in a bunch emit coherently and CDR intensity becomes proportional to the square of a bunch population. For a target with inclined angle 45^o CDR beam may be extracted from the accelerator chamber at right angle to an electron beam. For this geometry we calculated CDR spectral-angular distributions from concave targets with different profiles which allow to focus radiation at different distances. If the direction of specular reflection coincides with electron path it is possible to use a concave target with a focal distance providing the maximal overlapping of CDR pulse and a subsequent electron bunch. In this case one may obtain hard radiation in forward direction for the photon energy range as a result of Thomson scattering. The yield of hard photons is proportional to [1]. For the following accelerator parameters [2]: Beam energy - 45 MeV; Charge/bunch - 500 pC; Beam emittance - 3 mm mrad; Bunch length - 0.3 mm. we estimated the efficiency of considered schemes for obtaining of radiation and soft X-ray radiation ( eV) with duration ps.

REFERENCES [1] A.P. Potylitsyn, Physical Review E, vol. 60, 1999, p. 2272. [2] H. Koichiro et al., Nucl.Instrum. and Methods A, 2006 (to be published).

147

• A.S.Gogolev, A.P.Potylitsyn
  Tomsk Polytechnic University, Tomsk, Russia

• A.M.Taratin
  JINR Russia

The accelerated beams extraction is one of the important problems of modern facilities, such as J-PARC or Tevatron. One of an efficient approach is the beam extraction with using bent crystal deflectors. The on-line control of the quality of crystal structure of deflector becomes necessary, when crystal deflector is used to extraction of intense proton or ion beams. For example, intensity of proton beam at accelerator J-PARC is ~ 3*10¹⁴ per spill. Investigation the possible radiation damage of usually used silicon deflectors is the open question for such beams. In this work, the monitoring of crystal deflectors quality based on registration of parametric x-ray radiation (PXR) is proposed. Proposed method gives a possibility to control a uniformity of deflector bending by measuring a PRX line width and allows to estimate a damage of deflector crystal structure under intense beam.

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• Y.N.Adischev, А.V.Vukolov, A.P.Potylitsyn
  Tomsk Polytechnik University, Tomsk, Russia

• К.V.Afanasiev
  High-current electronics institute SB RAS, Tomsk, Russia

The dose field map of the nanosecond accelerator on the basis of the vacuum diode supplied by the high-voltage nanosecond generator with the coaxial forming line combined with the transformer has been measured. The high-current electric beam created by the “blade” metallodielectric cathode has been measured too. The accelerated electrons at the collector from the stainless steel 1mm in thickness have generated the bremsstrahlung radiation. The dose field map has been taken by the dosimeter ДКД - 01 on the basis of the diamond detector in the median acceleration plane. The bremsstrahlung radiation beam divergence has left 62°. It has been shown that the maximum dose is 16 cGrey/s at the distance of 10 cm from the collector, then it falls down proportionally to the square of distance to the level less than 0.1 cGrey/s at the distance of 1 m.

342

• S.A.Gorokhov, M.K.Polkovnikov, Y.V.Rodnov, A.P.Vorobiev, R.E. Rydenko
  Institute for High Energy Physics, Protvino, Russia

• V.V.Kashkovskiy, A.P.Potylitsyn, A.R.Wagner
  Tomsk Polytechnic University, Tomsk, Russia

• G.I. Ayzenshtat, O.P. Tolbanov
  Research Institute for Semiconductor Devices, Tomsk, Russia

The problem of creation of the most effective high intensity x-ray radiation sources for a digital diagnostics in medicine and other fields remains actual till now. In the work, experimental results on design of digital radiographic set-up based on the bremsstrahlung source of betatron MB-6 are presented. Betatron has following parameters: electron energy is 6 MeV, beam current is 100 nA, frequency is 50 Hz, dose rate on bunch axis is 35mG/minute at distance 1m, thickness of tantalum target is 0.6 mm. The set of 640 gallium arsenide detectors with size 0.2х0.2х2 mm³ with sensitivity in photon energy range up to 200 keV was used. The digital images of investigated object have been received by scanning technique. The use of thin betatron target allows avoiding self-absorption of bremsstrahlung photons in target. It will lead to increase in intensity of registered radiation by the detector and reduce an exposition time to achieve high level image quality and pattern contrast.

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