CERN Accelerating science

Article
Report number	SLAC-PUB-11680
Title	The Possibility of Noninvasive Micron High Energy Electron Beam Size Measurement Using Diffraction Radiation
Author(s)	Naumenko, Gennady ; Araki, Sakae ; Aryshev, Alexander ; Cline, David B ; Fukui, Yasuo ; Hamatsu, Ryosuke ; Hayano, Hitoshi ; Karataev, Pavel ; Muto, Toshiya ; Potylitsyn, Alexander ; Ross, Marc ; Urakawa, Junji
Affiliation	(KEK, Ibaraki) ; (SLAC) ; (TMU, Hatioji-shi, Tokyo) ; (Tomsk Polytechnic University, Tomsk) ; (UCLA, Los Angeles, California)
Publication	2005
Imprint	May 2005
Number of pages	3
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.404
Subject category	Accelerators and Storage Rings
Abstract	During the last years a noninvasive method for beam size measurement based on the optical diffraction radiation (ODR) has been in progress (P. Karataev, et al., Physical Review Letters 93, 244802 (2004). However this technique encounters with hard sensitivity limitation for electron energies larger than several GeV. For example, for SLAC conditions the sensitivity of this method is 4 orders smaller than an appropriate one. We suggest to use a "dis-phased" slit target, where two semi-planes are turned with respect to each other at a small "dis-phased" angle. In order to ensure the interference between the diverged radiation beams we use a cylindrical lens. This method has much better sensitivity and resolution. A "dis-phased" angle 10 milliradians gives the optimal sensitivity to 5 microns transversal beam size. The theoretical model for calculating the ODR radiation from such targets (including focusing by cylindrical lens) is presented. It is shown that the sensitivity of this method does not depend on the Lorenz-factor directly. The target with the "dis-phased" angle 6.2 milliradians and the slit width 425 microns was manufactured for experimental test. Some preliminary experimental results are presented.