Plasma density from Cerenkov radiation, betatron oscillations, and beam steering in a plasma wakefield experiment at 30 GeV

Catravas, P. ; Chattopadhyay, S. ; Esarey, E. ; Leemans, W.P. ; Assmann, R. ; Decker, F.-J. ; Hogan, M.J. ; Iverson, R. ; Siemann, R.H. ; Walz, D. ; Whittum, D. ; Blue, B. ; Clayton, C. ; Joshi, C. ; Marsh, K. ; Mori, W.B. ; Wang, S. ; Katsouleas, T. ; Lee, S. ; Muggli, P.

Lawrence Berkeley National Laboratory

关键词: Diagnostic Techniques Plasma Wakefield Acceleration Cerenkov Radiation Plasma Density Diagnostic Atomic Spectral Lines;    Wavelengths;    Synchronization;    Cherenkov Radiation;    Lithium;   

DOI  :  10.2172/787115
RP-ID  :  LBNL--47632
RP-ID  :  AC03-76SF00098
RP-ID  :  787115

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来源: UNT Digital Library

【 摘 要 】

A method for using Cerenkov radiation near atomic spectral lines to measure plasma source properties for plasma wakefield applications has been discussed and experimentally verified. Because the radiation co-propagates with the electron beam, the radiation samples the source properties exactly along the path of interest with perfect temporal synchronization. Observation wavelengths were chosen with respect to the atomic resonances of the plasma source, where the relative change in the index of refraction strongly affects the Cerenkov cone angle, and permits flexible diagnostic design. The Cerenkov spatial profiles were systematically studied for a Lithium heat pipe oven as a function of oven temperature and observation wavelength. Neutral densities and plasma densities were extracted from the measurements.