scholarly journals A Compton Backscattering Polarimeter for Electron Beams below 1 GeV

2019 ◽  
Vol 7 ◽  
pp. 130
Author(s):  
N. P. Vodinas ◽  
D. W. Higinbotham ◽  
C. W. De Jager ◽  
N. H. Papadakis ◽  
I. Passchier

A recently installed polarized electron source will allow internal target experiments to be performed with polarized electrons at the NIKHEF Internal Target Hall, lb measure the longitudinal component of the polarization vector of the stored electron beam, a Polarimeter based on spin-dependent Compton scattering has been developed and successfully commissioned

2004 ◽  
Vol 22 (3) ◽  
pp. 221-244 ◽  
Author(s):  
F.V. HARTEMANN ◽  
A.M. TREMAINE ◽  
S.G. ANDERSON ◽  
C.P.J. BARTY ◽  
S.M. BETTS ◽  
...  

The Compton scattering of a terawatt-class, femtosecond laser pulse by a high-brightness, relativistic electron beam has been demonstrated as a viable approach toward compact, tunable sources of bright, femtosecond, hard X-ray flashes. The main focus of this article is a detailed description of such a novel X-ray source, namely the PLEIADES (Picosecond Laser–Electron Inter-Action for the Dynamical Evaluation of Structures) facility at Lawrence Livermore National Laboratory. PLEIADES has produced first light at 70 keV, thus enabling critical applications, such as advanced backlighting for the National Ignition Facility andin situtime-resolved studies of high-Zmaterials. To date, the electron beam has been focused down to σx= σy= 27 μm rms, at 57 MeV, with 266 pC of charge, a relative energy spread of 0.2%, a normalized horizontal emittance of 3.5 mm·mrad, a normalized vertical emittance of 11 mm·mrad, and a duration of 3 ps rms. The compressed laser pulse energy at focus is 480 mJ, the pulse duration 54 fs Intensity Full Width at Half-Maximum (IFWHM), and the 1/e2radius 36 μm. Initial X rays produced by head-on collisions between the laser and electron beams at a repetition rate of 10 Hz were captured with a cooled CCD using a CsI scintillator; the peak photon energy was approximately 78 keV, and the observed angular distribution was found to agree very well with three-dimensional codes. The current X-ray dose is 3 × 106photons per pulse, and the inferred peak brightness exceeds 1015photons/(mm2× mrad2× s × 0.1% bandwidth). Spectral measurements using calibrated foils of variable thickness are consistent with theory. Measurements of the X-ray dose as a function of the delay between the laser and electron beams show a 24-ps full width at half maximum (FWHM) window, as predicted by theory, in contrast with a measured timing jitter of 1.2 ps, which contributes to the stability of the source. In addition,K-edge radiographs of a Ta foil obtained at different electron beam energies clearly demonstrate the γ2-tunability of the source and show very good agreement with the theoretical divergence-angle dependence of the X-ray spectrum. Finally, electron bunch shortening experiments using velocity compression have also been performed and durations as short as 300 fs rms have been observed using coherent transition radiation; the corresponding inferred peak X-ray flux approaches 1019photons/s.


Author(s):  
D. E. Speliotis

The interaction of electron beams with a large variety of materials for information storage has been the subject of numerous proposals and studies in the recent literature. The materials range from photographic to thermoplastic and magnetic, and the interactions with the electron beam for writing and reading the information utilize the energy, or the current, or even the magnetic field associated with the electron beam.


Author(s):  
Tamotsu Ohno

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.


1970 ◽  
Vol 4 (12) ◽  
pp. 525-528 ◽  
Author(s):  
P. Christillin ◽  
E. Remiddi

2016 ◽  
Vol 42 (1) ◽  
pp. 96-99 ◽  
Author(s):  
A. S. Klimov ◽  
V. A. Burdovitsin ◽  
A. A. Grishkov ◽  
E. M. Oks ◽  
A. A. Zenin ◽  
...  

2008 ◽  
Vol 26 (4) ◽  
pp. 605-617 ◽  
Author(s):  
V.F. Tarasenko ◽  
E.H. Baksht ◽  
A.G. Burachenko ◽  
I.D. Kostyrya ◽  
M.I. Lomaev ◽  
...  

AbstractThis paper reports on the properties of a supershort avalanche electron beam generated in the air or other gases under atmospheric pressure and gives the analysis of a generation mechanism of supershort avalanche electron beam, as well as methods of such electron beams registration. It is reported that in the air under the pressure of 1 atm, a supershort (<100 ps) avalanche electron beam is formed in the solid angle more than 2π steradian. The electron beam has been obtained behind a 45 µm thick Al-Be foil in SF6 and Xe under the pressure of 2 atm, and in He, under the pressure of about 15 atm. It is shown that in SF6 under the high pressure (>1 atm) duration (full width at half maximum) of supershort avalanche electron beam pulse is about 150 ps.


2013 ◽  
Vol 31 (8) ◽  
pp. 1379-1385 ◽  
Author(s):  
A. Voshchepynets ◽  
V. Krasnoselskikh

Abstract. In this work, we studied the effects of background plasma density fluctuations on the relaxation of electron beams. For the study, we assumed that the level of fluctuations was so high that the majority of Langmuir waves generated as a result of beam-plasma instability were trapped inside density depletions. The system can be considered as a good model for describing beam-plasma interactions in the solar wind. Here we show that due to the effect of wave trapping, beam relaxation slows significantly. As a result, the length of relaxation for the electron beam in such an inhomogeneous plasma is much longer than in a homogeneous plasma. Additionally, for sufficiently narrow beams, the process of relaxation is accompanied by transformation of significant part of the beam kinetic energy to energy of accelerated particles. They form the tail of the distribution and can carry up to 50% of the initial beam energy flux.


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