Influence of real photon diffraction on parametric X-ray radiation angular distribution in thin perfect crystals

Phys. Rev. Accel. Beams

Laktionova

Shatokhin

et al. 2019

A technique is proposed for determining beam dimensions on a target by measuring two-dimensional angular distributions of the radiation for two distances between the crystal where the radiation is generated and a coordinate detector. The dimensions are determined from the results of a least squares method procedure with varying parameters, where the adjustable function is the distribution for a shorter distance and the fitting function is the convolution of the angular distribution at a greater distance with a twodimensional Gaussian distribution whose parameters are uniquely related to the beam dimensions on the target and the distances between the crystal and the detector. The minimum measured beam sizes are about 50-60 μm for the parametric x-ray mechanism and an electron energy of less than 1 GeV and 10-15 μm for the mechanism of diffracted transition radiation and electrons with an energy above several GeV.

Section: Proposed Measurement Techniquesupporting

confidence: 82%

New method of electron beam transverse size measurement by angular distribution of emission in a thin crystal

Phys. Rev. Accel. Beams

Laktionova

Shatokhin

et al. 2019

“…It has been reported that for electrons with an energy of several tens of GeV, the angular density of emission intensity at the center of the diffraction spot is much lower for PXR with a dip width of several mrad for this observation angle than for DTR with the characteristic emission angle about −1 concentrated near the Bragg's direction [13,14,21]. Because of the same nature of volume and surface emissions, we may expect a similar relationship between surface PXR and DDR.…”

Section: Theoretical Considerationsmentioning

confidence: 70%

Diffracted diffraction radiation and its application to beam diagnostics

Nuclear Instruments and Methods in Physics Research Section A:

Shatokhin

Sumitani

et al. 2018

Self Cite

We present theoretical considerations for diffracted diffraction radiation and also propose an application of this process to diagnosing ultra-relativistic electron (positron) beams for the first time. Diffraction radiation is produced when relativistic particles move near a target. If the target is a crystal or X-ray mirror, diffraction radiation in the X-ray region is expected to be diffracted at the Bragg angle and therefore be detectable. We present a scheme for applying this process to measurements of the beam angular spread, and consider how to conduct a proof-of-principle experiment for the proposed method.

“…As shown in [16] and was confirmed in [17,18], the contribution of transition-radiation diffraction at the reflection center becomes much larger than that of PXR as the electron energy increases to 5 GeV. For an electron energy of 10 GeV, the angular density of DTR exceeds that of PXR by a factor of 500 or more because of a sharp decrease in the characteristic radiation angle determining the angular distribution of the transition radiation, and, consequently, of DTR.…”

Section: We Assume Thatmentioning

confidence: 73%

“…The presence of the bright peak in the angular radiation distribution [16,23], whose form is like that of the angular PXR distribution, in Figs. 1 and 3, makes it possible also to use the above procedure to determine the dimensions of a high-energy electron beam.…”

Section: We Assume Thatmentioning

confidence: 75%

Proposal for a Procedure for Measuring the Transverse Dimensions of a Beam of Relativistic Electrons with a Small Longitudinal Size

Vnukov

Laktionova

et al. 2020

J. Synch. Investig.

The possibility of implementing a previously proposed procedure for determining the beam dimensions at a target is analyzed; it includes the measurement of two-dimensional angular distributions of the coherent radiation of fast electrons for two distances between a crystal, where radiation is generated, and a coordinate detector. The use of two mechanisms of parametric X-ray radiation and diffracted transition radiation is considered. The limits of the method sensitivity and the influence of the departure of secondary electrons and photons on them are discussed.