Optics and bremsstrahlung estimates for channeling radiation experiments at FAST

Abstract

This paper presents X-ray spectra of channeling radiation (CR) expected at the FAST (Fermi Accelerator Science and Technology) facility in Fermilab. Our purpose is to produce high brightness quasi-monochromatic X-rays in an energy range from 40 keV to 110 keV. We will use a diamond crystal and low emittance electrons with an energy of around 43 MeV. The quality of emitted X-rays strongly depends on parameters of the electron beam at the crystal. We present simulations of the beam optics for high brightness and high yield operations with bunch charges of 1 pC, 20 pC, and 200 pC. We estimate the X-ray spectra including bremsstrahlung background for a charge of 20 pC. The electron beam distributions with and without channeling in the diamond crystal are calculated. We discuss an X-ray detector system to avoid pile-up effect during high charge operations.where is the angle of the emitted photon from the incident electron, ! and ! are the energy eigenvalues of electrons in energy levels and . This equation also shows that the CR energy can be tuned by changing the electron energy since ! ∝ ! . The CR spectrum calculations reported here were done using a Mathematica notebook which was significantly corrected and modified from the published version [11], this modified version was used to successfully compare simulations with experimental results from a previous channeling experiment [8]. The CR

GAMMA-RADIATION SPECTRA OF 1200 MeV ELECTRONS IN THICK BERYLLIUM, SILICON AND TUNGSTEN SINGLE CRYSTALS

“…Similar investigations at the low electrons energy are given in papers [5][6][7][8] and in the recent years in papers [13][14][15].…”

“…Interest to the channeling radiation of the electrons was amplified after the idea about a possibility of its application as intensive and easily tunable source quasi monoenergetic X-ray and gamma radiation [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and also as the positrons source for the linear supercolliders [16].…”

“…The gamma radiation spectra from Be crystal are given in paper [12]. The main attention was paid to optimization of the yield and the spectral line width of the gamma radiation [2,11] and [13][14][15].…”

IOTA (Integrable Optics Test Accelerator): facility and experimental beam physics program

“…Past experiments with electron energies below 30 MeV have reported ratios of the CR peak to the BS background in the range from 6 to 10. Figure 28 shows the expected CR spectrum with 43 MeV electrons under three different assumptions for the channeling yield, compared to the expected BS background [71]. There are CR lines at (51,68,110) keV and the ratio of the CR peak at 110 keV to BS ranges from 4 to 15 in this calculation.…”

Experience with crystals at Fermilab accelerators

“…4. Crystal channeling radiation experiment at FAST: a) schematic view of the experiment; b) crystal goniometer assembly; c) crystal goniometer assembly installed in low energy electron beamline; d) energy spectrum of emitted X-rays (adapted from 16,17 ).…”