Resonant transition radiation in the X-ray region from a low emittance 855 MeV electron beam

Backe, H.; Gampert, S.; Grendel, A.; Hartmann, Hermann; Lauth, W.; Weinheimer, C.; Zahn, R.; Buskirk, F.R.; Euteneuer, H.; Kaiser, K.-H.; Stephan, G.; Walcher, Th.

doi:10.1007/bf01296337

Cited by 21 publications

(3 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was suggested more than fifteen years ago by Moran et al [28] that the interfoil coherence of TR, generated by relativistic electrons, constitutes a new technique for the measurement of the refractive index decrement δ(ω) in the X-ray region. A number of experiments were performed in the soft and hard X-ray region in which more or less clear interference structures were observed [28,29,30,31,32,1]. However, that δ(ω) really can be measured by such a technique has been demonstrated first by the X-ray interferometer described in this work.…”

Section: The Hard X-ray Interferometermentioning

confidence: 99%

Coherent X-rays at MAMI

et al. 2006

Self Cite

View full text Add to dashboard Cite

Abstract. Coherent radiation in the range from soft X-rays up to hard X-rays, produced by the lowemittance electron beam of MAMI, can be used for various applications. Novel types of interferometers have been developed for the measurement of the complex index of refraction of thin self-supporting foils. For the vacuum ultraviolet and soft X-ray region the interferometer consists of two collinear undulators, and a grating spectrometer. A foil placed between the undulators causes a phase shift and an attenuation of the oscillation amplitude. The complex index of refraction has been measured at the L 2,3-absorption edges of nickel. A novel method is described for the measurement of the X-ray magnetic circular birefringence. For the hard X-ray region the interferometer consists of two foils at which the 855 MeV electron beam produces transition radiation. Distinct interference oscillations have been observed as a function of both, the photon emission angle and the distance between the foils. The refractive index decrement δ(ω) of a 2 µm thick nickel sample foil has been measured at X-ray energies around the K absorption edge at 8333 eV and at 9930 eV with an accuracy of better than 1.5 %. The line width of parametric X radiation (PXR) was measured in backward geometry with a Si single-crystal monochromator. Upper limits of the line width of 42 meV, 50 meV, and 44 meV, have been determined for the (333), (444) and (555) reflections at photon energies of 5932 eV, 7909 eV, and 9887 eV, respectively. Small angle scattering of the electrons in the crystal leads to a stochastic frequency modulation of the exponentially damped wave train which results in the line broadening. To elucidate the quest if the production of PXR is a kinematical or a dynamical process the radiation from silicon single-crystal targets, emitted close to the electron direction, has been studied. The observed interference structures and the narrow-band radiation in forward direction shows that PXR is produced in a dynamical process. .Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity) -41.60.-m Radiation by moving charges -41.50.+h X-ray beams and X-ray optics PACS.

show abstract

Section: The Hard X-ray Interferometermentioning

confidence: 99%

Coherent X-rays at MAMI

et al. 2006

Self Cite

View full text Add to dashboard Cite

show abstract

“…In addition, quite inexpensive compact linear accelerators are currently under development for fundamental research in high energy physics (e.g., the TESLA project) [12]. Based on such a scenario we felt that it might be appropriate to investigate the feasibility for DESA with transition radiation (TR) produced by 1 GeV electron beam which traverses an optimized stack of thin foils [13], [14]. Our approach aims at a very efficient use of the available photon flux.…”

Section: Introductionmentioning

confidence: 99%

Novel digital K-edge imaging system with transition radiation from an 855-MeV electron beam

Hagenbuck

Backe

Clawiter

et al. 2001

IEEE Trans. Nucl. Sci.

Self Cite

View full text Add to dashboard Cite

A novel K-edge imaging method has been developed at the Mainz Microtron MAMI aiming at a very efficient use of the transition radiation (TR) flux generated by the external 855 MeV electron beam in a foil stack. A fan-like quasi-monochromatic hard X-ray beam is produced from the ¦1 mrad wide TR cone with a highly oriented pyrolytic graphite (HOPG) crystal. The absorption of the object in front of a 30 mm ¢ 10 mm pn-CCD photon detector is measured at every pixel by a broad-band energy scan around the K-absorption edge. This is accomplished by a synchronous variation of the lateral crystal position and the electron beam direction which defines also the direction of the TR cone. The system has been checked with a phantom consisting of a 2.5 µm thick molybdenum sample embedded in a 136 or 272 µm thick copper bulk foil. A numerical analysis of the energy spectrum for every pixel demonstrates that data as far as ¦ 0.75 keV away from the K edge of molybdenum at 20 keV still improve the signal-to-noise ratio. Prospects are discussed to investigate the human lungs with xenon as a contrast agent at the available total primary photon flux of 2 ¢10 10 /(s¡ 0.1% bandwidth (BW)) only.

show abstract

“…For a complete understanding of the radiation emitted at 180 ± , contributions of transition radiation (TR), originating at the vacuum-crystal surface due to the different dielectric constants between vacuum and material, which are diffracted into the backward direction have to be taken into account [5,18]. This contribution can be described by [19] …”

mentioning

confidence: 99%

Parametric X Rays Observed under Bragg Condition: Boost of Intensity by a Factor of Two

Freudenberger¹,

Genz²,

Morokhovskyi³

et al. 2000

Phys. Rev. Lett.

View full text Add to dashboard Cite

Parametric x rays (PXR) produced by bombarding silicon and diamond crystals with electrons of 30 to 87 MeV were detected at 180 degrees relative to the direction of the electron beam. It was found that the dependence of the intensity on the orientation of the crystal agrees with the predictions of the kinematical theory of PXR. The absolute intensity is twice as large as predicted. These findings can be explained considering dynamical effects that govern the x-ray crystal interaction. Additionally, x rays caused by self-diffracted transition radiation have been observed.

show abstract

Resonant transition radiation in the X-ray region from a low emittance 855 MeV electron beam

Cited by 21 publications

References 15 publications

Coherent X-rays at MAMI

Coherent X-rays at MAMI

Novel digital K-edge imaging system with transition radiation from an 855-MeV electron beam

Parametric X Rays Observed under Bragg Condition: Boost of Intensity by a Factor of Two

Contact Info

Product

Resources

About