Diamonds for high reflectivity (normal incidence) SR-Monochromators

Stephenson, J. D.

doi:10.1002/pssa.2211380108

Cited by 5 publications

(5 citation statements)

References 14 publications

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“…Theoretical estimates of efficiency of the diamond monochromators are presented in [21], the first practical application of diamonds for monochromatization of SR beam was performed at the ESRF European Synchrotron Radiation Facility (Grenoble, France) [22][23][24]. Later, diamond monochromators were mounted on high-brilliance undulator channels at the APS (USA) [25] and Spring-8 (Japan) sources [26,27].…”

Section: Equipment Of Experimental Stations For High Precision Powdermentioning

confidence: 99%

High precision X-ray diffraction studies of polycrystalline materials on synchrotron radiation

Shmakov

2012

J Struct Chem

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The review is devoted to application of synchrotron radiation (SR) for studying the structure of polycrystalline materials. The main emphasis is made on the equipment and techniques for acquiring high precision structural information -high angular resolution powder diffractometry and the use of anomalous scattering effect in structural studies. Various schemes of recording the high resolution X-ray patterns are presented, diffractometers operating in the world's leading synchrotron radiation centers are described, and examples of particular applications are reported. S134 space, simplicity and reliability of such X-ray radiation source provided its wide use. X-ray tubes with Ti, Cr, Fe, Co, Ni, Cu, Mo and Ag anodes are intensively employed in modern lab-scale diffractometers.The radiation intensity of X-ray tube is limited by the efficiency of heat removal from the anode. At the average anode current of 100 mA and voltage of 100 kV, a 10 kW power is released at the ∼1 mm 2 anode area. In the process, no more than 3% of the power is re-emitted in the X-ray range. Such mode of operation can be provided only by the tubes with a rotating anode, where the released power is distributed over a large surface area of the anode. At the same time, intensity of the radiation source determines numerous parameters of an X-ray diffractometer -the acquisition time of X-ray pattern, angular resolution, sensitivity of X-ray diffraction analysis, accuracy of experimental data, etc. Improvement of the source would open a way to radically new possibilities of X-ray diffraction studies.In the middle of the last century, the development of elementary particle physics resulted in creating the cyclic accelerators and then the storage rings, where charged high-energy particles follow the closed trajectories and collide at a site where beams meet to generate fluxes of particles -products of the interaction. Such experimental scheme provides a double gain in energy as compared to the case when accelerated particles are directed to a stationary heavy target. The particle flux density in counter beams is much lower than density of the target, so the probability of particles collision is also much lower. Nevertheless, the multiple -several million times a second -repetition of beam collisions gives an acceptable statistics for reasonable times. If the colliding particles have equal weights and opposite charges, counter beams can be stored in a single ring chamber, dimensions of the setup being halved at the retained energy of the particles. Cyclic colliders are very productive devices for elementary particle physics; however, a serious problem arose at the early stage of their applicationlosses of particle energy for radiation [4].Motion of a charged particle along a curved trajectory is accompanied by emission of electromagnetic radiation, the so-called magnetodeceleration or synchrotron radiation. Designers of cyclic accelerators tried to minimize the radiation losses, which resulted mainly in an increased size of setups; these losses were c...

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Section: Equipment Of Experimental Stations For High Precision Powdermentioning

confidence: 99%

High precision X-ray diffraction studies of polycrystalline materials on synchrotron radiation

Shmakov

2012

J Struct Chem

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“…The general and normal incidence Bragg conditions for two-beam diffraction (excluding simultaneous reflections, see [2]) shown in Fig. 1, indicate I: the incident beam, I , the Bragg-diffracted, and 1 : the transmitted intensity.…”

Section: Theorymentioning

confidence: 99%

“…The symbols used are those defined in [l] and the calculations were performed using the constants listed in Table 1 of [2]. Specific (normal incidence) values for the reflectivity, transmittivity and corresponding crystal thickness for both XFEL and 'thick crystal' cases are recorded in Table 1 (this note) Table 1 A comparison between diamond, Si, and Ge reflectivities (R) and transmittivities ( T ) vs. crystal thickness (to) at OH = n/2 rad for z = 10-', see [2] XFEL thick crystal…”

Section: Theorymentioning

confidence: 99%

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Optimised (normal incidence) reflectivity and transmittivity coefficients for diamond, Si, and Ge XFEL monochromators

Stephenson

1994

Phys. Stat. Sol. (a)

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“…Diamond has been investigated for use in solid state devices for high power and high frequency applications that can operate in a radiation environment or at high temperature [1]. For high heat-load optical components used in synchrotron radiation system or the free electron laser, a diamond single crystal was reported to be superior to other monochromator materials [2,3]. To develop reproducible doping techniques of electrically active impurities, knowledge of electric and annealing properties of point defects is crucial.…”

Section: Introductionmentioning

confidence: 99%

Annealing behaviours of defects in electron-irradiated diamond probed by positron annihilation

Uedono

Mori

Morishita³

et al. 1999

J. Phys.: Condens. Matter

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Annealing behaviours of defects in electron-irradiated diamond were studied using the positron annihilation technique. For a type IIa specimen after 3 MeV electron irradiation with a dose of 1 × 1018 cm-2, the major species of vacancy-type defects was determined to be neutral monovacancies, V0. The trapping rate of positrons by V0 decreased above 600 °C annealing, but the annihilation mode of positrons trapped by vacancy-type defects was observed even after 900 °C annealing. For a type Ib specimen after the irradiation, the major species of vacancy-type defects was determined to be negative monovacancies, and the formation of nitrogen-monovacancy pairs, N-V, was observed after 650 °C annealing. The annihilation probability between positrons and electrons with a broad momentum distribution was found to be increased by the trapping of positrons by N-V.

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Diamonds for high reflectivity (normal incidence) SR-Monochromators

Cited by 5 publications

References 14 publications

High precision X-ray diffraction studies of polycrystalline materials on synchrotron radiation

High precision X-ray diffraction studies of polycrystalline materials on synchrotron radiation

Optimised (normal incidence) reflectivity and transmittivity coefficients for diamond, Si, and Ge XFEL monochromators

Annealing behaviours of defects in electron-irradiated diamond probed by positron annihilation

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