Compensation of Aberration of Inclined X-ray Monochromators

Busetto, E.; Hrdý, J.

doi:10.1107/s0909049595012039

Cited by 3 publications

(8 citation statements)

References 10 publications

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“…This is essentially equivalent to the inclined case studied by Busetto & Hrdy Â (1995) with the beam horizontally deviated from the direction that would represent`pure inclined diffraction' by the angle $. To follow the procedure described by Busetto & Hrdy Â (1995), we must introduce the parameter X for the characterization of the impinging beam (Figs. 1 and 2).…”

Section: Theorymentioning

confidence: 99%

“…The purpose of this paper is to show that the results obtained by Busetto & Hrdy Â (1995) for the inclined double-crystal monochromator are essentially also valid (with some modi®cations) for the rotated-inclined double-crystal monochromator. This paper represents an extension of the work by Busetto & Hrdy Â (1995) and uses the same symbols and takes into consideration only a real point source. The effect of variable asymmetry within the horizontally divergent beam has been studied by Macrander & Lee (1992) and will not be taken into account here.…”

Section: Introductionmentioning

confidence: 99%

“…This was thoroughly discussed by Hrdy Â et al (1995). This aberration may be observable in the case of suf®ciently divergent radiation like the radiation from wigglers or bending magnets, provided that suf®-ciently large crystals are used.…”

Section: Introductionmentioning

confidence: 99%

“…(The dimensions of the crystals available at the present time restrict the usage of the inclined monochromator for rather narrow beams from undulators.) In subsequent work, Busetto & Hrdy Â (1995) showed that there exist two possible ways to compensate for this aberration in the inclined case. The ®rst one uses slightly different angles of inclination for the two crystals and the second one uses two double-crystal inclined (noncompensated) monochromators with opposite angles of inclination with respect to each other.…”

Section: Introductionmentioning

confidence: 99%

“…the survey of Busetto & Hrdy Â, 1995). The asymmetric monochromator is based on the well known asymmetric diffraction.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Rotated-inclined double-crystal monochromator for synchrotron radiation: aberration and its compensation

Hrdý

Busetto

1998

J Synchrotron Radiat

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A rotated-inclined double-crystal X-ray monochromator was designed for high-power undulator beamlines for SPring-8 to reduce the impinging radiation power density. Recently, it has been shown that an inclined double-crystal monochromator suffers from a certain type of geometrical aberration that may be relatively easily compensated. In this paper, it is shown that a similar aberration exists also in the case of rotated-inclined monochromators and that as in the inclined case the aberration may also be compensated.

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Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…the survey of Busetto & Hrdy Â, 1995). The asymmetric monochromator is based on the well known asymmetric diffraction.…”

Section: Introductionmentioning

confidence: 99%

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Rotated-inclined double-crystal monochromator for synchrotron radiation: aberration and its compensation

Hrdý

Busetto

1998

J Synchrotron Radiat

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Surgical Weight Loss: Impact on Energy Expenditure

et al. 2012

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Diet-induced weight loss is often limited in its magnitude and often of short duration, followed by weight regain. On the contrary, bariatric surgery now commonly used in the treatment of severe obesity favors large and sustained weight loss, with resolution or improvement of most obesity-associated comorbidities. The mechanisms of sustained weight loss are not well understood. Whether changes in the various components of energy expenditure favor weight maintenance after bariatric surgery is unclear. While the impact of diet-induced weight loss on energy expenditure has been widely studied and reviewed, the impact of bariatric surgery on total energy expenditure, resting energy expenditure, and diet-induced thermogenesis remains unclear. Here, we review data on energy expenditure after bariatric surgery from animal and human studies. Bariatric surgery results in decreased total energy expenditure, mainly due to reduced resting energy expenditure and explained by a decreased in both fat-free mass and fat mass. Limited data suggest increased diet-induced thermogenesis after gastric bypass, a surgery that results in gut anatomical changes and modified the digestion processes. Physical activity and sustained intakes of dietary protein may be the best strategies available to increase non-resting and then total energy expenditure, as well as to prevent the decline in lean mass and resting energy expenditure.

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Asymmetric-cut variable-incident-angle monochromator

Smither

Graber

Fernández

et al. 2012

Review of Scientific Instruments

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A novel asymmetric-cut variable-incident-angle monochromator was constructed and tested in 1997 at the Advanced Photon Source of Argonne National Laboratory. The monochromator was originally designed as a high heat load monochromator capable of handling 5-10 kW beams from a wiggler source. This was accomplished by spreading the x-ray beam out on the surface an asymmetric-cut crystal and by using liquid metal cooling of the first crystal. The monochromator turned out to be a highly versatile monochromator that could perform many different types of experiments. The monochromator consisted of two 18° asymmetrically cut Si crystals that could be rotated about 3 independent axes. The first stage (Φ) rotates the crystal around an axis perpendicular to the diffraction plane. This rotation changes the angle of the incident beam with the surface of the crystal without changing the Bragg angle. The second rotation (Ψ) is perpendicular to the first and is used to control the shape of the beam footprint on the crystal. The third rotation (Θ) controls the Bragg angle. Besides the high heat load application, the use of asymmetrically cut crystals allows one to increase or decrease the acceptance angle for crystal diffraction of a monochromatic x-ray beam and allows one to increase or decrease the wavelength bandwidth of the diffraction of a continuum source like a bending-magnet beam or a normal x-ray-tube source. When the monochromator is used in the doubly expanding mode, it is possible to expand the vertical size of the double-diffracted beam by a factor of 10-15. When this was combined with a bending magnet source, it was possible to generate an 8 keV area beam, 16 mm wide by 26 mm high with a uniform intensity and parallel to 1.2 arc sec that could be applied in imaging experiments.

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Compensation of Aberration of Inclined X-ray Monochromators

Cited by 3 publications

References 10 publications

Rotated-inclined double-crystal monochromator for synchrotron radiation: aberration and its compensation

Rotated-inclined double-crystal monochromator for synchrotron radiation: aberration and its compensation

Surgical Weight Loss: Impact on Energy Expenditure

Asymmetric-cut variable-incident-angle monochromator

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