Extraction of single bunches of synchrotron radiation from storage rings with an X-ray chopper based on a rotating mirror

Kosciesza, D.; Bartunik, H.D.

doi:10.1107/s0909049599003404

Cited by 12 publications

(4 citation statements)

References 16 publications

(16 reference statements)

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“…[16][17][18][19] Among them, the rotating-disk-type chopper 20,21 and the solenoid-driven-type shutter can be candidates in the compact x-ray PIV system. For a rotating-disktype chopper, the disk configuration is almost fixed and the transmission frequency is controlled by adjusting the rotation speed of the disk.…”

Section: B X-ray Shutter and Synchronizationmentioning

confidence: 99%

Development of a compact x-ray particle image velocimetry for measuring opaque flows

Lee

Kim

Yim

et al. 2009

Review of Scientific Instruments

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A compact x-ray particle image velocimetry (PIV) system employing a medical x-ray tube as a light source was developed to measure quantitative velocity field information of opaque flows. The x-ray PIV system consists of a medical x-ray tube, an x-ray charge coupled device camera, a programmable shutter for a pulse-type x ray, and a synchronization device. Through performance tests, the feasibility of the developed x-ray PIV system as a flow measuring device was verified. To check the feasibility of the developed system, we tested a tube flow at two different mean velocities of 1 and 2 mm/s. The x-ray absorption of tracer particles must be quite different from that of working fluid to have a good contrast in x-ray images. All experiments were performed under atmospheric pressure condition. This system is unique and useful for investigating various opaque flows or flows inside opaque conduits.

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Section: B X-ray Shutter and Synchronizationmentioning

confidence: 99%

Development of a compact x-ray particle image velocimetry for measuring opaque flows

Lee

Kim

Yim

et al. 2009

Review of Scientific Instruments

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“…A method for extracting single bunches of synchrotron radiation using a rotating X-ray mirror has been developed and tested at DeSy in Hamburg. 71 Each bunch of electrons (and hence pulse of radiation) circulating in the ring is separated by at least 482 ns; the individual widths of the bunches are of the order of 100 ps, so this technique could be used in the study of reactions of that order. The mirror itself rotates relatively slowly, between 40 and 80 Hz, but as the conditions for re£ection are only met for a tiny fraction of the rotational range, it acts as an ef¢cient fast shutter, and can de¢ne a much shorter fully open condition than previously described ultrafast (*50 000 rpm) rotating shutters.…”

Section: Time-resolved Studiesmentioning

confidence: 99%

5 Molecular structure from X-ray diffraction

Powell

2000

Annu. Rep. Prog. Chem., Sect. C

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The last of these reports appeared four years ago; 1 a number of major advances in structure elucidation have appeared in laboratories in that period, mostly in the ¢eld of macromolecular structure determination. This is largely because sub-100 non-hydrogen atom structure solution has become almost routine, with extremely robust solution and re¢nement programs being complemented by rapid data collection from single crystal samples. In many cases, the role of the in-house crystallographer in chemistry departments is to provide a service to synthetic chemists in an analogous way to that of NMR spectroscopists ¢fteen or twenty years ago. Many chemical crystallographers have used this as an opportunity to study more dif¢cult structures, for example larger molecules from both single crystal and powder methods, using twin datasets, and looking more closely at structures in charge density studies.This increased ease has not removed the perils of being ``Marshed''; the well-known investigator into errors in space group determination has examined structures deposited into the Cambridge Structural Database (CSD) with space group P1, of which more than 20% are incorrect. 2 The majority of errors appear to be due to typographical errors in the original publication, but a signi¢cant minority are due to incorrect space group assignment (usually authors missing a centre of inversion, and assigning P1 rather than P1, or not recognizing higher symmetry, e.g., assigning P1 (triclinic) rather than C2 (monoclinic). However, the author notes that in some cases of true P1 structures, the deviation from centrosymmetry is as small as 0.1 Ð, and would be expected to lead to dif¢culties in re¢nement unless the problem had been recognized, as the following example illustrates.The solution and re¢nement of the antibiotics Emycin E and D provides a warning not to abide by conventional wisdom under all circumstances. 3 Both antibiotics crystallize in a triclinic space group with two molecules in the asymmetric unit (Z 2). The dataset for Emycin E was in accordance with the normal measure of centricity, a mean hjE 2 À 1ji value of 0.978 (the expected value for a centrosymmetric dataset is 0.968, and is 0.736 for acentric), while that for Emycin D was 0.829. Both can be re¢ned to low residual indices (R-factors) in space group

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“…The developments are based on earlier pioneering work performed in the 1980s in which the rotating slot design was analyzed (Mills, 1989;LeGrand et al, 1989). More recently, several alternatives to mechanical choppers, including designs based on a rotating mirror (Kosciesza & Bartunik, 1999), and by diffraction by acoustic surface waves (Tucoulou et al, 1998), and a rotating silicon crystal (McPherson et al, 2002), were analyzed. However, unlike mechanical shutters, not all these designs are applicable to pink-or white-beam experiments.…”

Section: Introductionmentioning

confidence: 99%

On the design of ultrafast shutters for time-resolved synchrotron experiments

Gembický

Coppens

2006

J Synchrotron Radiat

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A comprehensive treatment of the limitations and possibilities for single-pulse selection in synchrotron operating modes with approximately 150 ns bunch separation, as occurs in the standard operating mode at the Advanced Photon Source, is presented. It is shown that the strength of available materials and allowable kinetic energy build-up limit single-bunch selection for this separation to sample sizes of approximately 100 microm, and that for minimization of kinetic energy build-up it is preferable to increase the r.p.m. within physically acceptable limits rather than increase the disc radius to obtain a desirable peripheral speed. A slight modification of the equal-bunch spacing standard fill patterns is proposed that allows use of samples as large as 500 microm. The corresponding peripheral speed of the chopper wheel is approximately 600 m s(-1), which is within the limits of high-strength titanium alloys. For smaller samples, peripheral speeds are proportionally lower. Versatility can be achieved with interchangeable chopper wheels and the use of different orientations of the rotation axis relative to the X-ray beam, which opens the possibility of larger, rather than one-of-a-kind, production runs.

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Extraction of single bunches of synchrotron radiation from storage rings with an X-ray chopper based on a rotating mirror

Cited by 12 publications

References 16 publications

Development of a compact x-ray particle image velocimetry for measuring opaque flows

Development of a compact x-ray particle image velocimetry for measuring opaque flows

5 Molecular structure from X-ray diffraction

On the design of ultrafast shutters for time-resolved synchrotron experiments

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