The LCLS variable-energy hard X-ray single-shot spectrometer

2016 ◽  
Vol 23 (1) ◽  
pp. 3-9 ◽  
Author(s):  
David Rich ◽  
Diling Zhu ◽  
James Turner ◽  
Dehong Zhang ◽  
Bruce Hill ◽  
...  
Keyword(s):  
Imaging System ◽  
Low Noise ◽  
Single Shot ◽  
X Ray ◽  
Performance Improvements ◽  
Spatially Resolved ◽  
Optical Imaging System ◽  
And Performance ◽  
Thin Crystal ◽  
Variable Energy

The engineering design, implementation, operation and performance of the new variable-energy hard X-ray single-shot spectrometer (HXSSS) for the LCLS free-electron laser (FEL) are reported. The HXSSS system is based on a cylindrically bent Si thin crystal for dispersing the incident polychromatic FEL beam. A spatially resolved detector system consisting of a Ce:YAG X-ray scintillator screen, an optical imaging system and a low-noise pixelated optical camera is used to record the spectrograph. The HXSSS provides single-shot spectrum measurements for users whose experiments depend critically on the knowledge of the self-amplified spontaneous emission FEL spectrum. It also helps accelerator physicists for the continuing studies and optimization of self-seeding, various improved mechanisms for lasing mechanisms, and FEL performance improvements. The designed operating energy range of the HXSSS is from 4 to 20 keV, with the spectral range of order larger than 2% and a spectral resolution of 2 × 10−5or better. Those performance goals have all been achieved during the commissioning of the HXSSS.

Single-shot arrival timing diagnostics for a soft X-ray free-electron laser beamline at SACLA

2018 ◽  
Vol 25 (1) ◽  
pp. 68-71 ◽  
Author(s):  
Shigeki Owada ◽  
Kyo Nakajima ◽  
Tadashi Togashi ◽  
Tetsuo Kayatama ◽  
Makina Yabashi
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Imaging System ◽  
Laser Pulses ◽  
Single Shot ◽  
Simultaneous Operation ◽  
One Dimensional ◽  
X Ray ◽  
Arrival Timing ◽  
Optical Laser

Arrival timing diagnostics performed at a soft X-ray free-electron laser (FEL) beamline of SACLA are described. Intense soft X-ray FEL pulses with one-dimensional focusing efficiently induce transient changes of optical reflectivity on the surface of GaAs. The arrival timing between soft X-ray FEL and optical laser pulses was successfully measured as a spatial position of the reflectivity change. The temporal resolution evaluated from the imaging system reaches ∼10 fs. This method requires only a small portion of the incident pulse energy, which enables the simultaneous operation of the arrival timing diagnostics and experiments by introducing a wavefront-splitting scheme.

scholarly journals Simultaneous dual-energy X-ray stereo imaging

2015 ◽  
Vol 22 (4) ◽  
pp. 1078-1082 ◽  
Author(s):  
Rajmund Mokso ◽  
Peter Oberta
Keyword(s):  
Dynamic Systems ◽  
Imaging System ◽  
Dual Energy ◽  
Mutual Position ◽  
Single Shot ◽  
Splitting Scheme ◽  
Stereo Imaging ◽  
Synchrotron Source ◽  
X Ray

Dual-energy orK-edge imaging is used to enhance contrast between two or more materials in an object and is routinely realised by acquiring two separate X-ray images each at different X-ray wavelength. On a broadband synchrotron source an imaging system to acquire the two images simultaneously was realised. The single-shot approach allows dual-energy and stereo imaging to be applied to dynamic systems. Using a Laue–Bragg crystal splitting scheme, the X-ray beam was split into two and the two beam branches could be easily tuned to either the same or to two different wavelengths. Due to the crystals' mutual position, the two beam branches intercept each other under a non-zero angle and create a stereoscopic setup.

TAGUCHI METHOD-BASED OPTIMIZATION OF THE MINIMUM DETECTABLE DIFFERENCE OF A CARDIAC X-RAY IMAGING SYSTEM USING A PRECISE LINE PAIR GAUGE

2019 ◽  
Vol 19 (07) ◽  
pp. 1940030 ◽  
Author(s):  
LUNG-FA PAN ◽  
KENG-YI WU ◽  
KE-LIN CHEN ◽  
SAMRIT KITTIPAYAK ◽  
LUNG-KWANG PAN
Keyword(s):  
Spatial Resolution ◽  
Imaging System ◽  
Low Noise ◽  
Optimal Combination ◽  
Line Pair ◽  
Test Analysis ◽  
X Ray ◽  
X Ray Imaging ◽  
Detectable Difference ◽  
Minimum Detectable Difference

Objective: To optimize the minimum detectable difference (MDD) of a cardiac X-ray imaging system using the Taguchi L8(27) analysis and a precise line pair (LP) gauge. Methods: The optimal combination of the four critical factors of the cardiac X-ray imaging system, namely X-ray focus, kilovoltage (kVp), milliamper-seconds (mAs) and source image distance (SID), providing the MDD was calculated via the Taguchi analysis and experimentally verified. Two (low and high) levels were assigned for each factor, and eight combinations of four factors were used to acquire instant X-ray images using an NDT commercial LP gauge (with a gauge length of 64[Formula: see text]mm and a width of [Formula: see text][Formula: see text]mm). The latter had five lines and was split gradually from top to bottom for the inspection of X-ray images, whose quality was ranked by three well-trained radiologists according to the double-blind criterion. The ranking grade was given by sharp contrast, low noise and precision to distinguish the LP. Accordingly, the MDD was derived to represent the spatial resolution of instant X-ray images by the revised Student’s [Formula: see text]-test analysis. The optimal combination of factors was experimentally identified and clinically verified in the follow-up inspections. Results: For the conventional setting, Group No. 7 (which obtained the highest grade among eight groups) and the optimal setting, the obtained MDD values were [Formula: see text], [Formula: see text] and [Formula: see text][Formula: see text]mm, respectively, while the LP (line pair/mm) interpolated from the gauge scale amounted to [Formula: see text], [Formula: see text] and [Formula: see text][Formula: see text]LP/mm, respectively. Conclusion: The Taguchi L8 analysis was proved to be instrumental in optimizing the cardiac X-ray imaging system MDD and is recommended to be used jointly with the revised Student’s [Formula: see text]-test analysis for improving the spatial resolution of instant X-ray images.

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