Laser power meters as x-ray intensity monitors for LCLS-II (Conference Presentation)

2017 ◽  
Author(s):  
Philip A. Heimann ◽  
Stefan P. Moeller ◽  
Sergio Carbajo Garcia ◽  
Sanghoon Song ◽  
Yiping Feng ◽  
...  
Keyword(s):  
Laser Power ◽  
X Ray

scholarly journals Laser power meters as an X-ray power diagnostic for LCLS-II

2018 ◽  
Vol 25 (1) ◽  
pp. 72-76 ◽  
Author(s):  
Philip Heimann ◽  
Stefan Moeller ◽  
Sergio Carbajo ◽  
Sanghoon Song ◽  
Georgi Dakovski ◽  
...  
Keyword(s):  
Free Electron Laser ◽  
Laser Power ◽  
High Vacuum ◽  
Average Power ◽  
Gas Analysis ◽  
Ultra High Vacuum ◽  
Beam Path ◽  
X Ray ◽  
High Repetition ◽  
Residual Gas

For the LCLS-II X-ray instruments, laser power meters are being developed as compact X-ray power diagnostics to operate at soft and tender X-ray photon energies. These diagnostics can be installed at various locations along an X-ray free-electron laser (FEL) beamline in order to monitor the transmission of X-ray optics along the beam path. In addition, the power meters will be used to determine the absolute X-ray power at the endstations. Here, thermopile power meters, which measure average power, and have been chosen primarily for their compatibility with the high repetition rates at LCLS-II, are evaluated. A number of characteristics in the soft X-ray range are presented including linearity, calibrations conducted with a photodiode and a gas monitor detector as well as ultra-high-vacuum compatibility tests using residual gas analysis. The application of these power meters for LCLS-II and other X-ray FEL sources is discussed.

scholarly journals Optimization of X-ray emission from a laser-produced plasma in a narrow wavelength band

1992 ◽  
Vol 10 (4) ◽  
pp. 759-765 ◽  
Author(s):  
G. E. Van Dorssen ◽  
E. Louis ◽  
F. Bijkerk
Keyword(s):  
Power Density ◽  
Laser Power ◽  
Multilayer Coating ◽  
Target Surface ◽  
Laser Power Density ◽  
Strong Increase ◽  
Wavelength Band ◽  
Line Radiation ◽  
X Ray ◽  
Photoconductive Detector

The X-ray emission from laser-produced plasmas at an X-ray wavelength of approximately 10.4 nm was measured for Al and Gd target materials. The laser power density on the target surface was varied between 1.5 × 1010 and 3 × 1012 W/cm2 to obtain different electron temperatures. The output from the plasma was measured using an X-ray reflecting Pd-C multilayer coating as a wavelength-selective element and a diamond photoconductive detector. The emission at 10.4 nm is strongest at the low end of the power density range investigated. A strong increase is found for Al targets due to a contribution of line radiation, which is not present in the Gd plasmas. The measured conversion efficiency for Al plasmas was (4.5 ± 1)% in a 3% bandwidth at an X-ray wavelength of 10.4 nm.

Synchrotron-Based X-ray Microtomography Characterization of the Effect of Processing Variables on Porosity Formation in Laser Power-Bed Additive Manufacturing of Ti-6Al-4V

JOM ◽  
2017 ◽  
Vol 69 (3) ◽  
pp. 479-484 ◽  
Author(s):  
Ross Cunningham ◽  
Sneha P. Narra ◽  
Colt Montgomery ◽  
Jack Beuth ◽  
A. D. Rollett
Keyword(s):  
Additive Manufacturing ◽  
Laser Power ◽  
Porosity Formation ◽  
X Ray ◽  
Processing Variables

Determination of x-ray free electron laser power using a room-temperature calorimeter

Metrologia ◽  
2016 ◽  
Vol 53 (1) ◽  
pp. 98-102 ◽  
Author(s):  
T Tanaka ◽  
M Kato ◽  
N Saito ◽  
K Tono ◽  
M Yabashi ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Laser Power ◽  
Room Temperature ◽  
X Ray

Laser power and scanning speed influence on the microstructure, hardness, and slurry erosion performance of Colmonoy-5 claddings

2020 ◽  
Vol 234 (7) ◽  
pp. 947-961
Author(s):  
T Savanth ◽  
Jastej Singh ◽  
JS Gill
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Laser Processing ◽  
Laser Power ◽  
Erosive Wear ◽  
Scanning Speed ◽  
Processing Parameters ◽  
X Ray ◽  
High Scanning Speed ◽  
Scanning Electron

A 4kW Yb: YAG solid-state disc laser, with a four-way co-axial cladding head with powder feeding technique was employed to fabricate single-layer clads of Ni-based hardfacing alloy (Colmonoy-5) on medium carbon steel (ASME SA105) substrate by varying the laser processing parameters namely, beam power level (designated as low: 1200 W, medium: 1400 W, and high: 1600 W) and scanning speed (designated as low: 300 mm/min, medium: 400 mm/min, and high: 500mm/min). The laser clads were evaluated for their microstructural characteristics, microhardness, and slurry erosive wear performance with an aim to understand the effect of process parametric variations on their properties. Microstructural analyses of the clads were carried out using an optical microscope and a field-emission scanning electron microscope with attached energy-dispersive X-ray spectrometer supplemented by their Vickers microhardness testing and X-ray diffraction examination. The variation in laser processing parameters exerted a strong influence on the microstructural features of the clads in terms of γ-Ni dendrite size as well as morphology and distribution of various complex precipitates such as Cr-carbides and borides with relatively uniform distribution observed for the clads corresponding to low laser power and high scanning speed. The variation in laser power had relatively a greater influence on microhardness than the scanning speed variation. Micro-cutting, plastic deformation, crater formation besides ploughing away of the softer matrix were the typical fracture features associated with slurry eroded clads when examined under field-emission scanning electron microscope. Results of the slurry erosive wear tests showed that the clads pertaining to low laser power and high scanning speed exhibited superior wear resistance as compared to their counterparts.

Laser Recrystallization of InP Films on Oxidized Si Substrate

1985 ◽  
Vol 53 ◽  
Author(s):  
Li Xiqiang ◽  
Zhu Weiwen ◽  
Lin Chenglu ◽  
Wang Weiyuan ◽  
Tsou Shihchang
Keyword(s):  
Grain Size ◽  
Laser Power ◽  
Beam Diameter ◽  
Electrical Characteristics ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray ◽  
Si Substrates ◽  
Laser Recrystallization ◽  
Before And After

ABSTRACTThe InP films with thickness of 1-2 µm and resistivity of 10-10−3Ω-cm were sputtered on oxidized Si substrates heated at about 300°C to form as InP SOI. Using X-ray diffraction, ED, TEM, Hall and RBS, we have investigated the grain size, compositions, thermal stability and electrical characteristics of InP SOI before and after CW Ar+ laser recrystallization. The sputtered InP SOI films appear as polycrystalline and its grain size increases with increasing of irradiated laser power from 5.8 to 7.0 W at a beam diameter of 70 µm. After irradiation at 7 W the single crystal ED patterns are obtained, the mobility and carrier concentrations amount to 103cm2/Vs and 1017cm−3, respectively, and the compositions are stoichiometric.

scholarly journals The Effect of Laser Power on the Properties of M3B2-Type Boride-Based Cermet Coatings Prepared by Laser Cladding Synthesis

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1867 ◽  
Author(s):  
Zhaowei Hu ◽  
Wenge Li ◽  
Yuantao Zhao
Keyword(s):  
Laser Cladding ◽  
Laser Power ◽  
Chemical Properties ◽  
Scanning Speed ◽  
Carbon Steels ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
Cermet Coatings ◽  
X Ray ◽  
And Chemical Properties

Boride-based cermet can serve as a good protective coating for low-corrosion and wear-resistant materials, such as carbon steels, due to their mechanical and chemical properties. In this study, M3B2 (M: Mo, Ni, Fe, and Cr) boride-based cermet coatings were fabricated on Q235 steel with mixed powders of Mo, B, Ni60, and Cr by laser cladding synthesis, and the effects of laser power on the properties of the cermet layer were investigated. Three laser powers (2200, 2500, and 2800 W) were used at the same scanning speed. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analysis confirmed that all the coatings were composed of M3B2-type borides and {Fe, Ni} alloys. The micro-hardness, corrosion, and frictional experiments showed that the cermet coatings enhanced the corresponding performances of the Q235 steels at the three laser powers. However, the micro-hardness of the coatings decreased as the power increased, and the maximum micro-hardness value was 1166.3 HV (Vickers Hardness). The results of the corrosion and frictional experiments showed that the best performance was obtained at a laser power of 2500 W, followed by 2800 and 2200 W.

Bioactive Coating From White Portland Cement Deposited by Pulsed Laser Deposition

2017 ◽  
Author(s):  
Svitlana Fialkova ◽  
Sergey Yarmolenko ◽  
Jagannathan Sankar ◽  
Geoffrey Ndungu ◽  
Kevin Wilkinson
Keyword(s):  
Simulated Body Fluid ◽  
Portland Cement ◽  
Laser Power ◽  
Body Fluid ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray ◽  
Bioactive Coating ◽  
White Portland Cement ◽  
Deposited Films

Objective. We report the study of feasibility to produce the thing bioactive coating from experimental dental cement using pulsed laser deposition (PLD) technique. Methods. The targets for PLD system (disks 30 mm in diameter × 5 mm thick) were sintered from micronized powder of set Alborg White Portland cement (WPC). The parameters for sintering process were chosen based thermo-gravimetric analysis and differential scanning calorimetry (TGA/DSC). The coatings were deposited by PLD on silicon substrates. The effect of laser power on coating crystallinity and morphology was evaluated by scanning electron microscope (SEM) and X-ray diffraction (XRD). The material transfer from target to substrate were evaluated by X-ray fluorescence (XRF) and X-ray energy dispersive spectroscopy (EDS). The bioactivity of deposited films was evaluated by ability produce the hydroxyapatite (HA) layer on a surface of specimen immersed in a simulated body fluid (Dulbecco’s Phosphate-Buffered Saline (DPBS). The formation of hydroxyapatite was confirmed by SEM, X-ray energy dispersive spectroscopy (EDS), XRD and micro-Raman spectroscopy. The formation of HA was evaluated after 1, 3, 7, 14, and 21 days of immersion. Results. This study demonstrated that White Portland cement can be used as a target material for manufacturing of bio-functional coatings. The films deposited on Si substrates have mainly amorphous structure; the crystallinity of the film can be achieved by increasing the laser power. The biological performance of deposited films was tested by HA forming ability in simulated body fluid. The HA layer was formed on a coated surface after first day of immersion.

Laser-slicing at a low-emittance storage ring

2019 ◽  
Vol 26 (5) ◽  
pp. 1523-1538
Author(s):  
Simone Di Mitri ◽  
William Barletta ◽  
Anna Bianco ◽  
Ivan Cudin ◽  
Bruno Diviacco ◽  
...  
Keyword(s):  
Storage Ring ◽  
Laser Power ◽  
State Of The Art ◽  
Beam Emittance ◽  
X Ray ◽  
Average Laser Power ◽  
Spectral Separation ◽  
Order Of Magnitude ◽  
Transverse Gradient ◽  
Low Emittance

Laser-slicing at a diffraction-limited storage ring light source in the soft X-ray region is investigated with theoretical and numerical modelling. It turns out that the slicing efficiency is favoured by the ultra-low beam emittance, and that slicing can be implemented without interference to the standard multi-bunch operation. Spatial and spectral separation of the sub-picosecond radiation pulse from a hundreds of picosecond-long background is achieved by virtue of 1:1 imaging of the radiation source. The spectral separation is enhanced when the radiator is a transverse gradient undulator. The proposed configuration applied to the Elettra 2.0 six-bend achromatic lattice envisages total slicing efficiency as high as 10−7, one order of magnitude larger than the demonstrated state-of-the-art, at the expense of pulse durations as long as 0.4 ps FWHM and average laser power as high as ∼40 W.

scholarly journals Mechanical Properties of White Metal on SCM440 Alloy Steel by Laser Cladding Treatment

2021 ◽  
Vol 11 (6) ◽  
pp. 2836
Author(s):  
Jae-Il Jeong ◽  
Jong-Hyoung Kim ◽  
Si-Geun Choi ◽  
Young Tae Cho ◽  
Chan-Kyu Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Coefficient ◽  
Alloy Steel ◽  
Laser Cladding ◽  
Laser Power ◽  
Centrifugal Casting ◽  
Operating Conditions ◽  
White Metal ◽  
X Ray ◽  
Friction Testing

The bearing is a machine element that plays an important role in rotating the shaft of a machine while supporting its weight and load. Numerous bearings have been developed to improve durability and life, depending on the functions and operating conditions in which they are desired. White metal is one of method to improve durability that is soft and bonded to the inner surface of the bearing to protect the bearing shaft. Currently, the centrifugal casting process is used as a white metal lamination method, but it involves problems such as long processing times, high defect rates and harmful health effects. In this paper, a laser cladding treatment is applied to bond powdered white metal to SCM440 alloy steel, which is used as bearing material in terms of replacing the risks of a centrifugal process. In order to understand whether laser cladding is a suitable process, this paper compares the mechanical properties of white metal produced on SCM440 alloy steel by centrifugal casting and the laser cladding process. The laser power, powder feed rate and laser head speed factors are varied to understand the mechanical properties and measure the hardness using micro Vickers and conduct field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and friction testing to understand the mechanical properties and surface characteristics. Based on the results, the hardness values of the cladding (white metal) layer ranged between 24 and 26 HV in both the centrifugal casting and laser cladding methods. However, the hardness of the white metal produced by laser cladding at about a depth of 0.1 mm rose rapidly in the cladding process, forming a heat-affected zone (HAZ) with an average hardness value of 200 HV at a laser power of 1.1 kW, 325 HV at 1.3 kW and 430 HV at 1.5 kW. The surface friction testing results revealed no significant differences in the friction coefficient between the centrifugal casting and laser cladding methods, which allows the assumption that the processing method does not significantly influence the friction coefficient.

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