Engineering topics

Tiwari, Ganesh

Publications and source records attributed to Tiwari, Ganesh.

5 records

DOE OSTI2024

EUV FEL light source based on energy recovery linac with on-orbit laser plasma injection

We report on a week-long study of a conceptual design of EUV FEL light source based on an energy recovery linac with on-orbit laser plasma accelerator injection scheme. We carried out this study during USPAS Summer 2023 session of Unifying Physics of Accelerators, Lasers and Plasma applying the art of inventiveness TRIZ. An ultrashort Ti-sapphire laser accelerates electron beams from a gas target with mean energy of 20 MeV, which are then ramped up to 1 GeV in a five-turn scheme with a series of fixed field alternating magnets and two superconducting RF cavities (100 MeV per cavity per turn). The electron beam is then bypassed to an undulator line optimized to generate EUV light of 13.5 nm at kW level in a single pass.

43 PARTICLE ACCELERATORS↗

DOE OSTI2024

Power loss analysis for optical cavity of X-ray free-electron laser oscillator at 10 KeV

We investigate properties of optical elements in the optical cavity of an X-ray free electron laser oscillator with emphasis on power loss of a monochromatic Gaussian radiation beam upon passing through them using analytical and numerical approaches. Here we assume the optical cavity comprises of refractive lenses and Bragg crystals exploiting symmetric Bragg scattering. For lens, we include the focusing and curvature effects while we include the angular filtering due to finite Darwin width of Bragg crystals. Our results indicate feasibility of Xray power outcoupling in the range of 0.5-28 % with intra-cavity reflectivity of 67-95 % at 10.321 KeV.

43 PARTICLE ACCELERATORS↗

DOE OSTI2024

Power density calculation of spontaneous radiation emission from a finite emittance electron beam in planar undulators

We extend the angular power density formulae for spontaneous radiation emission from planar undulators to include finite emittance and angular misalignment of the electron beam. Then we calculate and compare power densities estimated from integral approach with Gaussian beam distribution and summation approach with macro-particle allocation covering particle beam phase space. After showing that both approaches converge to each other, we apply the macro-particle approach to study power absorbed and transmitted by various apertures at front end of 9-ID beamline at National Synchrotron Light Source-II for misaligned electron beam. Our analysis indicate that the electron beam misalignment could lead to unwarranted power deposition at tighter apertures that would have been otherwise difficult to account for during the aperture design/choice process.

43 PARTICLE ACCELERATORS↗

DOE OSTI2023

Compound refractive lenses for X-rays

Compund refractive lenses are primarly used for focusing and transport of X-rays and for forming a stable optical cavity and mode matching to maximize FEL gain [1]. In this report, we cover focusing behavior and effects of curvature of compound refractive lenses on X-ray beam propagation. Our analysis is limited to X-ray beams with transverse Gaussian profile and is thus purely analytical in nature.

43 PARTICLE ACCELERATORS↗

DOE OSTI2023

Two-beam Bragg diffraction, filtering, and delays

We summarize transmission and reflection amplitudes of Bragg-crystals based on two-beam Bragg diffraction theory. Then, we consider a specific case of infinitely thick and symmetrical Bragg-crystal and its reflective properties in spectral and angular domain. We obtain analytical expressions for filtering width and respective delay amplitudes, temporal delay from spectral phase shift and spatial displacement from angular phase shift.

43 PARTICLE ACCELERATORS↗