Assessment of log‐based fingerprinting system of Mobius3D with Elekta linear accelerators

Generation of few-cycle optical pulses in free-electron laser (FEL) oscillators has been experimentally demonstrated in FEL facilities based on normal-conducting and superconducting linear accelerators. Analytical and numerical studies have revealed that the few-cycle FEL lasing can be explained in the frame of superradiance, cooperative emission from self-bunched systems. In the present paper, we review historical remarks of superradiance FEL experiments in short-pulse FEL oscillators with emphasis on the few-cycle pulse generation and discuss the application of the few-cycle FEL pulses to the scheme of FEL-HHG, utilization of infrared FEL pulses to drive high-harmonic generation (HHG) from gas and solid targets. The FEL-HHG enables one to explore ultrafast science with attosecond ultraviolet and X-ray pulses with a MHz repetition rate, which is difficult with HHG driven by solid-state lasers. A research program has been launched to develop technologies for the FEL-HHG and to conduct a proof-of-concept experiment of FEL-HHG.

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Space charge equilibrium and beam current limitations in ion linear accelerators

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment ◽

10.1016/0168-9002(94)90969-5 ◽

1994 ◽

Vol 345 (1) ◽

pp. 43-45

Author(s):

S.A. Minaev

Keyword(s):

Space Charge ◽

Beam Current ◽

Linear Accelerators ◽

Charge Equilibrium

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Development and characterization of Nb3Sn/Al2O3 superconducting multilayers for particle accelerators

Scientific Reports ◽

10.1038/s41598-021-87119-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chris Sundahl ◽

Junki Makita ◽

Paul B. Welander ◽

Yi-Feng Su ◽

Fumitake Kametani ◽

...

Keyword(s):

High Performance ◽

High Energy ◽

Particle Accelerators ◽

Quality Factors ◽

Critical Fields ◽

Linear Accelerators ◽

Cross Sectional ◽

Low Field ◽

Superconducting Radio Frequency

AbstractSuperconducting radio-frequency (SRF) resonator cavities provide extremely high quality factors > 1010 at 1–2 GHz and 2 K in large linear accelerators of high-energy particles. The maximum accelerating field of SRF cavities is limited by penetration of vortices into the superconductor. Present state-of-the-art Nb cavities can withstand up to 50 MV/m accelerating gradients and magnetic fields of 200–240 mT which destroy the low-dissipative Meissner state. Achieving higher accelerating gradients requires superconductors with higher thermodynamic critical fields, of which Nb3Sn has emerged as a leading material for the next generation accelerators. To overcome the problem of low vortex penetration field in Nb3Sn, it has been proposed to coat Nb cavities with thin film Nb3Sn multilayers with dielectric interlayers. Here, we report the growth and multi-technique characterization of stoichiometric Nb3Sn/Al2O3 multilayers with good superconducting and RF properties. We developed an adsorption-controlled growth process by co-sputtering Nb and Sn at high temperatures with a high overpressure of Sn. The cross-sectional scanning electron transmission microscope images show no interdiffusion between Al2O3 and Nb3Sn. Low-field RF measurements suggest that our multilayers have quality factor comparable with cavity-grade Nb at 4.2 K. These results provide a materials platform for the development and optimization of high-performance SIS multilayers which could overcome the intrinsic limits of the Nb cavity technology.

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Synchrotron X-ray induced acoustic imaging

Scientific Reports ◽

10.1038/s41598-021-83604-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Seongwook Choi ◽

Eun-Yeong Park ◽

Sinyoung Park ◽

Jong Hyun Kim ◽

Chulhong Kim

Keyword(s):

Acoustic Imaging ◽

Signal Frequency ◽

X Rays ◽

Repetition Period ◽

Linear Accelerators ◽

X Ray ◽

X Ray Computed ◽

Medical Linear Accelerators ◽

Ionizing Radiation Exposure ◽

X Ray Absorption

AbstractX-ray induced acoustic imaging (XAI) is an emerging biomedical imaging technique that can visualize X-ray absorption contrast at ultrasound resolution with less ionizing radiation exposure than conventional X-ray computed tomography. So far, medical linear accelerators or industrial portable X-ray tubes have been explored as X-ray excitation sources for XAI. Here, we demonstrate the first feasible synchrotron XAI (sXAI). The synchrotron generates X-rays, with a dominant energy of 4 to 30 keV, a pulse-width of 30 ps, a pulse-repetition period of 2 ns, and a bunch-repetition period of 940 ns. The X-ray induced acoustic (XA) signals are processed in the Fourier domain by matching the signal frequency with the bunch-repetition frequency. We successfully obtained two-dimensional XA images of various lead targets. This novel sXAI tool could complement conventional synchrotron applications.

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Translational Research in FLASH Radiotherapy—From Radiobiological Mechanisms to In Vivo Results

Biomedicines ◽

10.3390/biomedicines9020181 ◽

2021 ◽

Vol 9 (2) ◽

pp. 181

Author(s):

Loredana G. Marcu ◽

Eva Bezak ◽

Dylan D. Peukert ◽

Puthenparampil Wilson

Keyword(s):

Dose Rate ◽

High Dose Rate ◽

Current Status ◽

Therapeutic Window ◽

High Dose ◽

Linear Accelerators ◽

Radiation Delivery ◽

Tissue Sparing

FLASH radiotherapy, or the administration of ultra-high dose rate radiotherapy, is a new radiation delivery method that aims to widen the therapeutic window in radiotherapy. Thus far, most in vitro and in vivo results show a real potential of FLASH to offer superior normal tissue sparing compared to conventionally delivered radiation. While there are several postulations behind the differential behaviour among normal and cancer cells under FLASH, the full spectra of radiobiological mechanisms are yet to be clarified. Currently the number of devices delivering FLASH dose rate is few and is mainly limited to experimental and modified linear accelerators. Nevertheless, FLASH research is increasing with new developments in all the main areas: radiobiology, technology and clinical research. This paper presents the current status of FLASH radiotherapy with the aforementioned aspects in mind, but also to highlight the existing challenges and future prospects to overcome them.

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