Terms Of Beam Size Research Articles

Propagation of hyperbolic sinusoidal Gaussian beam in jet engine induced turbulence

This paper investigates beam evolution and beam sizes variation of hyperbolic sinusoidal Gaussian (HSG) beam propagating in jet engine exhaust-induced turbulence. We find the received field by solving Huygens-Fresnel integral with a relevant power spectrum. Our results reveal that HSG loses its initial profile until 100 m. Besides, beam with low displacement parameter value is more resistive against turbulence. In terms of beam size, beams with low Gaussian source size expand less as compared to the beams with larger Gaussian source size. In the light of our findings, optical systems in aircrafts like directed infrared counter measure (DIRCM) and laser designators can be developed.

Characterization of the PTB ultra-high pulse dose rate reference electron beam

Purpose. This investigation aims to present the characterisation and optimisation of an ultra-high pulse dose rate (UHPDR) electron beam at the PTB facility in Germany. A Monte Carlo beam model has been developed for dosimetry study for future investigation in FLASH radiotherapy and will be presented. Material and methods. The 20 MeV electron beams generated by the research linear accelerator has been characterised both in-beamline with profile monitors and magnet spectrometer, and in-water with a diamond detector prototype. The Monte Carlo model has been used to investigate six different setups to enable different dose per pulse (DPP) ranges and beam sizes in water. The properties of the electron radiation field in water have also been characterised in terms of beam size, quality specifier R 50 and flatness. The beam stability has also been studied. Results. The difference between the Monte-Carlo simulated and measured R 50 was smaller than 0.5 mm. The simulated beam sizes agreed with the measured ones within 2 mm. Two suitable setups have been identified for delivering reference UHPDR electron beams. The first one is characterised by a SSD of 70 cm, while in the second one an SSD of 90 cm is used in combination with a 2 mm aluminium scattering plates. The two set-ups are quick and simple to install and enable an expected overall DPP range from 0.13 Gy up to 6.7 Gy per pulse. Conclusion. The electron beams generated by the PTB research accelerator have shown to be stable throughout the four-months length of this investigation. The Monte Carlo models have shown to be in good agreement for beam size and depth dose and within 1% for the beam flatness. The diamond detector prototype has shown to be a promising tool to be used for relative measurements in UHPDR electron beams.

Characterization and optimization of ultra slow muon beam at J-PARC/MUSE: A simulation study

Abstract We have been developing an ultra slow muon microscope on the Super-omega muon beamline, called U-line, at the Muon Science Establishment (MUSE), Japan Proton Accelerator Research Complex (J-PARC), Japan. This development is expected to aid studies on nanoscience and three-dimensional visualization of small samples. During commissioning of the ultra slow muon beam, we performed Monte Carlo simulations, the results of which pointed out the significant effect of a stray magnetic field at the muonium chamber on the beam profile at sample position. To minimize this effect, we steered the beam using imbalance tuning of electric quadrupoles . This paper presents the simulation study of beam transportation, optimization, and characterization in terms of beam size, time, and energy distribution at sample position in one of the experimental areas, namely, U1A.

Resonant scattering and diffraction beamline P09 at PETRA III

The resonant scattering and diffraction beamline P09 at PETRA III is designed for X-ray experiments requiring small beams, energy tunability, variable polarization and high photon flux. It is highly flexible in terms of beam size and offers full higher harmonic suppression. A state-of-the-art double phase-retarder set-up provides variable linear or circular polarization. A high-precision Psi-diffractometer and a heavy-load diffractometer in horizontal Psi-geometry allow the accommodation of a wide variety of sample environments. A 14 T cryo-magnet is available for scattering experiments in magnetic fields.

Enhanced failure of ceramics irradiated by combined pulse and c.w. lasers

Several ceramic materials were subjected to the combined irradiation of a 1.06μ pulse and a 10.6μ continuous wave (c.w.) laser. The duration of c.w. irradiation required to cause failure from the combined exposure is compared to that from c.w. irradiation alone. For example, thin Pyroceram and soda-lime glass plates burned through when exposed to the c.w. laser followed by the single pulse laser, in about one half the time required to cause fracture during exposure to the c.w. laser alone. Also, enhanced catastrophic fracture of thick soda-lime glass plates resulted when the c.w. irradiation followed the pulse within 0.3 sec. Finally, the effects of the combined pulse and c.w. exposure are compared with the effects of single or multiple pulses, and the apparent enhancement is discussed in terms of beam size and power.