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Naranjo, Brian

Publications and source records attributed to Naranjo, Brian.

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Hard X-ray inverse Compton scattering at photon energy of 87.5 keV

Abstract Production of hard X-ray via inverse Compton scattering at photon energies below 100 keV range aimed at potential applications in medicine and material research is reported. Experiments have been performed at the Brookhaven National Laboratory, Accelerator Test Facility, employing the counter collision of a 70 MeV, 0.3 nC electron beam with a near infra-red Nd: YAG laser (1064 nm wavelength) pulse containing ~ 100 mJ in a single shot basis. The radiation distribution of the scattered photon beam is assessed to be sufficiently quasi monochromatic to produce clear contrast from the Au K - edge at 80.7 keV.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Suppression of Deflecting Forces in Planar-Symmetric Dielectric Wakefield Accelerating Structures with Elliptical Bunches

Wakefield based accelerators capable of accelerating gradients two orders of magnitude higher than present accelerators offer a path to compact high energy physics instruments and light sources. However, for high gradient accelerators, beam instabilities driven by commensurately high transverse wakefields limit beam quality. It has been previously theoretically shown that transverse wakefields can be reduced by elliptically shaping the transverse sizes of beams in dielectric structures with planar symmetry. We report here experimental measurements that demonstrate reduced transverse wakefields for elliptical beams in planar symmetric structures which are consistent with theoretical models. Furthermore, these results may enable the design of gigavolt-per-meter gradient wakefield based accelerators that produce and stably accelerate high quality beams.

47 OTHER INSTRUMENTATION↗
DOE OSTI2019

Conductivity Induced by High-Field Terahertz Waves in Dielectric Material

An intense, sub-picosecond, relativistic electron beam traversing a dielectric lined waveguide generates very large amplitude electric fields at terahertz (THz) frequencies through the wakefield mechanism. In recent work employing this technique to accelerate charged particles, generation of high-power, narrowband THz radiation was demonstrated [ ]. The radiated waves contain fields with measured amplitude exceeding 2 GV/m, orders of magnitude greater than those available by other THz generation techniques at narrow bandwidth. For fields approaching the GV/m level, a strong damping has been observed in SiO 2 . This wave attenuation with onset near 850 MV/m, is consistent with changes to the conductivity of the dielectric lining and is characterized by a distinctive latching mechanism that is reversible on longer time scales. Here, we describe the detailed measurements that serve to clarify the underlying physical mechanisms leading to strong field-induced damping of THz radiation ( h ω = 1.59 meV, f = 0.38 THz) in SiO 2 , a bulk, wide band-gap (8.9 eV) dielectric.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Dielectric laser accelerators

The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. In this work, the physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV/m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

43 PARTICLE ACCELERATORS↗