相关论文: Observation Of Repetition-Rate Dependent Emission …
Un-gated thermionic cathode RF guns are well known as a robust source of electrons for many accelerator applications. These sources are in principle scalable to high currents without degradation of the transverse emittance due to control…
Advances in electron beam technology have been central to creating the current generation of x-ray free electron lasers and ultra-fast electron microscopes. These once exotic devices have become essential tools for basic research and…
Undesirable electron field emission (a.k.a. dark current) in high gradient RF photocathode guns deteriorates the quality of photoemission current and limits the operational gradient. To improve the understanding of dark current emission, a…
It is currently not known if repeating fast radio bursts (FRBs) are fundamentally different from those that have not been seen to repeat. One striking difference between repeaters and apparent non-repeaters in the CHIME sample is that the…
We discuss some of the claims that have been made regarding the statistics of fast radio bursts (FRBs). In an earlier paper \citep{2015arXiv150505535C} we conjectured that flicker noise associated with FRB repetition could show up in…
A high-brilliance ($\sim10^{24}$~photon.s$^{-1}$.mm$^{-2}$.mrd$^{-2}$/0.1\%) gamma-ray source experiment is currently being planned at Fermilab ($E_\gamma\simeq 1.1$~MeV)~[1]. The source implements a high-repetition-rate inverse Compton…
We present a novel concept for the generation of gigahertz repetition rate high brightness electron bunches. A custom design 100 kV thermionic gun provides a continuous electron beam, with the current determined by the filament size and…
The production of electron bunches with low transverse emittance approaches the thermal emittance of the photocathode as various aberrations are corrected. Recently, the coupled transverse dynamics aberration was theoretically identified as…
The origin of fast radio bursts (FRBs), highly energetic, millisecond-duration radio pulses originating from beyond our galaxy, remains unknown. Observationally, FRBs are classified as non-repeating or repeating, however, this…
Field emission or dark current from RF electron guns is problematic for accelerators for several reasons, and can be more difficult to predict, measure and understand, compared to the main beam. The work presented here is a study of the…
The physical origin of fast radio bursts (FRBs) is still unknown. Multiwavelength and polarization observations of an FRB source would be helpful to diagnose its progenitor and environment. So far only the first repeating source FRB 121102…
To make full use of photocathode material and improve its quantum efficiency lifetime, it can be necessary to operate laser away from the cathode center in photoinjectors. In RF guns, the off-axis emitted beam will see a time-dependent RF…
We present design and simulation results on the electron source for 2856 MHz technological electron linac. This device is a combination of an RF gun and a DC diode gun. The designed gun consists of a thermionic cathode, which is mounted on…
We describe use of the Advanced Photon Source (APS) rf thermionic gun, alpha magnet beamline, and linac to produce a stable high-brightness beam in excess of 100 amperes peak current with normalized emittance of 10 pi mm-mrad. To obtain…
The advent of high-average-power, ultrafast ytterbium-based lasers allows us to generate laser filaments at repetition rates ranging from 10s of kHz up to 100s of kHz. At such high repetition rates, the inter-pulse time lies below the time…
Superconducting radio-frequency (SRF) guns are promising candidates to deliver high brightness continuous-wave (CW) electron beams for new generations of coherent linac light sources, ultrafast electron diffractions, MeV pulsed beam…
Recently, some fast radio burst (FRB) repeaters were reported to exhibit complex, diverse variations of Faraday rotation measures (RMs), which implies that they are surrounded by an inhomogeneous, dynamically evolving, magnetized…
The repetition rate of a Kerr comb comprising a single soliton in an anomalous dispersion silicon nitride microcavity is measured as a function of pump frequency tuning. The contributions from the Raman soliton self-frequency shift (SSFS)…
In conjunction with efforts to predict residual radiation levels in the Fermilab Main Injector, measurements of residual radiation were correlated with the time history of losses. Detailed examination suggested that the list of radioactive…
KEK-ATF is studying the low-emittance multi-bunch electron beam for the future linear collider. In ATF, thermionic gun is used to generate 20 bunches electron beam with the bunch spacing of 2.8 ns. Due to a distortion of the gun emission…