Rf Gun Photo-Emission Model for Metal Cathodes Including Time Dependent Emission

Schmerge, John; Clendenin, J.E.; Dowell, D.H.; Gierman, S.M.

doi:10.1142/9789812772176_0028

Cited by 4 publications

(3 citation statements)

References 2 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A new simulation tool to fully model the dynamics of the beam and the diffraction from a target with known properties (as for example a thin Al foil) is being developed to allow a direct comparison of the diffraction patterns. Furthermore, considering different magnetic field configurations and exploring the best compromise between quantum efficiency and thermal emittance for the cathode/laser wavelength choice (Schmerge et al, 2007) could bring other significant improvements.…”

Section: Discussionmentioning

confidence: 99%

Novel Radio-Frequency Gun Structures for Ultrafast Relativistic Electron Diffraction

et al. 2009

View full text Add to dashboard Cite

Radio-frequency (RF) photoinjector-based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe structural changes at the atomic scale with sub-100 fs temporal resolution in a single shot. We analyze the limitations on the temporal and spatial resolution of this technique considering the operating parameters of a standard 1.6 cell RF gun (which is the RF photoinjector used for the first experimental tests of relativistic UED at Stanford Linear Accelerator Center; University of California, Los Angeles; Brookhaven National Laboratory), and study the possibility of employing novel RF structures to circumvent some of these limits.

show abstract

Section: Discussionmentioning

confidence: 99%

Novel Radio-Frequency Gun Structures for Ultrafast Relativistic Electron Diffraction

et al. 2009

View full text Add to dashboard Cite

show abstract

“…The cathode QE is affected by two more specific mechanisms. The first one concerns the modification of the work function due to the strong electromagnetic fields applied on the cathode [38][39]. The total electric field at the cathode is given by the RF field in the gun, E rf , and by the space charge field of the bunch, E sc .…”

Section: Source Limited Emissionmentioning

confidence: 99%

Modeling and simulation of RF photoinjectors for coherent light sources

Chen

Krasilnikov

Stephan

et al. 2018

Nuclear Instruments and Methods in Physics Research Section A:

View full text Add to dashboard Cite

We propose a three-dimensional fully electromagnetic numerical approach for the simulation of RF photoinjectors for coherent light sources. The basic idea consists in incorporating a selfconsistent photoemission model within a particle tracking code. The generation of electron beams in the injector is determined by the quantum efficiency (QE) of the cathode, the intensity profile of the driving laser as well as by the accelerating field and magnetic focusing conditions in the gun. The total charge emitted during an emission cycle can be limited by the space charge field at the cathode. Furthermore, the time and space dependent electromagnetic field at the cathode may induce a transient modulation of the QE due to surface barrier reduction of the emitting layer. In our modeling approach, all these effects are taken into account. The beam particles are generated dynamically according to the local QE of the cathode and the time dependent laser intensity profile. For the beam dynamics, a tracking code based on the Lienard-Wiechert retarded field formalism is employed. This code provides the single particle trajectories as well as the transient space charge field distribution at the cathode. As an application, the PITZ injector is considered. Extensive electron bunch emission simulations are carried out for different operation conditions of the injector, in the source limited as well as in the space charge limited emission regime. In both cases, fairly good agreement between measurements and simulations is obtained.

show abstract

“…where QE i is the quantum efficiency of copper at wavelength i . Schmerge et al (2007) state that as the wavelength of light decreases, the quantum efficiency of copper increases. The estimated quantum efficiency of copper at UV wavelengths from 116 to 260 nm varies from 10 Ϫ2 to 10 Ϫ3 .…”

Section: Ultraviolet Radiation Measurementsmentioning

confidence: 99%

Photocurrents obtained from a triple planar probe sensor for in situ extreme ultraviolet (EUV) radiation measurements on low Earth orbiting CubeSats

Ayeleso

Zyl²

2016

JEDT

View full text Add to dashboard Cite

Purpose In the Earth’s upper atmosphere, damage to satellite electronics is caused by exposure to extreme ultraviolet (EUV) radiation. One particular region where this type of radiation occurs is the South Atlantic Magnetic Anomaly region. As a result, there is a need to design and develop a sensor which could be used to investigate the flux and energy levels of radiation in this region. To do so, the aim of this study is to characterise the sensor and its electric response to typical EUV radiation levels based on the photoelectric effect principle. Design/methodology/approach For this purpose, a copper plate planar sensor prototype with dimensions that fit on the sides of a one-unit (1U) CubeSat was constructed. The sensor prototype was placed in a vacuum chamber and was subjected to continuous radiation from a vacuum ultraviolet deuterium light source at test facilities available in the Western Cape region (South Africa). Subsequently, the terminal voltage of the sensor was measured and compared with theory. Findings The measured time-averaged terminal voltages indicate the generation of photocurrents of the order of 1 μA, which is consistent with theory. Originality/value Conclusively, these results validate the measurement approach and operation of the sensor, which can be used to design a 1U CubeSat sensor that measures EUV radiation in low Earth orbit.

show abstract

Rf Gun Photo-Emission Model for Metal Cathodes Including Time Dependent Emission

Cited by 4 publications

References 2 publications

Novel Radio-Frequency Gun Structures for Ultrafast Relativistic Electron Diffraction

Novel Radio-Frequency Gun Structures for Ultrafast Relativistic Electron Diffraction

Modeling and simulation of RF photoinjectors for coherent light sources

Photocurrents obtained from a triple planar probe sensor for in situ extreme ultraviolet (EUV) radiation measurements on low Earth orbiting CubeSats

Contact Info

Product

Resources

About