Broadened Energy Distributions in Electron Beams

Zimmermann, Bodo

doi:10.1016/s0065-2539(08)61093-8

Cited by 52 publications

(16 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In case ͑a͒ the cathode is most retracted from the anode, the total emission is very low, and the local repulsive field is rather weak. 14 As the cathode is further moved forward, in case ͑d͒, the emitting surface is greatly exposed to the anode voltage; the diminishing diverging fields account for the shortest imaging length in the four cases. A real crossover is formed in the gun.…”

Section: New Emission Modelmentioning

confidence: 98%

Emission optics of the Steigerwald-type electron gun

Ruan

Fink

1999

Review of Scientific Instruments

View full text Add to dashboard Cite

The emission properties of a Steigerwald-type electron gun are reexamined. Several optical parameters were experimentally determined, and they indicate that the original telefocus mechanism proposed by Steigerwald in 1949 needs to be revised. ''Remote focusing'' is found to be nonexistent in most of the telefocus electron guns deployed in high-energy electron scattering experiments. Instead, almost parallel beams with variable beam diameters were found. The physical mechanism responsible for producing a very narrow, monochromatic, and highly collimated beam without limiting apertures is explained in this article with supporting evidences from measurements. We think the new emission model proposed here can help new types of electron or ion gun designs and applications using electron gun in electron optical systems.

show abstract

Section: New Emission Modelmentioning

confidence: 98%

Emission optics of the Steigerwald-type electron gun

Ruan

Fink

1999

Review of Scientific Instruments

View full text Add to dashboard Cite

show abstract

“…Therefore, a process which can be described as the opposite of the Boersch effect can occur, i.e., a relaxation of kinetic energy from the longitudinal to the transverse direction. However, ions are usually accelerated to 30 keV in FIBs, which decreases the longitudinal temperature of the beam 22 with a factor 10 6 . Therefore, the effects of this process are expected to be minor.…”

Section: Disorder-induced Heatingmentioning

confidence: 99%

Performance predictions of a focused ion beam from a laser cooled and compressed atomic beam

Haaf

Wouters

Geer

et al. 2014

Journal of Applied Physics

View full text Add to dashboard Cite

Focused ion beams are indispensable tools in the semiconductor industry because of their ability to image and modify structures at the nanometer length scale. Here we report on performance predictions of a new type of focused ion beam based on photo-ionization of a laser cooled and compressed atomic beam. Particle tracing simulations are performed to investigate the effects of disorder-induced heating after ionization in a large electric field. They lead to a constraint on this electric field strength which is used as input for an analytical model which predicts the minimum attainable spot size as a function of amongst others the flux density of the atomic beam, the temperature of this beam and the total current. At low currents (I < 10 pA) the spot size will be limited by a combination of spherical aberration and brightness, while at higher currents this is a combination of chromatic aberration and brightness. It is expected that a nanometer size spot is possible at a current of 1 pA. The analytical model was verified with particle tracing simulations of a complete focused ion beam setup. A genetic algorithm was used to find the optimum acceleration electric field as a function of the current. At low currents the result agrees well with the analytical model while at higher currents the spot sizes found are even lower due to effects that are not taken into account in the analytical model.

show abstract

“…Its energy distribution is not necessarily a Maxwellian because it depends on a variety of factors, such as filament geometry, space charge, the work function of the material, crystalline structure of the filament and the Boersch effect (Boersch, 1954;Loeffler, 1969;Zimmermann, 1970;Ditchfield and Whelan, 1977;Rose and Spehr, 1980). Zimmermann (1970) and Rose and Spehr (1980) showed that the Coulomb interaction between the individual electrons are primarily responsible for the large energy spread in an electron beam of high current density. It is usually assumed that the electrons emitted from the cathode are in thermal equilibrium having a Maxwellian distribution of velocity in any direction.…”

Section: Thermo-ionic Emitter (Lab 6 )mentioning

confidence: 99%

Low voltage TEM: Influences on electron energy loss spectrometry experiments

Stöger-Pollach

2010

Micron

View full text Add to dashboard Cite

Broadened Energy Distributions in Electron Beams

Cited by 52 publications

References 28 publications

Emission optics of the Steigerwald-type electron gun

Emission optics of the Steigerwald-type electron gun

Performance predictions of a focused ion beam from a laser cooled and compressed atomic beam

Low voltage TEM: Influences on electron energy loss spectrometry experiments

Contact Info

Product

Resources

About