Monte Carlo simulations of secondary electron emission from CsI, induced by 1–10 keV x rays and electrons

Akkerman, A.; Gibrekhterman, A.; Breskin, A.; Chechik, R.

doi:10.1063/1.351984

Cited by 60 publications

(16 citation statements)

References 29 publications

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“…Fraser 23,24 examined the total yield and pulsed quantum efficiency with respect to photon incidence angle and energy, and presented a model describing the dynamics in terms of averaged parameters for the SE creation energy and their inelastic mean free path. Boutboul et al [25][26][27] introduced a model in which a more rigorous treatment of the electron-phonon scattering was implemented for CsI, but obtained an energy spread for the SE deviating from Henke's experiments. This discrepancy was claimed to arise from the lack of treatment of plasmons in their model.…”

Section: Introductionmentioning

confidence: 99%

Secondary Electron Cascade Dynamics in KI and CsI

Ortiz

Caleman

2007

J. Phys. Chem. C

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We present a study of the characteristics of secondary electron cascades in two photocathode materials, KI and CsI. To do so, we have employed a model that enables us to explicitly follow the electron trajectories once the dielectric properties have been derived semiempirically from the energy loss function. Furthermore, we introduce a modification to the model by which the energy loss function is calculated in a first-principle manner using the GW approximation for the self-energy of the electrons. We find good agreement between the two approaches. Our results show comparable saturation times and secondary electron yields for the cascades in the two materials, and a narrower electron energy distribution (51%) for KI compared to that for CsI.

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Section: Introductionmentioning

confidence: 99%

Secondary Electron Cascade Dynamics in KI and CsI

Ortiz

Caleman

2007

J. Phys. Chem. C

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“…This model of SE production requires two empirical parameters: the energy to produce a SE and its escape depth (18.5 eV/SE and 200 Å escape depth) [7]. These have been obtained by comparison to the results of Akkerman and co-workers [8].…”

Section: Performance Optimizationmentioning

confidence: 99%

A Gd-based gaseous electron multiplier detector for neutron scattering applications

DiJulio

Hawari

Berliner

2007

Nuclear Instruments and Methods in Physics Research Section A:

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The optimum configuration of a Gaseous Electron Multiplier (GEM) neutron detector using a CsI-Gd-Kapton-Gd-CsI neutron converter is investigated using Monte-Carlo simulations. Neutrons absorbed in the converter produce secondary electrons that are emitted from the CsI layers. The detector can be assembled from multiple modules where each module consists of the neutron converter, several cascaded GEMs and anode pickup plates on both sides. Position sensitive anodes and localization electronics are then used to detect, timestamp and record the resulting signal. For a single GEM module, the performance can be assessed by estimating the secondary electron (SE) leakage from the converter sandwich. The simulations show that the optimum for a single module, double-sided detector would have a neutron converter composed of 0.1 mm CsI on top of 3 mm Gd plated on each side of a 7.5 mm thick Kapton foil. This detector would have a SE yield of approximately 0.6 SE/neutron and neutron absorption of 60%. Significant enhancements of the SE yield can be obtained for detectors composed of multiple modules with thinner Gd converters. The multi-module design allows for enhanced SE leakage from each converter while maintaining the high neutron absorption efficiency of thicker converters and dividing the detector count rate among multiple sets of decoding electronics. r

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“…Electron transmission of CsI turned out to be higher compared to that of NaI, in accordance with theoretical estimations. 13 The protection capability of CsI films was found to be comparable with that of NaI, for an equal postcoating attenuation of the photoyield and for oxygen pressures below 10 Ϫ2 Torr ͑see sures it is appreciably smaller compared to NaI.…”

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confidence: 93%

“…The attenuation of the photoemission for film thicknesses above 15 Å is exponential, with an attenuation slope depending on the wavelength. Generally, the attenuation of the photoemission is caused by quasielastic and inelastic photoelectron scattering within the coating film, on acoustic and optical phonons 13 and on structural defects. In addition, a modification of the surface potential barrier due to a formation of a dipole layer at the Cs 3 Sb/NaI interface further attenuates the emission yield.…”

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confidence: 99%