A compton spectrometer to monitor the ELI-NP gamma beam energy

The ELI-NP (Extreme Light Infrastructure-Nuclear Physics) facility, currently under construction near Bucharest (Romania), is the pillar of the project ELI dedicated to the generation of high-brilliance gamma beams and high-power laser pulses that will be used for frontier research in nuclear physics. To develop an experimental program at the frontiers of the present-day knowledge, two pieces of equipment will be deployed at ELI-NP: a high power laser system consisting of two 10 PW lasers and a high brilliance gamma beam system. The ELI-NP Gamma beam system will deliver an intense gamma beam with unprecedented specifications in terms of photon flux, brilliance and energy bandwidth in an energy range from 0.2 to 20 MeV. Such a gamma beam requires special devices and techniques to measure and monitor the beam parameters during the commissioning and the operational phase. To accomplish this task, the Gamma Beam Characterization System, equipped with four elements, was developed: a Compton spectrometer (CSPEC), to measure and monitor the photon energy spectrum; a nuclear resonant scattering system (NRSS), for absolute beam energy calibration and inter-calibration of the other detectors; a beam profile imager (GPI) to be used for alignment and diagnostics purposes; and finally a sampling calorimeter (GCAL), for a fast combined measurement of the beam average energy and intensity. The combination of the measurements performed by GCAL and CSPEC allows fully characterizing the gamma beam energy distribution and intensity with a precision at the level of few per mill, enough to demonstrate the fulfillment of the required parameters. This article presents an overview of the gamma beam characterization system with focus on these two detectors, which were designed, assembled and are currently under test at INFN-Firenze. The layout and the working principle of the four devices is described, as well as some of the main results of detector tests.

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Edge Penetration Effects in the Low-Loss Electron Image in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103097 ◽

1988 ◽

Vol 46 ◽

pp. 202-203

Author(s):

Oliver C. Wells

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Beam Energy ◽

Secondary Electron ◽

Sharp Edge ◽

Beam Diameter ◽

Low Loss ◽

Additional Information ◽

Electron Image ◽

Scanning Electron

The low-loss electron (LLE) image in the scanning electron microscope (SEM) is useful for the study of uncoated photoresist and some other poorly conducting specimens because it is less sensitive to specimen charging than is the secondary electron (SE) image. A second advantage can arise from a significant reduction in the width of the “penetration fringe” close to a sharp edge. Although both of these problems can also be solved by operating with a beam energy of about 1 keV, the LLE image has the advantage that it permits the use of a higher beam energy and therefore (for a given SEM) a smaller beam diameter. It is an additional attraction of the LLE image that it can be obtained simultaneously with the SE image, and this gives additional information in many cases. This paper shows the reduction in penetration effects given by the use of the LLE image.

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Electron beam induced current study of thin silicon layers on insulator substrate

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176228 ◽

1990 ◽

Vol 48 (4) ◽

pp. 618-619

Author(s):

A. Buczkowski ◽

Z. J. Radzimski ◽

J. C. Russ ◽

G. A. Rozgonyi

Keyword(s):

Electron Beam ◽

Energy Loss ◽

Beam Energy ◽

Collection Efficiency ◽

Silicon Layer ◽

Depletion Layer ◽

Incident Electron Energy ◽

Induced Current ◽

Electron Hole ◽

Electron Beam Induced Current

If a thickness of a semiconductor is smaller than the penetration depth of the electron beam, e.g. in silicon on insulator (SOI) structures, only a small portion of incident electrons energy , which is lost in a superficial silicon layer separated by the oxide from the substrate, contributes to the electron beam induced current (EBIC). Because the energy loss distribution of primary beam is not uniform and varies with beam energy, it is not straightforward to predict the optimum conditions for using this technique. Moreover, the energy losses in an ohmic or Schottky contact complicate this prediction. None of the existing theories, which are based on an assumption of a point-like region of electron beam generation, can be used satisfactorily on SOI structures. We have used a Monte Carlo technique which provide a simulation of the electron beam interactions with thin multilayer structures. The EBIC current was calculated using a simple one dimensional geometry, i.e. depletion layer separating electron- hole pairs spreads out to infinity in x- and y-direction. A point-type generation function with location being an actual location of an incident electron energy loss event has been assumed. A collection efficiency of electron-hole pairs was assumed to be 100% for carriers generated within the depletion layer, and inversely proportional to the exponential function of depth with the effective diffusion length as a parameter outside this layer. A series of simulations were performed for various thicknesses of superficial silicon layer. The geometries used for simulations were chosen to match the "real" samples used in the experimental part of this work. The theoretical data presented in Fig. 1 show how significandy the gain decreases with a decrease in superficial layer thickness in comparison with bulk material. Moreover, there is an optimum beam energy at which the gain reaches its maximum value for particular silicon thickness.

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Surface recombination effects on minority carrier diffusion length measurements using electron beam-induced current

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017685x ◽

1990 ◽

Vol 48 (4) ◽

pp. 744-745

Author(s):

D.P. Malta ◽

M.L. Timmons

Keyword(s):

Electron Beam ◽

Beam Energy ◽

Minority Carrier ◽

Diffusion Length ◽

Effective Diffusion ◽

Surface Recombination ◽

Surface Recombination Velocity ◽

Logarithmic Scale ◽

Minority Carrier Diffusion Length ◽

Carrier Diffusion

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

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ELECTRON BEAM ENERGY BRANCHING IN OXYGEN

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19797375 ◽

1979 ◽

Vol 40 (C7) ◽

pp. C7-777-C7-778

Author(s):

G. Fournier ◽

J. Bonnet ◽

J. Bridet ◽

J. Fort ◽

D. Pigache

Keyword(s):

Electron Beam ◽

Beam Energy ◽

Electron Beam Energy

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Design of an X -band electron linear accelerator dedicated to decentralized Mo99/Tc99m supply: From beam energy selection to yield estimation

Physical Review Accelerators and Beams ◽

10.1103/physrevaccelbeams.20.104701 ◽

2017 ◽

Vol 20 (10) ◽

Cited By ~ 4

Author(s):

Jaewoong Jang ◽

Masashi Yamamoto ◽

Mitsuru Uesaka

Keyword(s):

Linear Accelerator ◽

Beam Energy ◽

Yield Estimation ◽

Electron Linear Accelerator ◽

Band Electron ◽

X Band

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EDS Quantification Using Fe L Peaks and Low Beam Energy

Microscopy and Microanalysis ◽

10.1017/s1431927621006140 ◽

2021 ◽

Vol 27 (S1) ◽

pp. 1670-1672

Author(s):

Jens Rafaelsen ◽

Frank Eggert ◽

Masanobu Kawabata

Keyword(s):

Beam Energy

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The Forward-Plane Star in $$^1$$H(d, pp)n Breakup at E$$_{{{\varvec{d}}}}=\mathbf{80}$$ MeV/nucleon

Few-Body Systems ◽

10.1007/s00601-021-01653-w ◽

2021 ◽

Vol 62 (4) ◽

Author(s):

A. Wilczek ◽

A. Szadziński ◽

N. Kalantar-Nayestanaki ◽

St. Kistryn ◽

A. Kozela ◽

...

Keyword(s):

Cross Section ◽

Beam Energy ◽

Detector System ◽

Systematic Analysis ◽

Star Configurations

AbstractAnalysis of the data acquired with the BINA detector system in $$^1$$ 1 H(d, pp)n reaction at the beam energy of 80 MeV/nucleon makes a systematic analysis of the star configurations possible. This paper shows the preliminary cross section of the Forward-Plane Star (FPS) configuration with the neighbouring configurations.

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