scholarly journals Emittance Measurement for Beamline Extension at the PET Cyclotron

2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Sae-Hoon Park ◽  
Sang-Hoon Lee ◽  
Yu-Seok Kim

Particle-induced X-ray emission is used for determining the elemental composition of materials. This method uses low-energy protons (of several MeV), which can be obtained from high-energy (of tens MeV) accelerators. Instead of manufacturing an accelerator for generating the MeV protons, the use of a PET cyclotron has been suggested for designing the beamline for multipurpose applications, especially for the PIXE experiment, which has a dedicated high-energy (of tens MeV) accelerator. The beam properties of the cyclotron were determined at this experimental facility by using an external beamline before transferring the ion beam to the experimental chamber. We measured the beam profile and calculated the emittance using the pepper-pot method. The beam profile was measured as the beam current using a wire scanner, and the emittance was measured as the beam distribution at the beam dump using a radiochromic film. We analyzed the measurement results and are planning to use the results obtained in the simulations of external beamline and aligned beamline components. We will consider energy degradation after computing the beamline simulation. The experimental study focused on measuring the emittance from the cyclotron, and the results of this study are presented in this paper.


Author(s):  
А.Л. Степанов ◽  
В.В. Воробьев ◽  
В.И. Нуждин ◽  
В.Ф. Валеев ◽  
Ю.Н. Осин

AbstractWe propose a method for the formation of porous germanium ( P -Ge) layers containing silver nanoparticles by means of high-dose implantation of low-energy Ag^+ ions into single-crystalline germanium ( c -Ge). This is demonstrated by implantation of 30-keV Ag^+ ions into a polished c -Ge plate to a dose of 1.5 × 10^17 ion/cm^2 at an ion beam-current density of 5 μA/cm^2. Examination by high-resolution scanning electron microscopy (SEM), atomic-force microscopy (AFM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX) microanalysis, and reflection high-energy electron diffraction (RHEED) showed that the implantation of silver ions into c -Ge surface led to the formation of a P -Ge layer with spongy structure comprising a network of interwoven nanofibers with an average diameter of ∼10–20 nm Ag nanoparticles on the ends of fibers. It is also established that the formation of pores during Ag^+ ion implantation is accompanied by effective sputtering of the Ge surface.



Author(s):  
A.J. Tousimis

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.



1995 ◽  
Vol 13 (2) ◽  
pp. 231-241 ◽  
Author(s):  
J.J. MacFarlane ◽  
P. Wang ◽  
J.E. Bailey ◽  
T.A. Mehlhorn ◽  
R.J. Dukart

Kα satellite spectroscopy can be a valuable technique for diagnosing conditions in high energy density plasmas. Kα emission lines are produced in intense light ion beam plasma interaction experiments as 2p electrons fill partially open Is shells created by the ion beam. In this paper, we present results from collisional-radiative equilibrium (CRE) calculations which show how Kα emission spectroscopy can be used to determine target plasma conditions in intense lithium beam experiments on Particle Beam Fusion Accelerator-II (PBFAII) at Sandia National Laboratories. In these experiments, 8–10 MeV lithium beams with intensities of 1–2 TW/cm2 irradiate planar multilayer targets containing a thin Al tracer. Kα emission spectra are measured using an X-ray crystal spectrometer with a resolution of λ/∆λ = 1200. The spectra are analyzed using a CRE model in which multilevel (NL ∼ 103) statistical equilibrium equations are solved self-consistently with the radiation field and beam properties to determine atomic level populations. Atomic level-dependent fluorescence yields and ion-impact ionization cross sections are used in computing the emission spectra. We present results showing the sensitivity of the Kα emission spectrum to temperature and density of the Al tracer. We also discuss the dependence of measured spectra on the X-ray crystal spectral resolution, and how additional diagnostic information could be obtained using multiple tracers of similar atomic number.



2006 ◽  
Vol 33 (8) ◽  
pp. 2912-2914 ◽  
Author(s):  
Tsang Cheung ◽  
Martin J. Butson ◽  
Peter K. N. Yu
Keyword(s):  


1988 ◽  
Vol 126 ◽  
Author(s):  
John F. Knudsen ◽  
R. C. Bowman ◽  
P. M. Adams ◽  
R. Newman ◽  
J. P. Hurrell ◽  
...  

ABSTRACTEpitaxial regrowth of deposited amorphous silicon has been previously described utilizing ion implantation amorphization, ion mixing and thermal anneal. This paper evaluates the effects of these process steps on crystalline quality utilizing Rutherford Backscattering (RBS), x-ray diffraction rocking curves and Raman scattering.In situ (during implantation) regrowth results in defective crystallinity. In contrast, when there is no in situ regrowth, the post anneal crystallinity is equivalent by RBS and x-ray evaluation to virgin single crystal wafers. In situ regrowth is most pronounced during the high beam current ion mixing type implants which produce wafer temperatures of about 250°C. The final crystalline quality which results from different sequences of amorphization and ion mixing implants, is strongly dependent upon the amount of in situ regrowth which has occurred. The greater the in situ regrowth the poorer the final crystalline quality.



MRS Bulletin ◽  
1987 ◽  
Vol 12 (6) ◽  
pp. 30-34 ◽  
Author(s):  
H-J. Gossmann ◽  
L.C. Feldman

AbstractThis article discusses uses of high energy ion beam scattering for materials analysis, including channeling, particle induced x-ray emission (PIXE), and nuclear reaction analysis (NRA). These additional capabilities used in conjunction with RBS equipment provide capabilities for crystalline defect studies and light element detection.



2008 ◽  
Vol 16 (2) ◽  
pp. 6-9
Author(s):  
David O’Hara ◽  
Greg Brown ◽  
Eric Lochner

Although considerable advances have been made in Energy Dispersive Detectors for microanalysis, low energy analysis under 1000eV is still relatively poor due to detector response and inefficient production of low energy x-rays. X-ray optics fabrication methods by O’Hara and measurements by McCarthy et. al. indicated that it should be possible to fabricate x-ray optics that could be used to significantly increase the low energy x-ray flux seen by an EDS detector without increasing the beam current. Such an optic would be useful to increase low energy counts without moving the detector closer, which would simply increase the high energy counts and dead time.



1993 ◽  
Vol 316 ◽  
Author(s):  
Yunosuke Makita ◽  
Tsutomu Iida ◽  
Shinji Kimura ◽  
Stefan Winter ◽  
Akimasa Yamada ◽  
...  

ABSTRACTRecently, we introduced various acceptor impurities into MBE-grown ultra-pure GaAs by conventional high-energy ion implantation and found many novel shallow emissions associated with acceptor-acceptor pairs. Most of these emissions were easily quenched by extremely small amount of residual donor atoms which were unintentionally introduced during doping processes. For the interpretation of impurity effects, the usage of mass-separated atom as dopant source was strongly suggested. Along this consideration, we developed combined ion beam and molecular beam epitaxy (CIBMBE) technology, in which damage-free doping with high mass purity (M/ΔM=100) is expected to be possible. We here present the results of low-energy (100 eV) carbon ion doping using CIBMBE method. Samples were prepared asa function of growth temperature (Tg=400-700°C) and ion beam current. Net hole concentration, |NA-ND| as high as ~1×1020 cm-3 was obtained in as-grown samples. In 2K photoluminescence spectra, emissions due to acceptor-acceptor pairs exhibit specific energy shift with growing |NA-ND|. Results indicate that carbon doping can be made efficiently even at Tg as low as 500°C without any post heat treatment. These results also tell that by CIBMBE method no serious radiation damages are produced and the undesired impurity contamination can be considerably suppressed.



1986 ◽  
Vol 74 ◽  
Author(s):  
B. X. Liu ◽  
L. J. Huang ◽  
C. H. Shang

AbstractMultilayered Ni-Mo films were irradiated by 200keV Xe ions at room temperature to various doses. The beam current density was confined to be less than lμA/cm2 to avoid overheating. The experimental evidences from X-ray diffraction, electrical resistivity, as well 4 as Rutherford Backscattering, indicate that a dose of 7 × 1014/cm2 was the critical one for uniform mixing of the layers and amorphous phase formation in Ni65 Mo35 films. Under this critical dose, various dendritic patterns were formed as revealed by bright field transmission electron microscopy. The microscopic mechanisms of the ion induced dendritic growth are attributed to the cluster formation and the aggregation of the formed clusters.



1993 ◽  
Vol 03 (03) ◽  
pp. 187-214 ◽  
Author(s):  
J.S.C. McKEE

Studies of particle induced X-ray emission (PIXE) have been widespread and detailed in recent years and despite the fact that most data obtained are from low energy 1–3 MeV experiments, the value of higher energy proton work with its emphasis on K X-ray emission has become more marked as time has progressed. The purpose of this review paper is to outline the history of analysis using high energy protons and to compare and contrast the results obtained with those from lower energy analysis using more firmly established analytical techniques. The work described will concentrate exclusively on proton induced processes and will attempt to outline the rationale for selecting an energy, greater than 20 and up to 70 MeV protons for initiating particles. The relative ease and accuracy of the measurements obtained will be addressed. Clearly such X-ray studies should be seen as complementing low energy work in many instances rather than competing directly with them. However, it will be demonstrated that above a Z value of approximately 20, K X-ray analysis using high energy protons is the only way to go in this type of analysis.



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