Sequential Impact Mass Spectrometry: Estimates of Metastable Ion Cross Sections

1971 ◽  
Vol 49 (24) ◽  
pp. 3059-3063 ◽  
Author(s):  
P. A. Redhead
Keyword(s):  
Experimental Data ◽  
Mass Spectrometry ◽  
Cross Sections ◽  
Ion Source ◽  
Metastable States ◽  
Ionization Cross ◽  
Trapped Ion ◽  
Charge Multiplicity ◽  
Ionization Cross Sections ◽  
Impact Mass

A trapped-ion source has been developed in which ions can undergo as many as 12 consecutive collisions with electrons; ions leaking out of the trap are analyzed with a mass spectrometer. When long-lived metastable states of the ions exist, the collision sequence may involve metastable states of the ions, e.g.[Formula: see text]where Xn represents an ion of charge multiplicity n, and Xn* represents a metastable ion. In a previous paper an approximate method was developed to estimate ionization cross sections for the case where the collision sequence involved only the ground states of the ions. The present paper extends this model to the case where metastable states are involved, and permits rough estimates of cross sections for excitation to and from the metastable states. The method is applied to experimental data for argon in the electron energy range of 40 to 100 eV.

K-shell ionization cross sections of K and Lα X-ray production cross sections of I by 10–30 keV electron impact

2012 ◽  
Vol 90 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Y. Wu ◽  
Z. An ◽  
Y.M. Duan ◽  
M.T. Liu ◽  
X.P. Ouyang
Keyword(s):  
Experimental Data ◽  
Electron Impact ◽  
Cross Sections ◽  
Production Cross ◽  
Carbon Substrate ◽  
Ionization Cross ◽  
X Ray ◽  
Pure Carbon ◽  
Ionization Cross Sections ◽  
Shell Ionization

The absolute K-shell ionization cross sections of K and Lα X-ray production cross sections of I by 10–30 keV electron impact have been measured. The target was prepared by evaporating a thin film of compound KI to a thick pure carbon substrate. The effects of multiple scattering of electrons penetrating the target films, electrons reflected from the thick pure carbon substrates and bremsstrahlung photons produced when incident electrons impacted on the targets were corrected by using the Monte Carlo method. For K K-shell and I L-shell X-ray characteristic peaks, the spectra were fitted using the spectrum-fitting program ALLFIT to extract the Kα and Kβ peak counts more accurately for element K, and Lα peak counts for element I. The experimental results were compared with some theoretical results developed recently and available experimental data from the literature. The experimental data for I L-shell X-ray production cross sections by 10–30 keV electron impact are given here for the first time.

scholarly journals Applicability of Vaisburd and Evdokimov Model to Ionic Targets

2012 ◽  
Vol 4 (2) ◽  
pp. 307
Author(s):  
F. Sabrin ◽  
M. A. Uddin ◽  
A. K. F. Haque
Keyword(s):  
Experimental Data ◽  
Electron Impact ◽  
Cross Sections ◽  
Empirical Model ◽  
Impact Ionization ◽  
Computer Code ◽  
Linear Least Squares ◽  
Ionization Cross ◽  
Atoms And Molecules ◽  
Ionization Cross Sections

The Vaisburd and Evdokimov proposed an empirical model to calculate the electron impact single ionization cross-sections of atoms and molecules. The model has been applied to some atoms and molecules. To examine the efficiency of the model, the present work applies the model to calculate cross-sections for  Ne-isonuclear series Ne+, Ne2+, Ne3+, Ne4+, Ne5+, Ne6+, Ne7+, Ne8+, Ne9+ . The separate sets of values of the parameters of the model are determined by comparison with the available experimental data using a non-linear least-squares fitting computer code. Keywords: Electron impact ionization; Empirical model; Ionic targets. © 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v4i2.8704 J. Sci. Res. 4 (2), 307-313 (2012)

Measurements of K-shell ionization cross sections of Fe, Ni, and Zn by 7–29 keV electron impact using the thick-target method

2020 ◽  
Vol 98 (10) ◽  
pp. 970-975
Author(s):  
L.X. Tian ◽  
C.C. Dai ◽  
Y.J. Liu
Keyword(s):  
Experimental Data ◽  
Electron Impact ◽  
Cross Sections ◽  
Thick Target ◽  
Tikhonov Regularization Method ◽  
Ionization Cross ◽  
Bremsstrahlung Photons ◽  
Ill Posed ◽  
Ionization Cross Sections ◽  
Shell Ionization

The measurements of K-shell ionization cross sections for Fe, Ni, and Zn were performed using 7–29 keV electron impact on thick targets. Monte Carlo simulations were employed to correct the effects due to the multiple-scattered electrons and bremsstrahlung photons as well as other secondary particles within the thick targets. The so-called Tikhonov regularization method was adopted to deal with the ill-posed inverse problem involved in the thick-target method. The experimental results were compared with the DWBA and PWBA-C-Ex predictions as well as existing experimental data from the literature. It is observed that our experimental data are in better agreement with the theoretical results based on the DWBA model developed by Bote et al.

Electron Impact Ionization Cross Sections of N2 and O2

1975 ◽  
Vol 53 (11) ◽  
pp. 1044-1046 ◽  
Author(s):  
Suresh Chandra ◽  
Udit Narain
Keyword(s):  
Experimental Data ◽  
Energy Range ◽  
Electron Impact ◽  
Cross Sections ◽  
Impact Ionization ◽  
Electron Impact Ionization ◽  
Ionization Cross ◽  
Ionization Cross Sections ◽  
Good Agreement

The ionization cross sections of N2 and O2 have been calculated in the energy range from threshold to 20 keV using a modified approach. The results are in good agreement with the available experimental data.

SEMIEMPIRICAL FORMULAS FOR CALCULATION OF L SUBSHELL IONIZATION CROSS SECTIONS

1994 ◽  
Vol 04 (04) ◽  
pp. 217-230 ◽  
Author(s):  
I. ORLIĆ ◽  
C.H. SOW ◽  
S.M. TANG
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
High Energy ◽  
Universal Function ◽  
High Energy Region ◽  
Ionization Cross ◽  
Section Data ◽  
Data Points ◽  
Ionization Cross Sections ◽  
Similar Paper

Presented are new parameters for the calculation of L subshell ionization cross sections for proton impact using a semiempirical expression. A similar paper was published by our group in early 1993 but the fitting parameters were obtained by using only 2295 experimental L shell cross section data. Since then a large number of experimental data have become available and therefore a new fitting has been performed employing more than 5000 data points. All available data were fitted separately for L1, L2 and L3 subshells. For targets with low atomic numbers (14≤Z≤42), only coefficients for L tot were obtained. Because of the slight Z dependence of the universal function, data were also devised into five sub-groups according to their atomic numbers and fitted separately within each group for L1, L2 and L3 subshells. To extend the energy range of validity of the new fitting function theoretical values were used in the high energy region where experimental data were lacking. Results are compared with ECPSSR predictions and discussed.

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