Deviation from the single-particle model in the angular distribution of thoriumL3x rays in proton-impact ionization

Abstract

Angular distributions of I 3 x-ray transitions, including electric-dipole-forbidden ones, were measured for 1-, 2-, and 3-MeV proton impact on a thorium target, where the excitation and detection systems were cylindrically symmetric. A sophisticated spectrum-analysis technique was applied, where both the ILorentzian broadening of the transitions and the Si(Li) detector response function with various tailing features were taken into account. The anisotropy-parameter ratios are expected to be independent of the ionization process, and to be characteristic of the x-ray transitions in the independent-particle model. The ratios of the anisotropy parameters of the electric-dipole-allowed transitions were in disagreement with this expectation, even when the higher-order multipole contributions were taken into account. These results follow the same trend as earlier angular distribution and angular correlation measurements. Additionally, the electric-dipole-forbidden Lt (L3M2) and Ls (L3M3) transitions had a P4(cos(0)) term, which is not expected within the framework of the single-particle-model predictions.Possible causes for this discrepancy are explored.PACS number(s): 32.30. Rj, 34.50.Fa, 32.80.Hd

Kinematic coefficient ratios, anisotropy parameters, and polarization degrees of L3 X-ray transitions of Bi, Pb, Ta, Lu, and Yb

“…where the superscripts (k = i, j) refer to two different transitions [23]. The %P linear polarization degree can be determined by using…”

“…The expected observed radiation in almost all of these experimental studies [20][21][22][23] has been generally assumed to consist of pure electric dipole (E1) transitions because the accepted very small effect of the magnetic quadrupole mixing higher-order multipole terms (forbidden transitions, such as M1, E2, M2, …) has been overlooked. This approximation is supported by theoretical results [25] obtained using relativistic singleparticle Hartree-Slater wave functions for the X-ray transition matrix element of different multipoles.…”

“…Up to now, many experimental studies related with the angular distribution of the L 3 (J = 3/2) magnetic subshell X-ray transitions using different stimulating sources, such as synchrotron radiation [6][7][8], X-ray tube [9], radioisotope sources [10][11][12][13][14][15][16][17][18], and with charged particles [19][20][21][22][23][24] have been done.…”

Is a sufficient measure of the standard uncertainty in X‐ray spectroscopy?

“…The accuracy of the experimental fundamental parameter data is one of the limitations of the broader application of the fundamental parameter method. One might consider using theoretical model calculations; however, previous studies do not justify the single particle approach based model calculations . For more than a decade, we have created a database for our pure fundamental parameter software for X‐ray fluorescence.…”

Anisotropy ofL-shell X-rays in Au and Hg excited by 59.5 keV photons

“…In recent years, some works were done on this subject, the greater part of them has been extensively investigated both theoretically as well as experimentally by different ions of various energies [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] but little work has been reported on similar studies of vacancy states produced after ionisation by photon [18][19][20][21][22][23]. In this study, 994 M. ERTU~RUL, E. B~i~'KKASAP, A. KU~UKSNDER ETC.…”