Negative-muon capture in ionic compounds and some related elements

Abstract

Relative muon capture probabilities for the individual elements of compounds and relative muonic x-ray intensities have been measured for a series of ionic solids and some related elements. Marked similarities are observed in relative K and L series intensities of a single ionic species. independent of bond partner (eg. Cl in NaCl and CaCI 2 ). However. significant K series differences are observed for an element in an ionic versus a covalent situation (eg. Cl in NaCl and in NaC10 4 ), with the higher K x-rays from the covalently bound element showing relative enhancements of as much as a factor of two over the ion. The measured intensities have been compared to the predictions of a meson cascade code, which allows variation in the nuon initial principal quantum meml;>cr (Nf.J) and the parameter a in the commonly used modificd statistical angular momentwn distribution. P(£) = (29-+ 1) exp (a9,).The fit was quite insensitive to the choice of Nf..l (in the neighborhood Nf..l == 17) but the results could not be well fitted with a single value of a. The atomic capture probabilities predicted by recent calculations do not fit the data noticeably better than the Fermi-Teller "2-Law".

Intensity patterns of pionic X-rays emitted from simple molecules

“…In general, it has been found that the modified statistical distribution gives better agreement with the data than the statistical model, but even the former does not always lead to good agreement [6,11,12]. Condo [233 has observed that the modified statistical distribution with the same value of c~ should not be expected to fit both the relative and absolute X-ray yields, since only one parameter is available to allow for a variety of effects, such as distribution over n, uncertainty on the refilling rate and molecular effects.…”

“…It is usually concluded that the refilling is instantaneous or, at least, rapid in comparison with the cascade time [3,11,12] and that the refilling rate in insulators is not significantly different from the rate in metals. In particular, von Egidy and Povel [3] obtained good agreement with X-ray data for mylar by assuming very fast refilling.…”

Measurement of muonic X-ray intensities and Coulomb capture ratios in chlorides

“…A(Z1, Z2)=Za/Z2 (1) where Z 1 and Z2, in our case, are the atomic numbers of the chlorinated element and chlorine, respec-0340-2193/81/0300/0253/$02.00 [13] et al [14] et al [15] et al [16] et al [17] et al [18] et al [11] or also, calculated in closed form, a weaker dependence [12], the latter being…”

Muon capture on35Cl

“…The dominant uncertainties were the measurement uncertainty in the atomic capture fraction of ±7% (see Ref. [21] for details) and the normalization uncertainty in the muonic x-ray calibration of ±15% (see Ref. [11] for details).…”

“…the fraction of muon stops in NaCl that undergo atomic capture on Cl, was taken from Ref. [21] 1 . The factors C ab and C sv accounted for photon absorption in the target and selfvetoing by the suppressor (C ab varied from 1.02 to 1.03 and C sv varied from 1.06 to 1.16).…”