Double absorber Mössbauer spectroscopy in 183W

Accurate Mössbauer line-shape measurements including interference inW182,Wagoner1, Mullen2, Schupp3 1993Phys. Rev. CSelf Cite7010View full textAdd to dashboardCite

“…That this asymmetry is due to interference is supported by the fact that even with different drive motors, and frequently reworked reciprocation devices and a variety of electronic data collection devices, no system asymmetry was found. In fact, a variety of 46.5-keV tungsten experiments done over a period of several years [7,10] have consistantly returned the same value for P. When only the symmetric part of the line shape is subtracted from the data, the resulting asymmetric line is as expected and is similar to cases we have shown in earlier papers [11].…”

“…Because of the importance of this measurement to timereversal invariance (TI) experiments [6] and the general lack of experimental confirmation of interference values, we chose to redo this measurement and attempt to reduce the error of P = -0.0077 (10) found in the experiment of Bullard, Mullen, and Schupp.…”

Debye-Waller factors of alkali halides

“…The thickness of the absorber and the SRSA were taken as known values from previous high-precision measurements. 11,12 Additionally, we have shown that, provided the actual absorber thickness and SRSA are constant, the elastic scattering fraction does not change for small inaccuracies in the thickness number of the absorber or the source. That is, using a slightly inaccurate value for one of these parameters will affect the recoilless fraction measured in both the before and after positions, but the elastic scattering fraction will be unaffected.…”

“…We oscillated a resonant absorber, a natural tungsten foil 2 mils thick, between the sample crystal and the detector. A line shape analysis of each Mössbauer spectrum, based on an analytic expansion of the transmission integral, [8][9][10][11][12] determined the recoilless fraction of the photon beam after scattering from the sample. The Mössbauer line shape depends on the thickness of the absorber, the SRSA in the source, the recoilless fraction of the source, the width of the transition, and the number of counts collected.…”

“…7 In addition, it allows us to fit our spectra to the true line shape of the transition, rather than assuming a Lorentzian shape, which leads to errors in the measured elastic scattering fraction in on-and off-resonance measurements and even erroneous Debye temperatures. [8][9][10][11][12][13][14] As a source decays, absorber nuclei build up in the source, and source resonance self-absorption ͑SRSA͒ begins to distort the shape of the observed Mössbauer line. We used sources for only 1 week, during which SRSA is negligible.…”