Anomalous fluorescence line intensity in megavoltage bremsstrahlung

作者：Litz M S^*; Merkel G; Pereira N R; Boyer C N; Holland G E; Schumer J W; Seely J F; Hudson L T; Carroll J J

来源：Physics of Plasmas, 2010, 17(4): 043302.

DOI：10.1063/1.3389226

• bremsstrahlung
• fluorescence
• plasma diagnostics
• tungsten

An anomalous ratio between K alpha and K beta fluorescence interpreted with plasma radiation modeling can be a useful diagnostic in laser-produced plasmas. In cold tungsten there exists a similar but as yet undocumented anomaly: for 2 MeV end point bremsstrahlung in the forward direction K beta/K alpha(1)similar or equal to 1, while this ratio is closer to 0.5 for bremsstrahlung in reflection and for an isolated atom. As in the laser-produced plasma, the anomalous ratio reflects a localized source of fluorescence inside the material combined with differential attenuation of the fluorescence photons on their way out. To measure the similar or equal to 60 keV fluorescence lines, a Cauchois transmission crystal spectrograph that works well for laser-produced plasmas must suppress the intense bremsstrahlung that accompanies the fluorescence, by beefing up marginal shielding and avoiding extraneous scatter sources.

• 出版日期2010-4