Polarizer/analyzer filter for nuclear resonant scattering of synchrotron radiation

Abstract

A silicon (840) channel-cut crystal with a large asymmetry is used to linearly polarize synchrotron radiation generated by an undulator source at the 14.413 keV nuclear resonance of 57Fe. The resulting σ̂-polarized radiation is then scattered from an 57Fe foil placed in a magnetic field that effects σ̂→π̂ polarization conversion within the resonant bandwidth. A second crystal of the same type is placed in a crossed position to suppress the nonresonant radiation while transmitting the π̂-polarized resonant radiation. A polarization suppression factor of 6×10−7 has been obtained. The suppression of the nonresonant radiation allowed monitoring the decay of the nuclear levels after 1 ns of their excitation.

Scientific opportunities in nuclear resonance spectroscopy from source-driven revolution

“…4, which uses nuclear resonant scattering to deliver a μeV bandwidth allows one to investigate low-energy excitations. The concept uses a cross polarizer-analyzer pair to suppress the nonresonant radiation allowing only the 14.4 keV resonant X-rays with few μeV bandwidth delivered to the sample [47,48]. The energy of the resonant X-rays is Doppler shifted over ±10 meV range by a high-speed rotor revolving at about 8,000 rotations per minute.…”

A Different Laboratory Tale: Fifty Years of Mössbauer Spectroscopy

“…59 The primary purpose of the APS, Spring-8, and ESRF was to measure molecular vibrations in biological molecules, including proteins, as well as thermodynamic and elastic properties of materials under extreme pressure and temperature (one megabar and 3000 K). 60 The instigator of Argonne's Mössbauer beam line was Ercan Alp. As a student, Alp had worked with traditional Mössbauer spectroscopy at the Middle East Technical University in Ankara, Turkey, and also had spent time with Erich Gerdau at DESY on an International Atomic Energy Agency scholarship.…”

Cavity with Iron Nuclei Slows Down X Rays

“…First, the x rays are directed into a high purity x-ray polarimeter consisting of a polarizer and analyzer in crossed setting [40][41][42], between which the cavity containing the nuclei is placed. Thus, only those photons arrive at the detector, whose polarization has been rotated by the interaction with the nuclei.…”