Induced Radioactivity in Lead Shielding at the National Synchrotron Light Source.

The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory was shut down in September 2014. Lead bricks used as radiological shadow shielding within the accelerator were exposed to stray radiation fields during normal operations. The FLUKA code, a fully integrated Monte Carlo simulation package for the interaction and transport of particles and nuclei in matter, was used to estimate induced radioactivity in this shielding and stainless steel beam pipe from known beam losses.

High-q-resolution neutron scattering technique using triple-axis spectrometers.

A new technique is presented that gives a substantial increase in the wavevector q resolution of triple-axis spectrometers by matching the measurement wavevector q to the reflection taua of a perfect-crystal analyzer. A relative Bragg width of deltaq/Q approximately 10(-4) can be achieved with reasonable collimation settings. This technique is very useful in measuring small structural changes and line broadenings that cannot be accurately measured with conventional set-ups, while keeping all the strengths of a triple-axis spectrometer.