Characterization of the radiation field surrounding the Leksell Gamma Knife® and shielding applications.

The aim of this study is to improve the characterization and modeling of the radiation field surrounding the Leksell Gamma Knife®-Perfexion. The improved characterization of the radiation field enables more accurate shielding calculations to be performed for the areas adjacent to the treatment room. With the aid of a high-purity germanium detector and a satellite dose rate meter, γ-ray spectra and ambient dose equivalent H*(10) data were acquired at various locations in the field of a Leksell Gamma Knife unit in a treatment room at Karolinska University Hospital, Sweden.

Double-pionic fusion of nuclear systems and the "ABC" effect: approaching a puzzle by exclusive and kinematically complete measurements.

The ABC effect-a puzzling low-mass enhancement in the pipi invariant mass spectrum, first observed by Abashian, Booth, and Crowe-is well known from inclusive measurements of two-pion production in nuclear fusion reactions. Here we report on the first exclusive and kinematically complete measurements of the most basic double-pionic fusion reaction pn-->dpi;{0}pi;{0} at beam energies of 1.03 and 1.

A new surface laboratory for measurements of low-level radioactivity.

A laboratory for measuring low-level radioactivity has been built at the AlbaNova University Center in Stockholm. Low-level concrete in combination with a 5 cm iron lining provide an average photon fluency rate from terrestrial sources at least a factor of 40 below that in the common laboratories of the Center. The radon activity inside the laboratory has been measured to (3+/-2) Bq m(-3).