Neutron dose rate at the SwissFEL injector test facility: first measurements.

At the Paul Scherrer Institute, the new SwissFEL Free Electron Laser facility is currently in the design phase. It is foreseen to accelerate electrons up to a maximum energy of 7 GeV with a pulsed time structure. An injector test facility is operated at a maximum energy of 300 MeV and serves as the principal test and demonstration plant for the SwissFEL project. Secondary radiation is created in unavoidable interactions of the primary beam with beamline components. The resulting ambient dose-equivalent rate due to neutrons was measured along the beamline with different commercially available survey instruments. The present study compares the readings of these neutron detectors (one of them is specifically designed for measurements in pulsed fields). The experiments were carried out in both, a normal and a diagnostic mode of operation of the injector.

[Spontaneous elimination of helicobacter pylori infection in children]. / Spontanelimination bei Helicobacter-pylori-Infektionen im Kindesalter?

BACKGROUND: With the (13)C-urea-breath test, 6.6 % of 3 372 preschool children of the Leipzig area tested H. pylori positive in 1998. PATIENTS: In 2000, 5.6 % of 3 854 grade-two pupils of the same area tested positive. METHOD: 2 235 children participated in both tests campaigns. Therefore, their H. pylori state could be reinvestigated after two years. RESULTS: 30 of the 104 children, who were tested positive in 1998 were negative in 2000. Using questionnaires completed by the corresponding parents and family physicians, possible reasons of individual elimination were analysed. It was found that 18 of the 25 children received a H. pylori triple therapy. Three children had been tested false-positive in 1998. Four children received antibiotics for other reasons and H. pylori was obviously eradicated too. Only three children were not treated with any antibiotics between 1998 and 2000. For these children, spontaneous elimination is assumed. CONCLUSIONS: Conclusions about spontaneous elimination of H. pylori infections are problematic. Further investigations are needed in consideration of this object.