Radiological characterisation of photon radiation from ultra-high-intensity laser-plasma and nuclear interactions

With the increasing number of multi-terawatt (10(12) W) and petawatt (10(15) W) laser interaction facilities being built, the need for a detailed understanding of the potential radiological hazards is required and their impact on personnel is of major concern. Experiments at a number of facilities are being undertaken to achieve this aim. This paper describes the recent work completed on the Vulcan petawatt laser system at the CCLRC Rutherford Appleton Laboratory, where photon doses of up to 43 mSv at 1 m per shot have been measured during commissioning studies. It also overviews the shielding in place on the facility in order to comply with the Ionising Radiation Regulations 1999 (IRR99), maintaining a dose to personnel of less than 1 mSv yr(-1) and as low as reasonably practicable (ALARP)

Radiological characterisation of Petawatt laser interactions

Vulcan is established as a world leading user facility for studies of ultra-high intensity laser interactions with matter. The Petawatt(PW) Upgrade project will deliver an order of magnitude increase in laser power to target, delivering interaction intensities of 10 21 Wcm -2. Before commencing operation to users a commissioning study was carried out. The objectives of this investigation were: To perform radiological surveys of the facility in anticipated target configurations and to install additional shielding for high-Z interactions as required To measure the target irradiance and the X-ray spot size To investigate the effects of electromagnetic noise on the chamber and target area equipment To determine the level of debris produced from the target and to devise a suitable operating scheme to protect chamber optics from damage Installation of an optical probe Contrast measurement of the laser pulses This report will review the experimental and radiological data obtained from the thirteen solid target interaction shots fired during the commissioning run in the newly constructed PW interaction facility 1) where doses of 45 mSv @ 1m were obtained. Commissioning of the PW laser and compressor chain is reported in separate articles, as is the commissioning of the large aperture gratings at high laser fluences 2)

Sexual Dating Aggression Across Grades 8 Through 12: Timing and Predictors of Onset

Investigators have identified a number of factors that increase risk for physical and psychological dating abuse perpetration during adolescence, but as yet little is known about the etiology of sexual dating aggression during this critical developmental period. This is an important gap in the literature given that research suggests that patterns of sexual dating violence that are established during this period may carry over into young adulthood. Using a sample of 459 male adolescents (76% White, 19% Black), the current study used survival analysis to examine the timing and predictors of sexual dating aggression perpetration onset across grades 8 through 12. Risk for sexual dating aggression onset increased across early adolescence, peaked in the 10(th) grade, and desisted thereafter. As predicted based on the Confluence Model of sexual aggression, associations between early physical aggression towards peers and dates and sexual aggression onset were stronger for teens reporting higher levels of rape myth acceptance. Contrary to predictions, inter-parental violence, prior victimization experiences, and parental monitoring knowledge did not predict sexual dating aggression onset. Findings support the notion that risk factors may work synergistically to predict sexual dating aggression and highlight the importance of rape myth acceptance as a construct that should be addressed by violence prevention programs