Subcategory: Physics (not Nanoscience)
Room: Exhibit Hall A
Giraude I. Griffin - Texas Southern University
Co-Author(s): Justice E. Stewart, Department of Physics, Texas Southern University, Houston, TX 77004; Dale C. Kelly, Department of Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180; Mark C. Harvey, Department of Physics, Texas Southern University, Houston, TX 77004; Steve A. Coleman, Radiological Control Division, Brookhaven National Laboratory, Upton, NY 11973
The National Synchrotron Light Source-II (NSLS-II) at the Brookhaven National Laboratory produces synchrotron radiation of ultra-high brightness for high spatial and energy resolution x-ray diffraction experiments. Extensive calculations of the scatter dose rate have been carried out with the FLUKA Monte Carlo simulation package for beamlines at NSLS-II to ensure safe work conditions on the experimental floor. The two major types of radiation studied at NSLS-II consist of synchrotron radiation (SR) and gas bremsstrahlung (GB). X-ray diffraction experiments are carried out with SR, while GB radiation inside the storage ring is a residual property of beam gas interactions. The purpose of this study was to measure the scatter radiation produced inside of the first optical enclosure (FOE) of the 6-BM beamline near the viewports of the double crystal monochromator (DCM). The DCM viewports in 6-BM were monitored and observed to yield the largest scatter dose rates within the FOE. A strong correlation was evident between the scatter dose rate and DCM crystal angle. Measurements of the scatter radiation were performed with the FH 40 G dose rate meter and Canberra InSpectorTM 1000 gamma spectroscopy unit, respectively. Our preliminary results suggest that the gamma dose rate varies inversely with DCM crystal angle from 3.7 mSv/h (~ 24º) to 5.3 mSv/h (~ 5.5º). By contrast, the gamma dose rates were less than about 10 µSv/h for DCM crystal angles greater than approximately 25º due to the construct of the mirror rotational components. In addition, dose rates measured near the lower DCM viewport were more than an order of magnitude smaller than those recorded near the upper DCM viewport. Results calculated with FLUKA will be validated against these measured data in the future.
Funder Acknowledgement(s): NSF-LSAMP
Faculty Advisor: Mark C. Harvey, Ph.D., firstname.lastname@example.org
Role: I conducted the computational Monte Carlo code as well as assist in the setting up of detectors for data acquisition and scatter radiation measurements.