2008 DPP Meeting
Construction of a New Beamline at the SUNY Geneseo Pelletron Accelerator for Calibrating a Thomson Parabola
Steven Hupcher, Megan Crossman, Charles Freeman; SUNY Geneseo
Christian Stoeckl; Laboratory for Laser Energetics
A newly constructed Thomson Parabola will be used to study the energy spectra of protons and other ions at the Multiterawatt (MTW) laser facility at LLE produced from the illumination of a planar target with an ultra-intense laser light (>1019 W/cm2). Charged particles ejected in the forward direction will be spatially separated and recorded on image plates in the parabola. Beams of protons and alpha particles from the tandem pelletron at SUNY Geneseo were used to establish an energy-to-position calibration for the Thomson Parabola, as well as to calibrate the response of the imaging plates to various particle fluxes. A new beamline with a general-purpose scattering chamber was constructed at the SUNY Geneseo 1.7 MV pelletron accelerator laboratory. The beamline is equipped with a general-purpose 28 inch scattering chamber which includes a target manipulator system, faraday cup, and a mounting for a surface barrier detector.
*Funded in part by a grant from the DOE through the Lab for Laser Energetics
High-Speed RaPToRS
Robert Henchen, Benjamin Esham, William Becker, Edward Pogozelski, Stephen Padalino; SUNY Geneseo
Thomas Sangster, Vladimir Glebov; Laboratory for Laser Energetics
The High-Speed Rapid Pneumatic Transport of Radioactive Samples (HS-RaPToRS) system, designed to quickly and safely move radioactive materials, was assembled and tested at the Mercury facility of the Naval Research Laboratory (NRL) in Washington D.C. A sample, which is placed inside a four-inch-diameter carrier, is activated before being transported through a PVC tube via airflow. The carrier travels from the reaction chamber to the end station where it pneumatically brakes prior to the gate. A magnetic latch releases the gate when the carrier arrives and comes to rest. The airflow, optical carrier-monitoring devices, and end gate are controlled manually or automatically with LabView software. The installation and testing of the RaPToRS system at NRL was successfully completed with transport times of less than 3 seconds. The speed of the carrier averaged 16 m/s. Prospective facilities for similar systems include the Laboratory for Laser Energetics and the National Ignition Facility.
*Funded in part by a grant from the DOE through the Lab for Laser Energetics
Investigating the Relative Biological Effectiveness of a Hydrogen Plasma Bema on Breast Cancer Cells
Kelly Donovan, Susan Thomas, Kate Huggler, Robert O'Donnell, Stephen Padalino; SUNY Geneseo
Proton therapy has become an accepted form of radiation therapy for tumors in the head, brain, neck, lung and prostate. Compared to other forms of radiation, protons can be applied to a more localized area. Due to the unique energy deposition of the proton beam which produces a flattened Bragg peak in the energy spectrum, it is possible to avoid damaging healthy tissue around the tumor. Past studies have consistently shown survival curves for healthy tissue which indicate effective doses in the range of 2-20 Gy. This study utilized a NEC 5SDH Tandem Pelletron Accelerator in the investigation of the irradiation effects on breast cancer cells. A 3 MeV proton beam passed through a 25 micron thick Kapton window which allowed the cells to remain in atmosphere while being irradiated. Proton energy loss and beam straggling through Kapton and air were determined theoretically using TRIM and confirmed by calibration experiments. A shutter system placed between the window and the cell sample was used to control radiation exposure time. A range of radiation exposure times were tested in an attempt to find the optimal dose.
Gamma X: A Full Capture Mode Detector Array for Carbon Activation
Cassarah Brown, Melissa Cummings, Stephen Padalino; SUNY Geneseo
Thomas Sangster, Timothy Duffy, Vladimir Glebov; Laboratory for Laser Energetics
A diagnostic was developed to determine the (?r)2 of a DT reaction via the production of tertiary neutrons. High energy neutrons, in the range of 20 to 32 MeV, were incident upon a carbon disk which became activated via the 12C(n,2n) reaction. The activated carbon was then quickly transported to the counting station where it was placed in a NaI detector system where the C11 decay via positron emission could be detected in the form of back-to-back 511 KeV annihilation gamma rays. The 6 paired detectors in the system were aligned orthogonally on Cartesian axes. In comparison to the previous 2 detector system used at Rochester, the new 6 detector system has improved counting statistics substantially by increasing sample size and collection solid angle. To obtain a better understanding of the effects of non-uniformly activated samples, radioactive copper pellets were distributed within the carbon sample matrix in a variety of volumetric distributions. In doing so the effects of non-isotropic activation on the efficiency of the detector system could be determined.
*Funded in part by a grant from the DOE through the Lab for Laser Energetics
Monte Carlo Modeling of a Carbon-Based ICF Neutron Diagnostic
B.E. Cochran, S.H. Fay, C.M. Kuhn, E.E. Smith, S.L. Stephenson; Gettysburg College
T.C. Sangster, V. Glebov; Laboratory for Laser Energetics
S.J. Padalino; SUNY Geneseo
A carbon diagnostic system is being developed and tested at OMEGA to determine the tertiary neutron yield during an inertial confinement fusion (ICF) implosion. Past computational work has exclusively used MCNPX (Monte-Carlo N-Particle Extended), despite its inability to formally model the true time-dependent radioactive decay of 11C. Tools have been developed to efficiently extrapolate information from Ptrac files in MCNPX. In addition, modeling the system with Geant4 (Geometry and Tracking) as a supplement to the results obtained with MCNPX is in progress. Results will be presented.
*Funded in part by a grant from the DOE through the Lab for Laser Energetics