Projects
1) Laser-Compton Scattering (LCS) X-ray sources. Colliding
high-power laser beams with relativistic electron beams produces
tunable quasi-monochromatic x-ray beams that are exceptionally
advantageous for medical imaging (contrast-to-dose ratio is 2-3
orders of magnitude better than conventional x-ray sources),
non-destructive electron beam diagnostics (the spectral and angular
distribution of x-rays reveals electron beam energy and angular
dispersion), non-proliferation (tuning to K-shell edges of
transuranics), and pharmaceutical crystallography. We are continuing
to pursue more intense, more compact and more portable LCS sources.
2) Accelerator-based Positron Annihilation
Spectroscopy. Positron Annihilation Spectroscopy with positron
sources is an old technique (approximately 40 years) to detect
defects, defect density and defect type in materials. The
fundamental limitation of the application of such techniques to
engineering problems is the penetrability of positrons (10s of
microns). We invented, in 2001, bremsstralung-based pair-production
methods to produce positrons throughout the volume of thick samples
(10s of cm). We are continuing to explore new applications and
better beams for these applications.
3) Non-Proliferation and Homeland Security Applications of Photo-Nuclear Physics. This area is primarily measurements of various bremsstrahlung gammainduced emissions with pulsed electron linacs for the detection of fissile material, hazardous material and explosives. The list of such emissions includes prompt and delayed neutrons, prompt and delayed gammas, and “atomic” processes that include Compton scattering, Pair-production and XRF. This work will continue for some time.
4) Radiobiology and Extremophile research. My end of this is the radiation beam delivery, control and dosimetry. High-intensity electron beams allow exploration of new dose and dose-rate questions in radiobiology and extremophile research that, to date, has been dominated by 60Co source irradiation. We are investigating robust dosimetry and control systems that can be correlated to NIST traceable dosimetry systems and do not degrade over time due to radiation damage.
5) Archaeometry with Photon Activation. This work exploits the idea that bremsstrahlung photons can induce short-lived radioactivity that can, in turn, be used to measure the elemental composition of archaeological specimens. Since this technique is non-destructive, it may prove extremely attractive to a broader “artifact” community, such as museum curators, historians, ancient art, etc.
6) Medical Isotope Production. The idea is similar to that of the achaeometry work (above) in that we use bremsstrahlung photons to produce medically-useful short-lived isotopes for imaging and therapy. Early results are quite promising and we are now building a collaboration between a medical isotope provider (Advanced Medical Isotopes), Portneuf Regional Medical Center, INL and IAC to further this research, produce new isotopes that are available nowhere else, and begin to produce useful quantities of currently-accepted isotopes. We will also pursue collaborations with ISU’s College of Pharmacy, if any faculty in that college are interested.