Dr. Larry Hudson contributes to basic and applied x-ray science and is a leading innovator in designing and building sophisticated x-ray diffraction spectrometers. He has also developed new precise measurement approaches in wavelength-dispersive x-ray spectroscopy and imaging. Other work includes the development of standards for, and applications of, x-ray technology in the areas of industrial radiation processing, medicine, and homeland security.

Dr. Hudson leads a NIST program of x-ray spectroscopy of highly-charged ions. This program is unique in its ability to design, build, and field, for a wide variety of basic and applied applications, curved-crystal x-ray spectrometers that are absolutely calibrated to the units of the SI. Present collaborations include studies at: terawatt pulsed accelerator x-ray sources (PITHON and MBS) for nuclear weapons effects and testing at L-3 Communications Titan PSD (San Leandro, CA); the NIST Electron Beam Ion Trap (EBIT) in collaboration with the University of Melbourne, Australia to systematically test quantum electrodynamics calculations of two-electron atomic systems; imaging and spectroscopy at the Electron Cyclotron Resonance Ion Source at the Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI) in Debrecen, Hungary; and, with the Naval Research Laboratory, diagnostic support for the world's largest lasers, OMEGA at the University of Rochester's Laboratory for Laser Energetics and the National Ignition Facility at Livermore National Laboratory.

For the x-ray astronomy community, Dr. Hudson led the pre- and post-flight calibration exercises for several x-ray astronomy space platforms, including building custom, tunable x-ray sources. In response to the Mammography Quality Assurance Act, a curved-crystal spectrometer was developed for medical diagnostic and therapeutic applications. This device was demonstrated in the clinical setting to calibrate the high-voltage applied to medical x-ray sources to an order of magnitude better than commercially available non-invasive techniques. To address the diagnostic needs in laser-produced plasma research, these medical spectrometers have been re-designed to assess laser performance (plasma temperature and density).

Finally, leadership in NIST Strategic Focus Area of Homeland Security began with design and coordination of experiments for the White House Task Force on Mail Irradiation. Validation of the process for the x-ray decontamination of parcel mail resulted in the protocol that is still being used on all packages destined for government zip codes in Washington DC. Dr. Hudson is currently working on development of the DHS national standards for the technical performance of x-ray and gamma-ray screening systems used in homeland security.