Home » My Experience » Oak Ridge National Laboratory — Experimental Nuclear Physics, RMS and Detector Development

Oak Ridge National Laboratory — Experimental Nuclear Physics, RMS and Detector Development

Holifield Radioactive Ion Beam Facility (HRIBF), X-10 Site
1994 to 2003

I spent nearly a decade at Oak Ridge National Laboratory as part of the small core research group responsible for designing, building, commissioning, and operating the Recoil Mass Spectrometer (RMS) and associated detector systems. These years defined some of the most technically demanding and transformative work of my life.

My role spanned ion optics, high-vacuum systems, charged-particle detectors, beam tuning, real-time data acquisition, and hands-on experimental runs that contributed to new isotope discoveries near the neutron drip line.

This work was performed under the U.S. Department of Energy, Lockheed Martin, UT-Battelle, and the University of Tennessee Knoxville Physics Department.

Core Scientific Contributions

Recoil Mass Spectrometer Development

  • Co-built the RMS, a precision instrument for isolating rare isotopes produced in proton–heavy-metal collisions
  • Designed and tuned ion optics, electromagnetic fields, and slit systems for mass separation
  • Commissioned major RMS subsystems documented in ORNL TM-2000/68 and related NIM publications

Detector Engineering

  • Built and operated double-sided silicon strip arrays, ionization chambers, position-sensitive avalanche counters (PSAC), Ge Clover arrays, and time-of-flight detectors
  • Developed non-destructive beam diagnostics and detector-alignment methodologies
  • Helped design detector configurations later adopted by international facilities including CERN

Isotope Discovery

  • Contributed to experiments leading to the discovery of seven new neutron-rich isotopes
  • Participated in extended experimental campaigns near the nuclear drip line
  • Supported research that expanded the chart of nuclides in collaboration with K. Rogachevsky, C.J. Gross, D. Shapira, and others

Beam Physics and Experimental Runs

  • Coordinated with the tandem accelerator and cyclotron complex for beam delivery
  • Performed real-time field tuning, slit optimization, PID calibration, and detector alignment
  • Conducted overnight and multi-day measurement runs, maintaining system integrity and data quality

Data Acquisition and Software Control

  • Built DAQ processes for real-time capture, filtering, and experimental feedback
  • Integrated hardware outputs into software-based control and analysis pipelines

Collaborators and Institutional Ties

Primary Scientific Colleagues

Inter-Facility Collaboration

Select Publications and References

My contributions revolve around experimental nuclear physics, primarily utilizing the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility. (These represent citations where J. Mas, J. F. Mas, Mas. or Joseph Mas appears.) MY Key areas of research include:

  • Development and Performance of Experimental Equipment: Description and performance evaluation of the Recoil Mass Spectrometer (RMS) and its detector systems at the Holifield Radioactive Ion Beam Facility (HRIBF) Gross et al., 2000.
  • Proton Radioactivity and Exotic Nuclei: J. Mas was involved in the observation and study of proton emission from exotic nuclei:
    • Observation of the exotic nucleus 145 Tm via its direct proton decay, noting its short half-life Batchelder et al., 1998.
    • Identification of a proton-emitting isomer in 151 Lu and determination of its proton energy and half-life, concluding it is a d3/2 proton state Bingham et al., 1999.
    • Studies on proton emission from 150 Lu, remeasuring a previously observed state’s half-life and identifying a new proton-emitting state Ginter et al., 1999.
  • Coulomb Excitation Studies: Research on nuclear structure through Coulomb excitation experiments:

Permanent Archival Sources

Distinctions

  • Full U.S. Department of Energy Scholarship — Science and Engineering Research
  • Certificates of Mastery in Ion Optics and Mass Spectroscopy
  • Contributor to over 30 peer-reviewed papers across PRC, NIM, Phys Lett
  • Work cited globally for detector methodology and isotope discovery
  • Components designed during this period remain in use at multiple labs

Personal Notes From This Era

These were some of the most intense and meaningful years of my life. We worked countless overnight shifts, sleeping on cots in the control room between beam cycles. We spent years preparing, tuning, and validating experimental setups, often chasing a single measurement opportunity that might only exist for milliseconds. –Its about understanding the fundamentals.

What the papers do not show is the mentorship, the camaraderie, the failures, the breakthroughs, the ringing alarms at 3 a.m., the smell of ozone from the beamline, the sound of cryopumps, or the sheer pride of building (or breaking down) something on the atomic scale with our own hands.

The scientists I worked with were, and still are, some of the most brilliant minds in nuclear physics. Those years shaped how I think, how I approach systems, and how I solve problems. They are the foundation beneath everything I do today. –Mentorship passes the torch with greater knowledge and perpetuates continuation of discovery.

My advisor at the lab, Dan Shapira, and close working colleague, Carl Gross, both became American Physical Society Fellows: https://www.ornl.gov/news/four-ornl-researchers-named-american-physical-society-fellows

Back then I wondered how the research would be applied, now, every time I experience a PET or CAT scans (you can hear the cryopumps I mention if you listen next time), I think back to the GE detector work those brilliant minds let me be involved with and how it has evolved all these years later. –Science makes the world a better place.