ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Education, Training & Workforce Development
The Education, Training & Workforce Development Division provides communication among the academic, industrial, and governmental communities through the exchange of views and information on matters related to education, training and workforce development in nuclear and radiological science, engineering, and technology. Industry leaders, education and training professionals, and interested students work together through Society-sponsored meetings and publications, to enrich their professional development, to educate the general public, and to advance nuclear and radiological science and engineering.
Meeting Spotlight
2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Jun 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
July 2025
Nuclear Technology
Fusion Science and Technology
Latest News
Smarter waste strategies: Helping deliver on the promise of advanced nuclear
At COP28, held in Dubai in 2023, a clear consensus emerged: Nuclear energy must be a cornerstone of the global clean energy transition. With electricity demand projected to soar as we decarbonize not just power but also industry, transport, and heat, the case for new nuclear is compelling. More than 20 countries committed to tripling global nuclear capacity by 2050. In the United States alone, the Department of Energy forecasts that the country’s current nuclear capacity could more than triple, adding 200 GW of new nuclear to the existing 95 GW by mid-century.
Henry Chiu
Fusion Science and Technology | Volume 34 | Number 3 | November 1998 | Pages 564-567
Plasma Engineering (Poster Session) | doi.org/10.13182/FST98-A11963673
Articles are hosted by Taylor and Francis Online.
The neutral beam systems of DIII-D, a National Fusion Facility at General Atomics, are used both for heating the plasma, and as tools for plasma diagnostics. The spatial distribution (profile) and energy of the beam is used in the absolute calibration of both the Charge Exchange Recombination (CER) and Motional Stark Effect (MSE) diagnostics. The CER diagnostic is used to make spatially and temporally resolved measurements of ion temperature and poloidal and toroidal rotational velocities. These measurements are made by visible spectroscopy of the Doppler shifted He II (468.6 nm), C VI (529.1 nm) and B V(494.5 nm) spectral lines, excited by the charge exchange recombination events between the plasma ions and the beam neutrals. As such, the spatial distribution of the beam is needed for an absolute calibration of the CER diagnostic. The MSE diagnostic measures the internal poloidal field profile in the plasma. MSE measures the polarization angle of the Stark broadned neutral beam Dα emission due to the Vbeam × B motional electric field. Again, the spatial profile of the neutral beam is needed for the absolute calibration of the MSE diagnostic.
In the past, the beam spatial profile used in these calibrations was derived from beam divergence calculations and IR camera observations on the tokamak inboard target tiles. Two experimental methods are now available to better determine the beam profile. In one method, the Doppler shifted Dα light from the energetic neutrals are measured, and the full-width at half-maximum (FWHM) of the beam can be inferred from the measured divergence of the Dα light intensity. The other method for determining the beam profile uses the temperature gradients measured by the thermocouples mounted on the calorimeter. A new iterative fitting routine for the measured thermocouple data has been developed to fit theoretical models on the dispersion of the beam. The results of both methods are compared, and used to provide a new experimental verification of the beam profile.
