The Applied Physics Institute in conjunction with Advanced Nuclear Technology, Inc. is developing a on-line cross-belt analyzer for cement. The system will utilize a pulsing d-D neutron source.

The system is a second-generation on-line cement analyzer that represents an advance in this field and addresses the following issues with the current systems:

• Cf-252 based systems cannot operate with accuracy over wide ranges of elemental content in raw materials. They have precision but no accuracy since the sensitivity of the system depends on such external factors as moisture content, neutron absorbing elements, etc.

• Due to the energy of the neutrons emitted from Cf-252, it is impossible to directly measure Na and K. As cement science progresses, we are learning that impurities from these two elements can have long term detrimental effects on concrete.

• The half-life of the Cf-252 source is an issue at cement plants where the analyzer is not used 24 hours/day and 7 days/week. If the analyzer is not used in this manner, the Cf-252 is wasted.

• Measurement using 14 MeV neutrons requires a large amount of shielding (26,000 kg) in order to minimize the radiological exclusion zone created by the highly penetrating 14 MeV neutrons.

• The 14 MeV neutrons from the d-T neutron generator cannot be moderated efficiently.  Thus, for this application, higher neutron fluences are required to overcome this efficiency problem.

The d-D reaction has not been utilized in the past due to its low yield. However, First Point Scientific has developed new neutron tube technology which allows long life (3000 hours) and high yield (108 n/s).

Advance Nuclear Technology, Inc., a Bowling Green, KY-based firm, has obtained an SBIR Phase I Grant (http://www.eng.nsf.gov/sbir/) to commercially develop the device.

• Figure 1. Typical design of a cross-belt analyzer.
  Raw materials are transported by a conveyor belt past a neutron source and a suitable array of detectors.