HNU developed the SEFA-P, a portable X-ray technology, to selectively determine metals concentrations in soils and other media at hazardous waste sites or industrial locations. Three excitation sources are offered with the SEFA-P X-ray fluorescence (XRF) Analyzer: Iron-55, Cadmium-109, and Americium-241.
The SEFA-P in its most basic form consists of the following components: one main cabinet that encloses the sample chamber; the excitation sources; a liquid nitrogen-cooled Si(Li) detector; a preamplifier; spectrometer electronics; an MCA; and a battery charger. The internal battery can power the MCA for 8 hours. The MCA has an RS232 interface that allows the SEFA-P to be externally controlled through a PC or laptop computer. The SEFA-P weighs approximately 50 pounds.
The SEFA-P can be calibrated empirically or using the Compton ratio. Quantitive results for samples are displayed on the PC screen in units of parts per million. The SEFA-P only analyzes soil samples in the intrusive mode; soil samples are placed in sample cups prior to analysis. After calibrating the unit, analyzing quality control samples, and preparing samples, it is possible to analyze 30 to 50 samples in an 8- to 10-hour day.
The SEFA-P is sold with a general license, so the operator does not have to be specifically licensed in each state in which it is used. As of 1995, the SEFA-P retailed for approximately $45,000 depending on the options included. This price includes one in-house operational training course.
The SEFA-P can detect elements from aluminum through uranium in soil or other media, such as those elements at mining and smelting sites, drum recycling facilities, or plating facilities. The instrument can provide real-time, on-site analytical results during field screening and remedial operations. XRF analysis is faster and more cost-effective compared to conventional laboratory analysis.
The SEFA-P has been used at a number of Superfund sites across the country. A SITE demonstration of the SEFA-P was conducted in February 1995. The instrument was used to identify and quantify concentrations of metals in soils. A preliminary evaluation of the results yielded field-based method detection limits, accuracy, and precision data from the analysis of standard reference materials and performance evaluation samples. Comparability of the XRF results to an EPA-approved reference laboratory method was also assessed. An SW-846 method for XRF analysis of soils is scheduled to be published in 1997. A comprehensive evaluation of all results will be presented in a technical report from EPA in 1997.
Source Excited Fluorescence Analyzer-Portable (SEFA-P) XRF Analyzer
EPA PROJECT MANAGER:
Stephen Billets
U.S. EPA
National Exposure Research Laboratory
Characterization Research Division
P.O. Box 93478
Las Vegas, NV 89193-3478
702-798-2232
Fax: 702-798-2261
TECHNOLOGY DEVELOPER CONTACT:
Jack Driscoll
HNU Systems, Inc.
160 Charlemont Street
Newton, MA 02161-9987
800-724-6690
617-964-6690
Fax: 617-558-0056