U.S. Department of Defense Adds Radioactive Threat Detection to Seven MobileSearch X-ray Inspection Systems Recently Ordered from AS&E.

Business Editors/High-Tech Writers

BILLERICA, Mass.--(BUSINESS WIRE)--May 20, 2003

U.S. DoD to Combat Nuclear Devices, Dirty Bombs at Military Bases

American Science and Engineering, Inc. (AMEX:ASE) announced today an order for $350,000 from the U.S. Department of Defense (DoD) to add Radioactive Threat Detection (RTD) to the seven MobileSearch(TM) X-ray inspection systems ordered at the end of April. This order for RTD technology was placed under the blanket purchase agreement awarded to American Science and Engineering (AS&E(R)) in May 2002. The DoD plans to deploy the seven RTD-enhanced systems for military base and force protection.

"With this additional order for RTD technology, the U.S. Government is addressing the risk of a terrorist attack that employs radioactive materials," said Ralph Sheridan, CEO and President. "Using three different technologies - Z(R) Backscatter imaging, transmission X-ray, and RTD technology - AS&E developed a comprehensive tool for the detection of radiological threats while simultaneously producing X-ray images. RTD is highly sensitive to both gamma rays and neutrons - typically associated with dirty bomb materials (such as Cesium 137) or fissile material such as weapon grade plutonium. Transmission X-ray inspection, simultaneously with radiation detection, reveals the presence of lead shielding which may be used to foil radiation sensors. At the same time, Z(R) Backscatter imaging highlights explosives that could propel radioactive isotopes into the atmosphere. The combination of these three technologies provides a high level of protection against the conveyance of a Weapon of Mass Destruction."

Radioactive Threat Detection is particularly important in light of the potential terrorist threat of explosives packaged with radioactive material that scatters upon deployment, commonly referred to as "dirty bombs." Dirty bombs could have serious health and economic implications on the population of a targeted area.

MobileSearch X-ray inspection systems provide DoD officials with a highly effective means for detecting weapons, plastic explosives, illegal drugs and other organic and inorganic contraband - and now, radioactive threats. AS&E currently has 12 MobileSearch systems that will be equipped with RTD technology for both defense and port security applications. The RTD option can be built into new systems, or retrofitted into existing cargo systems.

About AS&E(R)

AS&E develops and manufactures sophisticated X-ray inspection products for critical detection and security applications. These systems are solving an expanding range of inspection problems including detecting car and truck bombs, combating weapons smuggling, and imaging cargo to expose trade fraud and illegal immigration. AS&E's patented Z(R) Backscatter technology detects plastic explosives, illegal drugs, and other contraband, even when artfully concealed in complex backgrounds by terrorists and smugglers. AS&E's Shaped Energy(TM) X-ray inspection systems combine material discrimination features of Z(R) Backscatter imaging with the penetration capability of high-energy X-rays for dense cargoes. AS&E's High Energy Systems Division manufactures linear accelerators for a variety of applications including medical, scientific, security, electron beam curing and non-destructive testing. For more information on AS&E products and technologies, please visit AS&E's web site at http://www.as-e.com.

Safe Harbor Statement

The foregoing press release contains statements concerning AS&E's financial performance, markets and business operations that may be considered ``forward-looking'' under applicable securities laws. AS&E wishes to caution readers of this press release that actual results might differ materially from those projected in any forward-looking statements. There is no guarantee that the Company will receive additional orders under the blanket purchase agreement or, that the order described above will not be canceled. Additional factors which might cause actual results to differ materially from those projected in the forward-looking statements contained herein include the following: significant reductions or delays in procurements of the Company's systems by the United States and other governments; disruption in the supply of any sole-source component incorporated into the AS&E's products; litigation seeking to restrict the use of intellectual property used by the Company; potential product liability claims against the Company; global political trends and events which affect public perception of the threat presented by drugs, explosives and other contraband; global economic developments and the ability of governments and private organizations to fund purchases of the Company's products to address such threats; and the potential insufficiency of Company resources, including human resources, capital, plant and equipment and management systems, to accommodate any future growth. These and certain other factors which might cause actual results to differ materially from those projected are more fully set forth under the caption ``Forward-Looking Information and Factors Affecting Future Performance'' in the Company's Annual Report on Form 10-K for fiscal year ending March 31, 2002.