X0303 4 2011-02-11 0000005768 AMERICAN SCIENCE & ENGINEERING, INC. ASEI 0001237004 HELMER HAMILTON W AMERICAN SCIENCE AND ENGINEERING, INC. 829 MIDDLESEX TURNPIKE BILLERICA MA 01821 1 0 0 0 Common Stock 2011-02-11 4 M 0 7000 28.50 A 16518 D Common Stock 2011-02-11 4 S 0 7000 90.85 D 9518 D Stock Options (Right to Buy) 28.50 2011-02-11 4 M 0 7000 0 D 2005-09-16 2014-09-16 Common Stock 7000 0 D The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from a low of $90.75 to a high of $91.03 for an average of $90.8453. The reporting person undertakes to provide to American Science and Engineering, Inc., any security holder of American Science and Engineering, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote to this Form 4. On September 16, 2004, the reporting person was granted an option to purchase 7,000 shares of common stock. The option vested on the first anniversary of the Grant Date. M. Colette Cooke, Attorney-in-Fact 2011-02-15