X0303 4 2011-06-01 0000005768 AMERICAN SCIENCE & ENGINEERING, INC. ASEI 0001089767 GRAY PATRICIA AMERICAN SCIENCE AND ENGINEERING, INC. 829 MIDDLESEX TURNPIKE BILLERICA MA 01821 0 1 0 0 SVP and GC Common Stock 2011-06-01 4 M 0 801 61.40 A 7206 D Common Stock 2011-06-01 4 S 0 801 85.69 D 6405 D Stock Option (Right to Buy) 61.40 2011-06-01 4 M 0 801 0 D 2011-05-06 2019-05-15 Common Stock 801 401 D The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from a low of $85.68 to a high of $85.74 for an average of $85.69. 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 May 15, 2009, the reporting person was granted an option to purchase 1202 shares of common stock. The option vests in 3 equal increment based on AS&E's satisfaction of certain performance criteria. The performance criteria was met for two thirds of the shares, resulting in vesting of the option as to 801 shares. /s/ Colette Cooke, attorney-in-fact 2011-06-02