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                                                             Exhibit 10(c)(xi)


                              EMPLOYMENT AGREEMENT

AS&E(R)

This Agreement is made as of 23 July, 2001 by and between American Science &
Engineering, Inc. (the "Company"), a Massachusetts corporation having its
principal place of business in Billerica, Massachusetts, and Reed O. Clark
(the "Executive").

The Company desires to retain the services of the Executive, and the
Executive is willing to render such services, in accordance with the terms
hereinafter set forth.

Accordingly, the Company and the Executive agree as follows:

1.  The Company agrees to employ the Executive as, and the Executive agrees
to perform the duties of Vice President, International Sales of the Company.

2.  (a)  The Executive's weekly salary shall be $3,846.15 ("Base Salary")
payable not less frequently than on a monthly basis in accordance with
standard company policy for executives. The Executive shall also be eligible
for an annual bonus in an amount of up to fifty (50%) percent of Base Salary
(annualized) based on Executive's performance, as determined by the Company's
CEO, of specific goals to be determined by the CEO. Executive shall also be
granted options to purchase up to 50,000 shares of the company's common stock
subject to the terms and conditions of AS&E's 1997 Non-Qualified Stock Option
Plan, upon approval of the grant by the Board of Directors. The price of the
options will be at the market close price on the American Stock Exchange of
the Executive's first day of employment. The vesting will occur in equal
increments on each of the first three anniversaries of Executive's first day
of employment.

    (b)  The Company will include the Executive in all life insurance,
disability insurance, medical and all other benefit plans maintained by the
Company for the benefit of its Executives.

3.  (a)  The Company shall pay to the Executive the "Severance Payment" in
the event that the Executive is terminated by the Company within sixty (60)
days prior to or twelve (12) months after the occurrence of a "Change of
Control," as defined below. The Severance Payment shall be made at the time
of such termination.

    (b)  The "Severance Payment" shall be a one-time payment equal to the
higher of: (i) the Executive's base salary for one year at the annual rate in
effect one month prior to the occurrence of the Change of Control, or (ii)
the Executive's base salary for one year at the annual rate in effect at the
time of such termination. The Severance Payment shall also include the
continuation of all benefits received by the Executive prior to termination
for a period equal to the lesser of one year or the start of new employment
by the Executive in which he receives substantially similar benefits.


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    (c)  A "Change of Control" shall be deemed to have occurred if:

         (i)  any person (as defined in Section 13(d) or 14 (d)(2) of the
    Securities Exchange Act of 1934) shall have become the beneficial owner of
    50 percent or more of the combined voting power of the Company's voting
    securities;

         (ii)  the Continuing Directors shall have ceased for any reason to
    constitute a majority of the Board of Directors of the Company. For this
    purpose, a "Continuing Director" shall include members of the Board of
    Directors of the Company as of the date of this Agreement and any person
    nominated for election to the Board of Directors of the Company by a vote
    of the majority of the then Continuing Directors;

         (iii) the stockholders approve the complete liquidation or
    dissolution of the Company, or

         (iv) the stockholders approve by the requisite vote any of the
    following transactions:

              (a) a merger or consolidation of the Company (except for a
         merger in respect of which no vote of the stockholders of the Company
         is required);

              (b) a sale, lease, exchange, mortgage, pledge, transfer or
         other disposition (in one transaction or a series of transactions),
         whether as part of a dissolution or otherwise, of assets of the
         Company or of any direct or indirect majority-owned subsidiary or the
         Company (other than to any direct or indirect wholly-owned subsidiary
         or to the Company) having an aggregate market value equal to 50% or
         more of either the aggregate market value of all of the assets of the
         Company determined on a consolidated basis or the aggregate market
         value of all the outstanding stock of the Company immediately prior
         to the transaction; or

              (c) a tender or exchange offer for 50% or more of the
         outstanding voting stock of the Company.

4.  (a)  If the Executive is terminated for any reason other than (i) "Cause"
(as defined below); or (ii) pursuant to a Change of Control as defined in
Paragraph 3 (such reasons other than (i) or (ii) are hereinafter referred to
as "Termination for Convenience") the Executive shall receive an amount equal
to the greater of the amount that would be due under the Company's
then-current severance policy, if any, or six months of his then-current Base
Salary, payable, at the Company's option, on the last date of his employment
or in weekly installments. In case of Termination for Convenience, the
Executive shall be entitled to a continuation of all benefits being received
by him at the time of termination for the lesser of six (6) months from the
date of termination, or until the date in which the Executive begins new
employment in which he receives substantially similar benefits. If the
Executive is Terminated for Convenience within twelve (12) months after a
change in the Company's President/CEO, the Executive shall be entitled to
receive the Severance Payment described in Paragraph 2(b) in place of the
benefits described in this Paragraph 3.

    (b)  For the purposes of this Agreement, "Cause" shall mean: (i) the
determination by the President of the Company that the Executive has failed
to perform his duties in the course of his employment under this Agreement
consistent with those of a Vice President, International Sales, or has failed
to follow the reasonable instructions of, or


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to meet the goals set by, the President of the Company; or (ii) the final
conviction of the Executive for, or his plea of nolo contendere to, a felony
or any other crime that involves fraud, dishonesty or moral turpitude.

5.  The Company may not assign all or any part of its obligations under this
Agreement, except to a successor as provided for in this paragraph. The
Company will require any successor (whether direct or indirect, by purchase,
merger, consolidation or otherwise) to all or substantially all of the
business or assets of the Company expressly to assume and agree to perform
this Agreement to the same extent that the Company would be required to
perform it if no succession had taken place. As used in this Agreement,
unless the context requires otherwise, the "Company" shall mean the Company
as defined above or any successor to its business or assets as aforesaid
which assumes and agrees to perform this Agreement, by operation of law, or
otherwise. This Agreement shall inure to the benefit of and be enforceable by
and binding upon (i) any such successor and (ii) the Executive's personal or
legal representatives, executors, administrators and designated beneficiaries.

6.  This Agreement contains the entire agreement between the parties with
respect to the subject matter hereof and supersedes all prior oral and
written agreements, understandings and commitments between the parties
relating to this Agreement. Notwithstanding the foregoing, the Executive
shall at all times remain subject to all policies and procedures of the
Company that relate to employees of the Company, except to the extent that
this Agreement contains terms or provisions that are contrary to or provides
greater benefits than such policies and procedures, in which case this
Agreement shall control. No amendment to this Agreement shall be made except
by a written instrument signed by both parties.

7.  The Executive shall be entitled to reimbursement or payment of reasonable
moving expenses for Executive's household possessions from Beirut, Lebanon to
the Boston, Massachusetts area, up to a maximum of $50,000. Company shall
also pay to Executive or reimburse reasonable temporary lodging expenses for
Executive and dependants for a period of three (3) months. Expense and
authorization shall be coordinated by the Vice President of Human Resources.
If Executive voluntarily terminates his employment with Company within one
(1) year after date of employment, the Executive shall reimburse to Company
any relocation expenses paid or reimbursed by Company.

8.  The Executive agrees that, during the term of employment by the Company
and during an additional period of (1) year which shall commence at the date
of termination of Executive's employment, he will not:

    (a)  directly or indirectly work for, consult with, be affiliated with
or otherwise provide services for any competitor of the Company, including
without limitation any entity that designs, manufactures or sells x-ray
inspection equipment;

    (b)  Hire, solicit, or attempt to induce any employee of the Company to
leave its employ and to work directly or indirectly for or with Executive or
any employer or contractor of Executive, or


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AS&E(R)


    (c)  Directly or indirectly, individually or for or with any other party,
provide any type of service(s) to any person or entity which was, during the
last 12 months of Executive's employment, a customer or account of the
Company, as would permit, enable or assist such customer in receiving or
providing, for itself or others, products or services like or similar to
those products or services which had been provided to such customer by the
Company during the 12 month period preceding the termination of his
employment.

9.  If any agreement or covenant made by the Executive herein shall, to any
extent, be determined by any court having jurisdiction as being too broad
in area, time, or both, or otherwise to any extent held invalid, then the
part or parts which are determined to be invalid or unenforceable shall
be severed and the remaining parts of this Agreement shall continue in full
force and effect.

10. Executive acknowledges that a breach or threatened breach of any
commitment made by Executive in this Agreement could cause irreparable injury
to the Company; that damages would not adequately compensate the Company for
such breach or threatened breach and that such damages would be difficult to
determine. Therefore, Executive agrees that the Company shall be entitled to
such equitable and injunctive relief as may be available to restrain or
prevent a breach or contemplated breach of any of the obligations of the
Executive in this Agreement. The Company shall have this right in addition to
damages and any other remedy available at law or in equity.

11. The Appendix A AS&E Proprietary Information Procedure is attached hereto
and incorporated into this Agreement.

12. This Agreement shall be construed and enforced under and be governed in
all respects by the law of the Commonwealth of Massachusetts, without regard
to the conflict of law principles thereof.

13. This Agreement supersedes all prior agreements.

IN WITNESS WHEREOF, the Company has caused this instrument to be executed on
its behalf by a duly authorized officer and the Executive has executed this
instrument, all as of the date set forth above.

                                 AMERICAN SCIENCE & ENGINEERING, INC.

                                 By: /s/ Ralph S. Sheridan
                                    ------------------------------------
                                    Ralph S. Sheridan, CEO and President

                                     /s/ Reed O. Clark
                                    ------------------------------------
                                    Reed O. Clark