EXHIBIT 5.01


                                       April 29, 2002



Brooks Automation, Inc.
15 Elizabeth Drive
Chelmsford, MA 01824

         Re: Registration Statement on Form S-3 of Brooks Automation, Inc.


Ladies and Gentlemen:

         We have acted as counsel to Brooks Automation, Inc., a Delaware
corporation (the "Company"), in connection with the preparation and filing
with the Securities and Exchange Commission (the "Commission") of a
Registration Statement on Form S-3 (the "Registration Statement") pursuant
to which the Company is registering under the Securities Act of 1933, as
amended (the "Act"), a total of 153,625 shares of the Company's common
stock, $.01 par value (the "Company Shares"), and 153,625 preferred share
purchase rights (the "Rights"). Pursuant to the Registration Statement and
an Amended and Restated Agreement and Plan of Merger dated December 18,
2001 (the "Merger Agreement") by and among the Company, PRI Automation,
Inc. ("PRI Automation") and Pontiac Acquisition Corp., the Company proposes
to offer to the holders of exchangeable shares of PRI Automation (Canada),
Inc., a controlled subsidiary of PRI Automation, the Company Shares and the
Rights upon the exchange of such exchangeable shares. This opinion is being
rendered in connection with the filing of the Registration Statement.

         For purposes of this opinion, we have assumed, without any
investigation, (i) the legal capacity of each natural person, (ii) the full
power and authority of each entity and person other than the Company to
execute, deliver and perform each document heretofore executed and
delivered or hereafter to be executed and delivered and to do each other
act heretofore done or hereafter to be done by such entity or person, (iii)
the due authorization by each entity or person other than the Company of
each document heretofore executed and delivered or hereafter to be executed
and delivered and to do each other act heretofore done or to be done by
such entity or person, (iv) the due execution and delivery by each entity
or person other than the Company of each document heretofore executed and
delivered or hereafter to be executed and delivered by such entity or
person, (v) the legality, validity, binding effect and enforceability of
each document heretofore executed and delivered or hereafter to be executed
and delivered by each entity or person other than the Company and of each
other act heretofore done or hereafter to be done by such entity or person,
(vi) the genuineness of each signature on, and the completeness of each
document submitted to us as an



Brooks Automation, Inc.
April 29, 2002
Page 2


original, (vii) the conformity to the original of each document submitted to us
as a copy, (viii) the authenticity of the original of each document submitted to
us as a copy, (ix) the completeness, accuracy and proper indexing of all
governmental and judicial records searched and (x) no modification of any
provision of any document, no waiver of any right or remedy and no exercise of
any right or remedy other than in a commercially reasonable and conscionable
manner and in good faith.

         In connection with this opinion, we have examined the following
(collectively, the "Documents"):

         (i)      the Certificate of Incorporation of the Company, as amended;

         (ii)     the Bylaws of the Company;

         (iii)    the Merger Agreement;

         (iv)     the Combination Agreement dated as of November 24, 1998
                  between PRI Automation, Inc., 1325949 Ontario Inc. and Promis
                  Systems Corporation Ltd.;

         (v)      the Voting and Exchange Trust Agreement among PRI Automation,
                  Inc., 1325949 Ontario Inc., Promis Systems Corporation Ltd.
                  and Montreal Trust Company of Canada, as trustee.;

         (vi)     the Exchangeable Share Provisions (as defined in the Voting
                  and Exchange Trust Agreement) in the form in which they will
                  be amended (at the time of the merger under the Merger
                  Agreement);

         (vii)    the Support Agreement among PRI Automation, Inc., 1325949
                  Ontario Inc., and Promis Systems Corporation Ltd.;

         (viii)   the Form of Supplement to Voting and Exchange Trust Agreement
                  among the Registrant, 1325949 Ontario Inc., Brooks-PRI
                  Automation (Canada), Inc. and Montreal Trust Company of
                  Canada, as trustee.;

         (ix)     the Form of Supplement to Support Agreement among the
                  Registrant, 1325949 Ontario Inc., and Brooks-PRI Automation
                  (Canada), Inc.;

         (x)      the Rights Agreement between the Company and Bank Boston,
                  N.A., as Rights Agent dated as of July 23, 1997 (the "Rights
                  Agreement"); and

         (xi)      the Registration Statement.

         The Documents listed in clauses (v)--(ix) above are hereafter referred
to as the Exchangeable Share Documents.

         The opinions expressed herein are based solely upon (i) our review
of the Documents, (ii) discussions with those of our attorneys who have
devoted substantive attention to the matters contained herein, and (iii)
such review of published sources of law as we have deemed necessary.

         We have not, except as specifically noted herein, made any
independent review or investigation of orders, judgments, rules or other
regulations or decrees by which the Company or any of its property may be
bound. Nor have we made any independent investigation as to the existence
of actions, suits, investigations, or proceedings, if any, pending or
threatened against the Company.

         Our opinions contained herein are limited to the laws of The
Commonwealth of Massachusetts, the General Corporation Law of the State of
Delaware, including the statutory provisions, all applicable provisions of the
Delaware Constitution, and reported judicial decisions interpreting these laws,
and the federal law of the United States of America.

         Based upon and subject to the foregoing, we are of the opinion that
upon consummation of the mergers contemplated by the Merger Agreement and
issuance of the Company Shares in accordance with the terms of the Exchangeable
Share Documents: (i) the Company Shares will be duly authorized, validly issued,
fully paid and non-assessable; and (ii) the Rights will be duly authorized,
validly issued, fully paid and non-assessable.

         We understand that this opinion is to be used in connection with
the Registration Statement. We consent to the filing of this opinion as an
exhibit to said Registration Statement and to the


Brooks Automation, Inc.
April 29, 2002
Page 3


reference to our firm wherever it appears in the Registration Statement,
including the prospectus constituting a part thereof and any amendments and
supplements thereto.

                                       Very truly yours,

                                       /s/ BROWN RUDNICK BERLACK ISRAELS LLP


DHM/SPW/CAW