Exhibit 8.1

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ROPES & GRAY LLP
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September 22, 2005




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

     Re:  Tax Opinion Regarding Merger of Mt. Hood Corporation with and into
          Helix Technology Corporation and Possible Subsequent Merger of Helix
          Technology Corporation with and into Brooks Automation, Inc.
          --------------------------------------------------------------------

Dear Ladies and Gentlemen:

     We have acted as counsel to Brooks Automation, Inc. ("Brooks") in
connection with the Registration Statement on Form S-4 and Amendment No. 1 to
the Registration Statement on Form S-4 to which this opinion appears as an
exhibit ("Registration Statement"), which includes the Joint Proxy Statement of
Brooks and Helix Technology Corporation ("Helix") and the Prospectus of Brooks
(the "Proxy Statement/Prospectus"). Capitalized terms used but not defined
herein have the meanings ascribed to them in the Agreement and Plan of Merger by
and among Brooks, a Delaware corporation, Mt. Hood Corporation, a Delaware
corporation wholly owned by Brooks ("Sub"), and Helix, a Delaware corporation,
dated as of July 11, 2005 (the "Merger Agreement").

     We have examined the Merger Agreement, which contemplates that Sub will
merge with and into Helix (the "Merger") and which recites that, as part of the
same plan of reorganization, Brooks intends to cause Helix to merge with and
into Brooks (the "Second Merger" and together with the Merger, the "Mergers") as
soon as reasonably practicable after the Merger. We have also examined the Proxy
Statement/Prospectus. We have assumed for purposes of the opinion set forth
below that the Merger will be effected in accordance with the Merger Agreement
(including satisfaction of all covenants and conditions to the obligations of
the parties without amendment or waiver thereof), and as described in the Proxy
Statement/Prospectus. We have also assumed that the Merger, and the Second
Merger if the Second Merger is consummated, will be effected in accordance with
the Delaware General Corporation Law.

     We have also assumed for purposes of the opinion set forth below that the
representation letters, dated as of the date hereof, that Brooks and Helix have
provided to us are true and accurate as of the date hereof and will remain true
and accurate as of the Effective Time and thereafter as relevant. In addition,
we have assumed that if the Second Merger is consummated, the representation
letter provided by Brooks with respect to Brooks and Helix will remain true




Brooks Automation, Inc.               - 2 -                   September 22, 2005



and accurate as of the effective time of the Second Merger and thereafter as
relevant. In addition, we have assumed that all statements in such
representation letters made "to the knowledge" of any person or entity, or
otherwise qualified, are true, correct and complete as if made without such
qualification. Furthermore, we have assumed that, as to all matters in which a
person or entity making a representation has represented that such person or
entity or a related party is not a party to, does not have, or is not aware of,
any plan, intention, understanding or agreement to take an action, there is in
fact no plan, intention, understanding or agreement and such action will not be
taken. We have examined originals, or copies certified or otherwise identified
to our satisfaction, of such records, documents, certificates or other
instruments, and have made such other inquiries, as in our judgment are
necessary or appropriate to enable us to render the opinion set forth below. We
have not, however, undertaken any independent investigation of any factual
matter set forth in any of the foregoing.

     Subject to the foregoing and to the qualifications and limitations set
forth herein, we are of the opinion that for United States federal income tax
purposes, the Merger, or, if the Second Merger is consummated as part of a
single integrated plan with the Merger, the Merger together with the Second
Merger, will be treated as a reorganization within the meaning of Section 368(a)
of the Internal Revenue Code of 1986, as amended (the "Code").

     Our opinion is based on the Code, Treasury Regulations, administrative
interpretations and judicial precedents as of the date hereof, which could
change at any time, possibly with retroactive effect. If there is any subsequent
change in the applicable law or regulations, or if there are subsequently any
new administrative or judicial interpretations of the law or regulations, the
opinion expressed herein may become inapplicable. No ruling has been sought from
the Internal Revenue Service by Brooks, Sub, or Helix as to the federal income
tax consequences of any aspect of the Merger or Second Merger, and neither the
Internal Revenue Service nor any court is bound by our opinion herein. No
opinion is expressed as to any matter not specifically addressed above,
including the tax consequences of the Merger or the Second Merger under any
other federal, state, local, or foreign tax law or the tax consequences of any
other transaction contemplated or entered into by Brooks, Sub, or Helix. We do
not undertake to advise you as to any changes in federal income tax law after
the date hereof that may affect our opinion.

     This opinion is expressed as of the date hereof, and we are under no
obligation to supplement or revise our opinion to reflect any changes (including
changes that have retroactive effect) in applicable law or any information,
document, corporate record, covenant, statement, representation or assumption
stated herein which becomes untrue or incorrect.

     Any inaccuracy in, or breach of, any of the aforementioned factual
statements, representations or assumptions or any change in applicable law after
the date hereof could affect our conclusions.





Brooks Automation, Inc.             - 3 -                     September 22, 2005

     This opinion is solely for your benefit and shall not inure to the benefit
of any other person. It is furnished to you solely for use in connection with
the Mergers and is not to be used, circulated, quoted, or otherwise referred to
for any other purpose without our express written consent. We hereby consent to
the filing with the Securities and Exchange Commission of this opinion as an
exhibit to the Registration Statement and to the use of our name in the sections
of the Proxy Statement/Prospectus entitled "Legal Matters" and "Material U.S.
Federal Income Tax Consequences." In giving this consent, we do not hereby admit
that we are in the category of persons whose consent is required under Section 7
of the Securities Act of 1933, as amended, or the rules and regulations of the
Securities and Exchange Commission thereunder.


                                                Very truly yours,




                                                /s/ Ropes & Gray LLP

                                                Ropes & Gray LLP