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                                    FORM 8-A

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

               FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                    PURSUANT TO SECTION 12(b) OR (g) OF THE
                        SECURITIES EXCHANGE ACT OF 1934


                            Thermo Optek Corporation
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             (Exact name of registrant as specified in its charter)


               Delaware                               04-3283973
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        (State of incorporation                    (I.R.S. Employer
            or organization)                    Identification Number)      


8E Forge Parkway, Franklin, Massachusetts                02038
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(Address of principal executive offices)               (Zip Code)

        Securities to be registered pursuant to Section 12(b) of the Act:

    Title of each class                        Name of each exchange on which
    to be so registered                        each class is to be registered

Common Stock par value
    $.01 per share                             American Stock Exchange, Inc.


        If this Form relates to the registration of a class of debt securities
and is effective upon filing pursuant to General Instruction A.(c)(1), please
check the following box. / /

        If this Form relates to the registration of a class of debt securities
and is to become effective simultaneously with the effectiveness of a
concurrent registration statement under the Securities Act of 1933 pursuant to
General Instruction A.(c)(2), please check the following box. / /

        Securities to be registered pursuant to Section 12(g) of the Act:


                                      None
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                                (Title of Class)

                                      None
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                                (Title of Class)

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                 INFORMATION REQUIRED IN REGISTRATION STATEMENT

Item 1.          Description of Registrant's Securities to be Registered.

        Information concerning the Common Stock, par value $.01 per share, to
be registered hereunder was included in the Registrant's Registration Statement
on Form S-1 filed with the Commission on April 17, 1996, Registration No.
333-03630, under the caption "Description of Common Stock" and in the
Prospectus included in such Registration Statement and is incorporated herein
by reference.

Item 2.          Exhibits.

        To be filed with the Securities and Exchange Commission:

                 Not applicable.

        To be filed with the American Stock Exchange, Inc.:

                a.      Certificate of Incorporation of the Registrant

                b.      By-Laws of the Registrant

                c.      Specimen Common Stock Certificate
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                                   SIGNATURE

        Pursuant to the requirements of Section 12 of the Securities Exchange
Act of 1934, the registrant has duly caused this registration statement to be
signed on its behalf by the undersigned, thereto duly authorized.

May 22, 1996

                                        THERMO OPTEK CORPORATION


                                                
                                        By: /s/ Jonathan Painter
                                            -----------------------------------
                                            Jonathan Painter
                                            Treasurer