LOAN AGREEMENT

This Agreement is dated this 3rd day of June, 1997, by and between FLEET
NATIONAL BANK, a national banking association with an office at 777 Main Street
Hartford, Connecticut, 06115 (the "LENDER") and ZYGO CORPORATION, P.O. Box 448,
Middlefield, Connecticut 06445-0448 ("Borrower").

SECTION 1. Definitions. For purposes of this Agreement, the following terms
shall have the meanings specified below:

      a.    "Affiliate" means (i) any person directly or indirectly
            controlling or controlled by or under direct or indirect common
            control with the Borrower or any other obligor of the
            Obligations, as the case may be (including, without limitation,
            any respective director or officer of the Borrower or any other
            obligor of the Obligations, as the case may be), and (ii) any
            corporation or other organization of which the Borrower owns
            more than fifty percent (50%) of the voting securities of such
            entity.

      b.    "Capital Assets" means assets that in accordance with GAAP are
            required or permitted to be depreciated or amortized on the
            Borrower's balance sheet.

      c.    "Capital Leases" means capital leases, conditional sales contracts
            and other title retention agreements relating to the purchase or
            acquisition of Capital Assets.

      d.    "Code" means the Internal Revenue Code of 1986, as amended, or any
            successor federal tax code, and any reference to any provision shall
            be deemed to include a reference to any successor provision or
            provisions.

      e.    "Current Assets" means current assets as determined in accordance
            with GAAP.

      f.    "Current Liabilities" means current liabilities as determined in
            accordance with GAAP.

      g.    "Current Ratio" means Current Assets divided by Current
            Liabilities.

      h.    "Date of Closing" means the date on which this Agreement and the
            Note are executed by Borrower.

      i.    "Debt" means the Total Liabilities of the Borrower.

      j.    "Environmental Laws" means any and all applicable federal, state and
            local environmental, health or safety statutes, laws, regulations,
            rules, ordinances, guidances, policies and rules or common law
            (whether now existing or hereafter


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             enacted or promulgated), of all governmental agencies, bureaus or
             departments which may now or hereafter have jurisdiction over
             Borrower or Borrower's property and all applicable judicial and
             administrative and regulatory decrees, judgments and orders,
             including common law rulings and determinations, relating to injury
             to, or the protection of, real or personal property or human health
             or the environment, including, without limitation, all requirements
             pertaining to reporting, licensing, permitting, investigation,
             remediation and removal of emissions, discharges, releases or
             threatened releases of Hazardous Materials, chemical substances,
             pollutants or contaminants whether solid, liquid or gaseous in
             nature, into the environment or relating to the manufacture,
             processing, distribution, use, treatment, storage, disposal,
             transport or handling of such Hazardous Materials, chemical
             substances, pollutants or contaminants.

      k.    "ERISA" means the Employee Retirement Income Security Act of 1974
            and all rules and regulations promulgated pursuant thereto, as the
            same may from time to time be supplemented or amended.

      l.    "Event of Default" shall have the meaning assigned in Section 6
            hereof.

      m.    "GAAP" means generally accepted accounting principles in the United
            States of America, as from time to time in effect.

      n.    "Hazardous Material" means any substance: (i) the presence of
            which requires or may hereafter require notification,
            investigation, monitoring or remediation under any Environmental
            Law; (ii) which is or becomes defined as a "hazardous waste",
            "hazardous material" or "hazardous substance" or "toxic
            substance" or "pollutant" or "contaminant" under any present or
            future Environmental Law or amendments thereto including,
            without limitation, the Comprehensive Environmental Response,
            Compensation and Liability Act (42 U.S.C. Section 9601 et seq.)
            and any applicable local statutes and the regulations
            promulgated thereunder; (iii) which is toxic, explosive,
            corrosive, reactive, ignitable, infectious, radioactive,
            carcinogenic, mutagenic or otherwise hazardous and is or becomes
            regulated by any governmental authority, agency, department,
            commission, board, agency or instrumentality of any foreign
            country, the United States, any state of the United States, or
            any political subdivision thereof to the extent any of the
            foregoing has or had jurisdiction over Borrower or of Borrower's
            property; or (iv) without limitation, which contains gasoline,
            diesel fuel or other petroleum products, asbestos or
            polychlorinated biphenyls.

      o.    "Indebtedness" of an entity means such entity's (i) obligations
            for borrowed money, (ii) obligations representing the deferred
            purchase price of property other than accounts payable arising in
            the ordinary course of such entity's business on terms customary
            in the trade, (iii) obligations, whether or not assumed, secured
            by a lien on, or payable out of the proceeds or production from,
            property now or hereafter

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<PAGE>



            owned or acquired by such entity, (iv) obligations which are
            evidenced by bonds, debentures, notes, acceptances, or other
            instruments and (v) Capital Lease obligations.

      p.    "IRS" means the United States Internal Revenue Service.

      q.    "Loan" means the Loan evidenced by the Note.

      r.    "Loan Documents" shall have the meaning assigned in Section 3.3
            hereof

      s.    "Net Worth" means Total Assets less Total Liabilities.

      t.    "Note" means promissory note of Borrower dated the same date as
            this Agreement in the original principal amount of $3,000,000.

      u.    "Obligations" means and includes all loans, advances, interest,
            indebtedness, liabilities, obligations, guaranties, covenants and
            duties at any time owing by the Borrower to Lender of every kind and
            description, whether or not evidenced by any note or other
            instrument, whether or not for the payment of money, whether direct
            or indirect, absolute or contingent, due or to become due, now
            existing or hereafter arising, including, but not limited to, the
            Loan and all other indebtedness, liabilities and obligations arising
            under this Agreement and the other Loan Documents and all costs,
            expenses, fees, charges and attorneys', paralegals' and professional
            fees incurred in connection with any of the foregoing, or in any way
            connected with, involving or relating to the preservation,
            enforcement, protection or defense of, or realization under this
            Agreement, the Note, any of the other Loan Documents, any related
            agreement, document or instrument and the rights and remedies
            hereunder or thereunder, and in connection with any "workout" or
            default resolution negotiations involving legal counsel or other
            professionals and any re-negotiation or restructuring of any of the
            Obligations.

      v.    "PBGC" shall have the meaning assigned in Section 5.21a.

      w.    "Plan" means any employee benefit plan or other plan maintained for
            employees of Borrower or any related entity covered by Title I of
            ERISA.

      x.    "Property" shall have the meaning assigned in Section 5.5 hereof.

      y.    "Total Assets" means total assets determined in accordance with
            GAAP.

      z.    "Total Liabilities" means all liabilities determined in accordance
            with GAAP.

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SECTION 2. The Loan Transaction.

2.1.          The Loan. Lender shall lend to the Borrower the sum of
              $3,000,000. The Borrower's obligations to repay the Loan are as
              contained in this Agreement and the Note, a copy of which is
              attached to this Agreement as SCHEDULE 2.1. The Borrower shall
              pay an annual line of credit fee in the amount of $7,500 which
              shall be payable in quarterly installments of $1,875 on the
              first day of January, April, July and October of each year. The
              Loan shall be payable upon DEMAND. There shall be no principal
              amount outstanding on the Loan for a period of 30 consecutive days
              in each fiscal year of Borrower. The Loan shall terminate on
              November 26, 1997.

2.2.          Advances. Lender shall make advances to Borrower under the Loan in
              an aggregate amount not to exceed $3,000,000 provided no defaults
              or Events of Default exist at the time of the advance.

2.3.          Payments on the Loan.

              a.  Regularly Scheduled Payments. Regularly scheduled payments
                  on the Loan shall be made in accordance with the Note.

              b.  Additional Payments. If Lender shall deem applicable to
                  this Agreement, the Loan or the Note (including the
                  borrowed and the unused portion thereof) any requirement
                  of any law of the United States of America, any
                  regulation, order, interpretation, ruling or official
                  directive or guideline (whether or not having the force of
                  law) of the Board of Governors of the Federal Reserve
                  System, the Comptroller of the Currency, the Federal
                  Deposit Insurance Corporation or any other board or
                  governmental or administrative agency of the United States
                  of America which shall impose, increase, modify or make
                  applicable thereto or cause to be included in, any
                  reserve, special deposit, capital adequacy, calculation
                  used in the computation of regulatory capital standards,
                  assessment or other requirement which imposes on Lender or
                  any entity that controls Lender any cost that is
                  attributable to the maintenance thereof, then, and in each
                  such event, Borrower shall promptly pay Lender, upon its
                  demand, such amount as will compensate Lender for any such
                  cost, which determination may be based upon Lender's
                  reasonable allocation of the aggregate of such costs
                  resulting from such events. In the event any such cost is
                  a continuing cost, a fee payable to Lender may be imposed
                  upon Borrower periodically for so long as any such cost is
                  deemed applicable by Lender, in an amount determined by
                  Lender to be necessary to compensate Lender for any such
                  cost. The determination by Lender of the existence and
                  amount of any such cost shall, in the absence of manifest
                  error, be conclusive.


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SECTION 3. Representations, Warranties and General Covenants. In order to
induce Lender to enter into this Agreement, Borrower represents, warrants
and covenants the following:

3.1.          Organization and Qualification. It is and will continue to be a
              corporation duly organized, validly existing and in good standing
              under the laws of the state of its incorporation and is and will
              continue to be duly qualified and licensed to do business in each
              other state in which it is required to be so qualified and/or
              licensed.

3.2.          Corporate Records. The Certificate of Incorporation and all
              amendments thereto of the Borrower have been duly filed and are in
              proper order. All books and records of Borrower, including but not
              limited to its bylaws, minute books and books of account, are
              accurate and up to date and will be so maintained.

3.3.          Power and Authority. Borrower has the power to execute, deliver
              and carry out the terms of this Agreement, the Note, and all other
              documents evidencing, securing and guarantying the Loan (the "Loan
              Documents") and to incur the Obligations and each has taken all
              necessary action to authorize the execution, delivery and
              performance of the Loan Documents.

3.4.          No Legal Bar. The execution and delivery of the Loan Documents
              and compliance by Borrower with the terms and provisions
              thereof will not violate any provision of any existing law or
              regulation or any writ or decree of any court or governmental
              instrumentality, or any agreement or instrument to which it is
              a party or which is binding upon it or its assets, and will not
              result in the creation or imposition of any lien, security
              interest, charge or encumbrance of any nature whatsoever upon
              or in any of its assets, except as contemplated by the Loan
              Documents; and no consent of any other party, and no consent,
              license, approval or authorization of or registration or
              declaration with any governmental bureau or agency, is required
              in connection with the execution, delivery, performance,
              validity and enforceability of any of the Loan Documents.

3.5.          Title. Borrower has good and marketable title to all of its
              property and assets (the "Property").

3.6.          No Material Litigation. There is no material litigation or
              administrative proceeding of or before any governmental body which
              is presently pending-or, to the knowledge of Borrower, threatened
              against it or any of its Property.

3.7.          No Default. Borrower is not in default with respect to the payment
              or performance of any of its Obligations or in the performance of
              any covenants or conditions to be performed by it pursuant to the
              terms and provisions of any indenture, agreement or instrument to
              which it is a party or by which it is bound, and Borrower has not
              received a notice of default thereunder.


                                       -5-


<PAGE>


3.8.          Compliance with Laws. Borrower has complied with and will continue
              to comply with all applicable statutes and regulations of the
              United States of America, and all states, counties, municipalities
              and agencies of any governmental authority thereof.

3.9.          Taxes. Borrower has filed or caused to be filed or obtained
              extensions for the filing of, and will continue to file and
              cause to be filed, all federal, state and local tax returns
              required by law to be filed, and has paid and will continue to
              pay all taxes shown to be due and payable on such returns or on
              any assessment made against it, except if being contested in
              good faith and adequate provision has been made therefor on
              Borrower's books of account. No claims are being asserted with
              respect to such taxes which are not reflected in the financial
              statements which have been furnished by Borrower to Lender.

3.10.         Financial Condition. Borrower has submitted to Lender various
              financial statements and information as of September 30, 1996.
              Borrower represents that all of such financial information is
              true and correct; that such financial information fairly
              presents the financial condition and results of operations of
              Borrower as of the dates thereof and for the periods indicated
              therein; that such financial statements have been prepared in
              accordance with GAAP and practices consistently maintained
              throughout the periods involved; and that, as of the date of
              such financial information, there were no material unrealized
              or anticipated losses from any unfavorable commitments of
              Borrower and that there has been no material adverse change in
              the business or Property or in the condition, financial or
              otherwise, of Borrower from that set forth in such financial
              statements. Since the date of such financial statements there
              has not occurred any material adverse change in the condition,
              financial or otherwise, business, operations, properties or
              prospects of Borrower.

3.11.         Accuracy of Representations. No representation, warranty or
              statement by Borrower contained in any Loan Document or
              certificate or other document furnished or to be furnished by
              Borrower pursuant to this Agreement or in connection with the
              transactions contemplated under this Agreement, contains, or at
              the time of delivery will contain, any untrue statement of
              material fact or omits or will omit to state a material fact
              necessary to make it not misleading.

3.12.         Trade Names. Borrower operates its business under its name as
              set forth in this Agreement and has no other trade names.

3.13.         Collective Bargaining Agreements. Borrower is not a party to
              any collective bargaining agreements.

3.14.         Saleable Value of Assets. The fair saleable value of the assets
              of Borrower, after giving effect to the transactions
              contemplated by the Loan Documents, will not be

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              in excess of its debts (including contingent, subordinated,
              unmatured and unliquidated liabilities).

3.15.         Sufficient Cash Flow. Borrower has, and after giving effect to
              the transactions contemplated by the Loan Documents will have,
              sufficient cash flow to continue to operate its business in the
              ordinary course as heretofore conducted, make the payments
              called for by the Loan Documents and pay all other debts,
              including but not limited to payments under the Note, supplier
              payments, pension and other employee benefit plan liabilities,
              business expenses and taxes, as the same shall become due.

3.16.         No Hindrance. Borrower has no intent to hinder, delay or
              defraud any entity to which it is or will become indebted.

3.17.         Ability to Pay Debts. Borrower, after giving effect to the
              transactions contemplated by the Loan Documents, does not intend
              to incur nor does it believe that it will incur debts beyond its
              ability to pay as they become due.

3.18.         Ownership of Property. Borrower does not have in its possession
              any personal property of which it is not the actual owner,
              except as described on SCHEDULE 3.19.

3.19.        Subsidiaries and Affiliates. Borrower has no subsidiaries or
             affiliates except as described on SCHEDULE 3.20 attached hereto.

3.20.        Pension Plans.

             a.   No event, including but not limited to any "reportable
                  event", as that term is defined in Section 4043 of ERISA
                  exists in connection with any of its Plans and any
                  entities related to it under Section 414(b,), (c), (m),
                  (n) or (o) of the Code has occurred which might constitute
                  grounds for termination of any such Plan by the Pension
                  Benefit Guaranty Corporation (the "PBGC"), or for the
                  appointment by the appropriate United States District
                  Court of a trustee to administer any such Plan. A list of
                  all of its Plans are attached hereto on SCHEDULE 3.21a;

             b.   No "prohibited transaction" within the meaning of Section 406
                  of ERISA or Section 4975 of the Code exists or will exist upon
                  the execution and delivery of this Agreement and the other
                  Loan Documents, or the performance by the Borrower of its
                  duties and obligations hereunder and thereunder;

             c.   It has no unfunded liability in contravention of ERISA and the
                  Code;

                                       -7-


<PAGE>


             d.   Each of the Plans complies currently, and has complied in the
                  past, both as to form and operation, with its terms and with
                  the provisions of the Code and ERISA, and all applicable
                  regulations thereunder and all applicable rules issued by the
                  Internal Revenue Service, U.S. Department of Labor and the
                  PBGC and as such, is and remains a "qualified" plan under the
                  Code;

             e.   No actions, suits or claims are pending (other than routine
                  claims for benefits) against any Plan or the assets of any
                  Plan;

             f.   It has performed all obligations required to be performed by
                  it under any Plan set forth in SCHEDULE 3.21a and it is not in
                  default or in violation of any Plan, and has no knowledge of
                  any such default or violation by any other party to any such
                  Plans;

             g.   It has incurred no liability to the PBGC or to participants or
                  beneficiaries on account of any termination of a Plan subject
                  to Title IV of ERISA, no notice of intent to terminate a Plan
                  has been filed by (or on behalf of) it pursuant to Section
                  4041 of ERISA and no proceeding has been commenced by the PBGC
                  pursuant to Section 4042 of ERISA;

             h.   It is not subject to any reporting or disclosure provisions of
                  the Securities Act of 1933 or the Securities Exchange Act of
                  1934 with respect to any Plan

3.21.       Environmental Matters. Except as described on SCHEDULE 3.22
            attached hereto:

            a.    It has obtained all permits, licenses and other
                  authorizations which are required under all Environmental
                  Laws. It is in compliance with the terms and conditions of
                  all such permits, licenses and authorizations, and is, to
                  the best of its knowledge, also in compliance with all
                  other limitations, restrictions, conditions, standards,
                  prohibitions, requirements, obligations, schedules and
                  timetables contained in any applicable Environmental Law
                  or in any regulation, code, plan, order, decree, judgment,
                  injunction, notice or demand letter issued, entered,
                  promulgated or approved thereunder.

            b.    No notice, notification, demand, request for information,
                  citation, summons or order has been issued, no complaint
                  has been filed, no penalty has been assessed and no
                  investigation or review is pending or threatened by any
                  governmental or other entity with respect to any alleged
                  failure by it to have any permit, license or authorization
                  required in connection with the conduct of its business or
                  with respect to any Environmental Laws, including without
                  limitation, Environmental Laws relating to the


                                       -8-

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                   generation, treatment, storage, recycling, transportation,
                   disposal or release of any Hazardous Materials.

            c.     There are no liens or encumbrances arising under or pursuant
                   to any Environmental Laws on any of the property or
                   properties owned by it, and no governmental actions have been
                   taken or are in process which could subject any of such
                   properties to such liens or encumbrances or, as a result of
                   which it would be required to place any notice or restriction
                   relating to the presence of Hazardous Materials at any
                   property owned by it in any deed to such property.

SECTION 4. Affirmative Covenants. Borrower covenants and agrees that, so long
as any of the Obligations shall remain outstanding, it will perform and
observe each and all of the covenants and agreements herein set forth.

4.1.        Payments Under this Agreement and the other Loan Documents. It will
            make punctual payment of all monies and will faithfully and fully
            keep and perform all of the terms, conditions, covenants and
            agreements contained on its part to be paid, kept or performed
            hereunder, and will be bound in all respects as debtor under this
            Agreement and the other Loan Documents.

4.2.        Information Access to Books, and Inspection. It will furnish to
            Lender such information regarding its business affairs and financial
            condition as Lender may reasonably request and give any
            representative of Lender access during normal business hours to, and
            permit him/her to examine and copy, and make extracts from, any and
            all books, records and documents in its possession relating to its
            affairs and to inspect any of the Property.

4.3.        Payment of Liabilities. It will pay and discharge at or before their
            maturity all taxes, assessments, rents, claims, debts and charges,
            except where the same may be contested in good faith and will
            maintain, in accordance with GAAP, appropriate reserves for the
            accrual of any of the same.

4.4.        Existence, Properties, Insurance. It will do or cause to be done
            all things necessary to preserve and keep in full force and
            effect its corporate or partnership existence, as the case may
            be, its rights and franchises, and will comply with all laws
            applicable thereto; and will at all times maintain, preserve and
            protect all franchises, patents, and trade names and will
            preserve all of the remainder of its Property used or useful in
            the conduct of its business and will keep the same in good
            condition and repair (normal wear and tear and obsolescence
            excepted), and from time to time will reasonably make, or cause
            to be made, all needful and proper repairs, renewals,
            replacements, betterments and improvements thereto, and will pay
            or cause to be paid, except when the same may be contested in
            good faith, all rent due on premises where any Property is held
            or may be held, so that the

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             business carried on in connection therewith may be continuously
             conducted. Borrower will have and maintain insurance at all times
             with respect to all Property against risks of fire (including
             so-called extended coverage), theft and such risks as Lender may
             reasonably require containing such terms, in such form, and for
             such periods, and written by such companies as may reasonably be
             satisfactory to Lender, such insurance to be payable to Lender and
             Borrower as their interests may appear; each policy of insurance
             shall have a loss payee endorsement providing:

            a.    That, if the policy is cancelled at any time by the insurance
                  carrier, in such case the policy shall continue in force for
                  the benefit of Lender for not less than thirty (30) days after
                  written notice of cancellation to Lender from the insurance
                  carrier; and

            b.    That the policy will not be reduced or cancelled at the
                  request of the insured nor will said loss payee endorsement be
                  amended or deleted without thirty (30) days' prior written
                  notice to Lender from the insurance carrier.

             Borrower will furnish Lender with certificates or other evidence
             satisfactory to Lender of compliance with the foregoing insurance
             provisions. Borrower will also at all times maintain necessary
             workers' compensation insurance and such other insurance as may be
             required by law or as may be reasonably required in writing by
             Lender.

4.5.        Notices. It will promptly give notice in writing to Lender of:

            (a) the occurrence of any event which constitutes or which with
            notice or lapse of time, or both, would constitute an Event of
            Default under this Agreement or any of the other Loan Documents;
            (b) the occurrence of any material adverse change in its
            business, properties or its condition or operations, financial or
            otherwise, setting forth a description of such material adverse
            change; and (c) any court or governmental orders, notices,
            claims, investigations, litigation and proceedings received by it
            in which the aggregate amount involved is $250,000 or more and
            not covered by insurance, and of any material dispute which may
            exist between it and any governmental regulatory body or any
            other party.

4.6.        Financial Statements; Notice of Default. The Borrower shall
            deliver or cause to be delivered to Lender

            a.    as soon as available and in any event within forty-five (45)
                  days after the end of each of its first, second and third
                  fiscal quarters, a balance sheet of the Borrower as of the
                  close of each such fiscal quarter and statements of income and
                  retained earnings for that portion of the fiscal year-to-date
                  then ended, which shall be prepared in conformity with GAAP,
                  applied on a


                                      -10-

<PAGE>

                  basis consistent with that of the preceding period, and which
                  shall be certified by the president or Chief Financial
                  Officer of the Borrower as being accurate and fairly
                  presenting the financial condition of the Borrower.

            b.    as soon as available and in any event within ninety (90)
                  days after the close of each fiscal year of the Borrower,
                  audited financial statements including a balance sheet as
                  of the close of such fiscal year and statements of income
                  and retained earnings and source and application of funds
                  for the year then ended, all on a comparative basis with
                  corresponding statements for the preceding fiscal year and
                  prepared in conformity with generally accepted accounting
                  principles, applied on a basis consistent with that of the
                  preceding year, and accompanied by an unqualified opinion
                  of such accountants and a written statement from such
                  accountants stating that they have reviewed such financial
                  statements and the financial covenants set forth herein and
                  have found no evidence of an Event of Default having
                  occurred or of an event which with passage of time and/or
                  giving of notice would constitute an Event of Default
                  having occurred.

            c.    together with the statements referred to in sub-paragraphs (i)
                  and (ii) above, a written statement from the President or
                  Chief Financial Officer of the Borrower certifying that there
                  exists no Event of Default by Borrower in the performance of
                  any obligations to Lender under the Loan Documents.

            d.    from time to time, promptly upon Lender's written request,
                  such other information about the financial condition and
                  operations of Borrower as Lender may reasonably request.

            e.    promptly on becoming aware of any Event of Default, or any
                  event but for the giving of notice or the passage of time
                  would constitute an Event of Default, notice thereof, in
                  writing.

4.7.        Pension Plans. It shall do all acts, including, but not limited to,
            making all contributions necessary to maintain compliance with ERISA
            and the Code, and agrees not to terminate any such Plan in a manner
            or do or fail to do any act which could result in the imposition of
            a lien on any of its properties pursuant to Section 4068 of ERISA;

4.8.        Reports. Borrower shall deliver to Lender:

            a.    as soon as available and in any event within forty-five (45)
                  days after the end of each fiscal quarter of the Borrower, a
                  report, in form satisfactory to Lender, setting forth the
                  calculations of, and information as to compliance


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<PAGE>

                 with, the financial covenants of the Borrower contained in
                 SECTION 5.8 of this Agreement, certified by the President or
                 Chief Financial Officer of the Borrower to be complete and
                 correct;

            b.    as soon as available and in any event within a reasonable time
                  after the close of each fiscal year of Borrower, copies of the
                  portions of any and all auditors' letters, if any, to Borrower
                  regarding any material changes in the accounting practices and
                  control procedures used by Borrower;

SECTION 5. Negative Covenants. So long as any Obligations remain outstanding
and unpaid, Borrower covenants and agrees that it will not without the
express written consent of Lender:

5.1.        Limitation on Liens. Incur or permit to exist any liens, mortgages,
            security interests, pledges, charges or other encumbrances against
            any of its property or assets, whether now owned or hereafter
            acquired (including, without limitation, any lien or encumbrance
            relating to any response, removal or clean-up of any toxic
            substances or hazardous wastes) which in the aggregate exceed
            $250,000, except: (a) liens, mortgages, security interests, charges
            or other encumbrances in favor of Lender or specifically permitted
            in writing by Lender; (b) pledges or deposits in connection with or
            to secure workers' compensation or unemployment insurance; and (c)
            tax liens which are being contested in good faith with the prior
            written consent of Lender and against which, if requested by
            Lender, Borrower shall maintain reserves in amounts and in form
            (book, cash, bond or otherwise) satisfactory to Lender.

5.2.        Covenant to Secure Equally and Ratably. Permit any other
            indebtedness incurred before or after the date hereof to be secured
            by any asset of Borrower without Lender's prior written consent,
            except liens securing indebtedness to any seller incurred in
            connection with the purchase of personal property for the business
            of such Borrower which is secured only by the property so financed.

5.3.        Financial Covenants. Unless Lender otherwise consents in writing:

            a.    Current Ratio. Borrower shall not permit its Current Ratio
                  to be less than 1.00 to 1.00 at any time.

            b.    Ratio of Total Liabilities to Net Worth. Borrower shall not
                  permit the ratio of its Total Liabilities to Net Worth to
                  exceed .75 to 1.0 at any time.

            c.    Net Worth. Borrower shall not permit its Net Worth to be less
                  than $25,000,000 at any time.


                                      -12-

<PAGE>

            d.    The financial covenants contained above shall be calculated in
                  accordance with generally accepted accounting standards.

SECTION 6. Default.

6.1.        The occurrence of any of the following events will constitute an
            Event of Default under this Agreement:

            a.    The failure to pay any installment of principal and/or
                  interest due under the Loan or any fee when due and payable.

            b.    The failure to pay taxes, if any, due on any indebtedness
                  under the Loan or any tax or assessment upon any collateral
                  securing the Obligations, on or before the same shall become
                  due and payable.

            c.    The failure by Borrower to observe or perform any other
                  covenant contained in this Agreement or in any of the other
                  Loan Documents.

            d.    The occurrence of an Event of Default under any of the other
                  Loan Documents.

            e.    The filing by or against Borrower of any petition,
                  arrangement, reorganization, or the like under any
                  insolvency or bankruptcy law, or the adjudication of
                  Borrower as a bankrupt (and if such filing is involuntary,
                  the failure to have same dismissed within sixty (60) days
                  from the date of filing), or the making of an assignment
                  for the benefit of creditors, or the appointment of a
                  receiver for any part of Borrower's properties or the
                  admission in writing by Borrower of its inability to pay
                  its debts as they become due.

            f.    The breach in any material respect of any warranty or the
                  untruth or inaccuracy in any material respect of any
                  representation of Borrower contained in the Loan Documents or
                  made or deemed made in connection with the making of the Loan
                  hereunder.

            g.    The occurrence of a default beyond any applicable grace period
                  under or demand for the payment of any other note or
                  obligation of Borrower.

            h.    The failure by Borrower to make payment on any obligation for
                  borrowed money or for the deferred purchase price of property
                  or services due to any party other than Lender, beyond any
                  grace period provided with respect thereto, or upon demand, or
                  the failure to perform any other term, condition, or covenant
                  contained in any agreement under which any such


                                      -13-

<PAGE>


                    obligation is created, the effect of which default is to
                    cause such obligation to become due and payable prior to its
                    date of maturity.

              i.    The dissolution or termination of existence of Borrower.

              j.    The passage or enforcement of any federal, state, or local
                    law or the rendition of a final decision of any court (other
                    than a law or decision with respect to a tax upon the
                    general revenues of Lender) in any way directly changing or
                    affecting the Loan or lessening the net income thereon in a
                    fashion which is not corrected or reimbursed by Borrower.

              k.    The passage or enforcement of any federal, state, or local
                    law or the rendition of a final decision of any court in any
                    way impairing Lender's ability to charge and collect the
                    interest stated in the Note, including without limitation,
                    the ability to vary the interest payable under the Note in
                    accordance with its terms.

              l.    A judgment or judgments for the payment of money aggregating
                    more than $250,000 or more shall be rendered against
                    Borrower and any such judgment shall remain unsatisfied and
                    in effect for a period of thirty (30) consecutive days
                    without a stay of execution.

              m.    The occurrence of a material adverse change in any business,
                    properties or the condition or operations, financial or
                    otherwise, of Borrower.

6.2.          Acceleration. Upon the happening of any Event of Default
              specified above, at Lender's option, the entire unpaid balance
              owed under the Loan, the Note and the Loan Documents and under
              any other note or other documents evidencing the same, plus any
              other sums owed hereunder, shall, at Lender's option, become
              and shall thereafter be immediately due and payable without
              presentment, demand, protest, notice of protest, or other
              notice of dishonor of any kind, all of which are hereby
              expressly waived by Borrower. Failure to exercise such option
              shall not constitute a waiver of the right to exercise the same
              in the event of any subsequent default. Upon the occurrence of
              any Event of Default, without in any way affecting Lender's
              other rights and remedies, or after maturity or judgment, the
              interest rate applicable to the Loan shall automatically change
              without notice to a floating rate per annum equal to two
              percentage points (2%) above the otherwise then applicable rate.

6.3.          Rights of Lender. In the event of the occurrence of an Event of
              Default (a) Lender will have the right to enforce all of its
              rights under the Loan Documents and (b) Lender shall have, in
              addition to all other rights provided herein, the rights and
              remedies provided by law and (c) Lender shall make no further
              advances under the Note. Failure by Lender to exercise any right,
              remedy or option under this


                                      -14-


<PAGE>


              Agreement or any of the other Loan Documents or in any other
              agreement between Borrower and Lender, or delay by Lender in
              exercising the same will not operate as a waiver by Lender.
              Neither Lender nor any party acting as Lender's attorney pursuant
              to this Agreement shall be liable for any error of judgment or
              mistake of fact or law. Lender's rights and remedies under this
              Agreement will be cumulative and not exclusive of any other right
              or remedy which Lender may have.

SECTION 7. Miscellaneous.

7.1.          Indemnification. In consideration of Lender's execution and
              delivery of this Agreement and Lender's making of the Loan
              hereunder and in addition to all other obligations of Borrower
              under this Agreement, Borrower hereby agree to defend, protect,
              indemnify and hold harmless Lender, its successors, assigns,
              officers, directors, employees and agents (including, without
              limitation, those retained in connection with the transactions
              contemplated by this Agreement) (collectively, the "Indemnitee")
              from and against any and all actions, causes of action, suits,
              claims, losses, costs, penalties, fees, liabilities and damages
              and expenses in connection therewith (irrespective of whether
              any such Indemnitee is a party to any action for which
              indemnification hereunder is sought), and including reasonable
              attorneys' fees and disbursements (the "Indemnifiable
              Liabilities") incurred by the Indemnitee or any of them as a
              result of; or arising out of, or relating to (i) the execution,
              delivery, performance or enforcement of this Agreement and the
              other Loan Documents and any instrument, document or agreement
              executed pursuant hereto to any of the Indemnitee; (ii) Lender's
              status as lender to, or creditor of, Borrower; (iii) the
              operation of Borrower's business from and after the date
              hereof; or (iv) the enforcement of Lender's rights under the
              Loan Documents and/or the collection of the Obligations,
              provided that Borrower shall not be required to indemnify
              Indemnitee for any Indemnifiable Liabilities resulting from the
              gross negligence or willful misconduct of Lender or any of the
              other Indemnities in the collection of the Loan and in the
              liquidation of the collateral thereafter. To the extent that
              the foregoing undertaking by Borrower may be unenforceable for
              any reason, Borrower shall make the maximum contribution to the
              payment and satisfaction of each of the Indemnifiable
              Liabilities which is permissible under applicable law.

7.2.          Setoff. In addition to and not in limitation of the above,
              with respect to any deposits or Property of Borrower in
              Lender's possession or control, now or in the future,
              Lender shall have the right, following the occurrence of an
              Event of Default, to setoff all or any portion thereof; at
              any time, against any Obligations hereunder, even though
              unmatured, without prior notice or demand to Borrower.


                                      -15-


<PAGE>


7.3.          WAIVER OF RIGHT TO PREJUDGMENT REMEDY NOTICE AND HEARING. BORROWER
              ACKNOWLEDGES THAT LENDER MAY HAVE RIGHTS AGAINST IT, NOW OR IN
              THE FUTURE, IN ITS CAPACITY AS CREDITOR OR IN ANY OTHER CAPACITY.
              SUCH RIGHTS MAY INCLUDE THE RIGHT TO DEPRIVE BORROWER OF OR AFFECT
              THE USE OF OR POSSESSION OR ENJOYMENT OF BORROWER'S PROPERTY; AND
              IN THE EVENT LENDER DEEMS IT NECESSARY TO EXERCISE ANY OF SUCH
              RIGHTS PRIOR TO THE RENDITION OF A FINAL JUDGMENT AGAINST
              BORROWER, OR OTHERWISE, BORROWER MAY BE ENTITLED TO NOTICE AND/OR
              HEARING UNDER THE CONSTITUTION OF THE UNITED STATES AND/OR STATE
              OF CONNECTICUT, CONNECTICUT STATUTES (TO DETERMINE WHETHER OR NOT
              LENDER HAS PROBABLE CAUSE TO SUSTAIN THE VALIDITY OF LENDER'S
              CLAIM), OR THE RIGHT TO NOTICE AND/OR HEARING UNDER OTHER
              APPLICABLE STATE OR FEDERAL LAWS PERTAINING TO PREJUDGMENT
              REMEDIES, PRIOR TO THE EXERCISE BY LENDER OF ANY SUCH RIGHTS. TO
              THE MAXIMUM EXTENT PERMITTED BY LAW, BORROWER EXPRESSLY WAIVES ANY
              SUCH RIGHT TO PREJUDGMENT REMEDY NOTICE OR HEARING TO WHICH
              BORROWER MAY BE ENTITLED. THIS SHALL BE A CONTINUING WAIVER AND
              REMAIN IN FULL FORCE AND EFFECT SO LONG AS BORROWER ARE OBLIGATED
              TO LENDER.

7.4.          Waiver of Trial by Jury. Borrower hereby waives trial by jury in
              any court and in any suit, action, or proceeding on any matter
              arising in connection with, or in any way related to, this
              Agreement or the other Loan Documents and/or the enforcement of
              the Lender's rights and remedies hereunder or thereunder,
              including, without limitation, tort claims.

7.5.          Additional Waivers. Borrower unconditionally waives to the fullest
              extent permitted by law (a) any requirement of diligence, (b))all
              defenses which may now or hereafter exist by virtue of any statute
              of limitations, stay, valuation, moratorium or similar law, except
              the sole defense of payment, (c) any and all claims and
              counterclaims for consequential and/or special damages, and (d)
              all demands upon Borrower and all other formalities the omission
              of any of which, or delay in the performance of which, might, but
              for the provisions of this section, by rule of law or otherwise,
              constitute grounds for relieving or discharging the Borrower in
              whole or in part from any of the Obligations, it being the
              intention of the Borrower that its Obligations shall not be
              discharged, except by performance and then only to the extent of
              such performance.

7.6.          Waivers Made Knowingly. Borrower acknowledges that it makes all
              waivers contained in this Agreement and the other Loan Documents
              knowingly, voluntarily, without duress and only after
              consideration of the ramifications of


                                      -16-


<PAGE>


              these waivers with its attorneys. Borrower further acknowledge
              that Lender has not agreed with or represented to it that the
              provisions of these waivers will not be fully enforced in all
              instances.

7.7.          Consent to Jurisdiction. Borrower agree to submit to jurisdiction
              in the State of Connecticut in any action or proceeding arising
              out of this Agreement or any of the other Loan Documents, and in
              furtherance of such agreement, Borrower hereby agrees and consents
              that without limiting other methods of obtaining jurisdiction,
              jurisdiction over the Borrower in any action or proceeding may be
              obtained within or without the jurisdiction of any court located
              in the State of Connecticut and that any process or notice of
              motion or other application to any such court in connection with
              any such action or proceeding may be served upon the Borrower by
              registered or certified mail to the last known address of the
              Borrower, whether such address is within or without the
              jurisdiction of any such court.

7.8.          No Waiver. No course of dealing between Borrower and Lender and no
              failure to exercise or delay in exercising on the part of Lender
              any right, power or privilege under the terms of this Agreement or
              the other Loan Documents shall operate as a waiver thereof; nor
              shall any single or partial exercise of any right, power or
              privilege hereunder or thereunder preclude any other or further
              privilege. The rights and remedies provided herein or in any other
              agreement are cumulative and not exclusive or in derogation of any
              rights or remedies provided in and thereof, by law or otherwise.

7.9.          Cross-Default. Borrower acknowledge and agree that a default under
              any one of the Loan Documents shall constitute a default under
              each of the other Loan Documents.

7.10.         Survival of Agreements. All agreements, representations and
              warranties made herein, in any agreement and in any statements,
              notices, invoices, certificates, schedules, documents or other
              instruments delivered to Lender in connection with this Agreement
              or any other agreement shall survive the making of the Loan and
              advances hereunder.

7.11.         Further Documents. Borrower agrees that, at any time or from time
              to time upon written request of Lender, it will execute and
              deliver such further documents and do such other acts and things
              as Lender may reasonably request in order to fully effect the
              purposes of this Agreement and the other Loan Documents.

7.12.         Entire Agreement. This Agreement and the documents referred to
              herein constitute the entire agreement of the parties and may not
              be amended orally and shall be construed and interpreted in
              accordance with the laws of the State of Connecticut, including
              its conflict of laws principles.


                                      -17-


<PAGE>


7.13.         Successors. All rights of Lender hereunder shall inure to the
              benefit of its successors and assigns, and all Obligations of
              Borrower shall bind its successors and assigns.

7.14.         Payments. The acceptance of any check, draft or money order
              tendered in full or partial payment of any Obligation hereunder is
              conditioned upon and subject to the receipt of final payment in
              cash.

7.15.         Schedules. All schedules referred to herein and annexed hereto are
              hereby incorporated into this Agreement and made a part hereof.

7.16.         Acknowledgment of Copy, Use of Proceeds. Borrower acknowledges
              receipt of copies of the Note and attests, represents and warrants
              to Lender that advances made under the Loan are to be used for
              general commercial purposes and that no part of such proceeds will
              be used, in whole or in part, directly or indirectly, for the
              purpose of purchasing or carrying any "margin security" or "margin
              stock" as such terms are defined in Regulation U of the Board of
              Governors of the Federal Reserve System.

7.17.         Descriptive Headings. The descriptive headings of the several
              sections of this Agreement are inserted for convenience only and
              shall not be deemed to affect the meaning or construction of any
              of the provisions hereof.

7.18.         Notices. Any written notice required or permitted by this
              Agreement may be delivered by depositing it in the U.S. mail,
              postage prepaid, or by telegraph, charges prepaid, or facsimile
              addressed to Borrower or Lender at the addresses set forth at the
              beginning of this Agreement. If any notice is sent to Lender
              pursuant to this paragraph, it should be sent to the attention of:
              Robert Shettle.

7.19.         Severability. If any provision of this Agreement or application
              thereof to any person or circumstance shall to any extent be
              invalid, the remainder of this Agreement or the application of
              such provision to persons, entities or circumstances other than
              those as to which it is held invalid, shall not be affected
              thereby and each provision of this Agreement shall be valid and
              enforceable to the fullest extent permitted by law.

7.20          Commitment Fee. Borrower agrees to pay to Lender a commitment fee
              payable on a quarterly basis equal to .25% of the amount of the
              Loan.


                                      -18-

<PAGE>

In Witness Whereof, the parties have caused this Agreement to be duly executed
and delivered by the proper and duly authorized officers as of the date and year
first above written.


WITNESS:

---------------------------            FLEET NATIONAL BANK

/s/ IRENE FRANKLIN                     By: /s/ MATT HUMMELL
---------------------------                -----------------------------
                                       Title: Vice President



/s/ MICHAEL E. BIELEWICZ               ZYGO CORPORATION
---------------------------

                                       By: /s/ MARK J. BONNEY
                                           -----------------------------
                                           Title: Vice President
---------------------------


STATE OF CONNECTICUT )
                     )ss.:
COUNTY OF HARTFORD   )

The foregoing instrument was acknowledged before me this 4th day of June, 1997,
by Irene Franklin, a employee of FLEET NATIONAL BANK, a national banking
association, on behalf of the Lender.

                                       /s/  IRENE FRANKLIN
                                       ----------------------------------
                                       Commissioner of the Superior Court
                                       Notary Public
                                       My Commission Expires: January 31, 2000


STATE OF CONNECTICUT )
                     )ss.:
COUNTY OF HARTFORD   )

The foregoing instrument was acknowledged before me this 3rd day of June,
1997, by Mark B. Bonney, Vice President of ZYGO
CORPORATION, a Delaware corporation, on behalf of the corporation.

                                       /s/  JOYCE A. GOLDBERG
                                       ----------------------------------------
                                       Commissioner of the Superior Court
                                       Notary Public
                                       My Commission Expires: December 31, 2001


                                      -19-

<PAGE>

                                PROMISSORY NOTE
                                ---------------

$3,000,000.00                                             Hartford, Connecticut
                                                          June 4, 1997

FOR VALUE RECEIVED, the undersigned, ZYGO CORPORATION, a Delaware corporation
located at Laurel Brook Road, Box 448, Middlefield, Connecticut 06455-0448 (the
"Borrower"), hereby promises to pay to the order of FLEET NATIONAL BANK, a
national banking association, (the "Lender"), at its office at 777 Main Street
Hartford, Connecticut 06115 or at such other place as the holder hereof may
designate, ON DEMAND the principal amount advanced hereunder and remaining
unpaid, up to a maximum amount of THREE MILLION AND NO/100 DOLLARS
($3,000,000.00) (the "Principal Amount") in lawful money of the United States,
together with interest on the Principal Amount, beginning on the date hereof,
before and after maturity or judgment, at a per annum rate determined as
provided below.

     1. Interest Rate: Each advance under this Note (each a "Loan Advance")
shall bear interest at a per annum rate equal to either (a) a floating rate
equal to Lender's Prime Rate (as hereinafter defined) or (b) a fixed rate equal
to sixty (60) basis points above the LIBOR Rate (as determined for each Interest
Period applicable thereto) for available Interest Periods of thirty (30), sixty
(60) or ninety (90) days. The Borrower shall elect either option (a) or (b) as
provided below.

     2. Requests for Advances: Whenever Borrower desires an advance, Borrower
shall notify Lender (which notice shall be irrevocable) by telephone, facsimile
or in writing, of the desired borrowing. Such notice (the "Notice of Borrowing")
shall specify the date of the proposed borrowing, the amount requested, whether
the advance shall be a Prime Rate Loan or a LIBOR Rate Loan, and, if a LIBOR
Rate Loan, the duration of the initial available Interest Period. Each Notice of
Borrowing for advances which are Prime Rate Loans must be received by Lender no
later than 11:00 a.m., Hartford, Connecticut time on the day such borrowing is
requested, and each Notice of Borrowing for advances which are LIBOR Rate Loans
must be received by Lender no later than 10:00 a.m., Hartford, Connecticut time
at least three (3) Business Days' prior to the day such borrowing is requested.
Any Notice of Borrowing that is not in writing shall be followed by a written
confirmation by the Borrower, provided that if such written confirmation differs
in any respect from the action taken by Lender, the records of Lender shall
control, absent manifest error. Lender shall enter each Loan Advance as a debit
on a loan account maintained by Borrower with Lender (the "Loan Account").
Lender may also record in the Loan Account, in accordance with customary banking
procedures, all fees, accrued and unpaid interest, late fees, usual and
customary bank charges for the maintenance and administration of accounts
maintained by Borrower and other fees and charges which are properly chargeable
to Borrower in connection with the Loan Advances and all payments, subject to
collection, made by Borrower on account of or to Lender. Borrower may repay and
reborrow advances that are made under this Note, subject, however, to the
prepayment terms contained below. Borrower shall not have more than three (3)
LIBOR Rate Loans outstanding at any


<PAGE>

one time. Borrower's right to request advances under this Note shall terminate
on the Termination Date. Advances that are LIBOR Rate Loans shall be in the
minimum amount of $l00,000 each.

     3. Election and Continuation of Interest Periods. Any Prime Rate Loan shall
continue as a Prime Rate Loan until the Borrower elects to convert it to a LIBOR
Rate Loan as provided below. Any LIBOR Rate Loan may be continued as such upon
the expiration of the then current Interest Period by the Borrower giving
irrevocable written notice to Lender of the duration of the next available
Interest Period to be applicable to any such LIBOR Rate Loan not less than three
(3) Business Days prior to the last Business Day of the then current Interest
Period with respect to such LIBOR Rate Loan, provided that no LIBOR Rate Loan
may be continued as such: (i) at a time when any Event of Default (or event or
condition which would constitute an Event of Default but for the giving of
notice or passage of time or both) has occurred and is continuing and (ii) after
the date that is thirty (30) days prior to the Termination Date. Unless Borrower
elects to convert to a different interest rate as provided below, if a LIBOR
Rate Loan is not continued as a LIBOR Rate Loan, all as provided above, then any
such loan shall automatically be converted to a Prime Rate Loan on the last day
of the then expiring Interest Period.

     4. Conversion of Loans to a Different Interest Rate. The Borrower may elect
from time to time to convert (a) a LIBOR Rate Loan to a Prime Rate Loan or (b) a
Prime Rate Loan to a LIBOR Rate Loan as provided in this section. Borrower shall
exercise such election by giving the Lender not less than three (3) Business
Days prior irrevocable written notice of such election; provided that any such
conversion of a LIBOR Rate Loan to a Prime Rate Loan shall only be made on the
last Business Day of the then current Interest Period with respect thereto. Any
such notice of conversion to a LIBOR Rate Loan shall specify the length of the
available Interest Period applicable thereto.

     5. Payments of Interest. Interest on this Note shall be calculated on the
basis of a 360 day year and the actual number of days elapsed. Monthly payments
of interest shall be due and payable in arrears on the first day of each month
immediately following each and every month in which a Prime Rate Loan is
outstanding and on the last day of each Interest Period for each and every LIBOR
Rate Loan until this Note is paid in full.

     6. Payments of Principal. If not sooner paid, the aggregate outstanding
Principal Amount of this Note, together with all accrued and unpaid interest
thereon and any other fees or charges then due, shall be due and payable on
demand of the Lender but if not so demanded, all such amounts shall be due and
payable on the Termination Date.

     7. Definitions. As used in this Note and not defined elsewhere in this
Note, the following terms shall have the following meanings:

          a. "Business Day" means any day other than a day on which commercial
     banks in Hartford, Connecticut are required or permitted by law to close.


                                       -2-


<PAGE>

          b. "Interest Period" means with respect to advances bearing interest
     at the LIBOR Rate, an available period of thirty (30), sixty (60) or ninety
     (90) days, provided that:

               (1) if any Interest Period would otherwise end on a day that is
          not a Business Day, such Interest Period shall end on the immediately
          preceding Business Day;

               (2) any Interest Period that begins on the last Business Day of a
          calendar month (or on a day for which there is no numerically
          corresponding day in the calendar month at the end of such Interest
          Period) shall end on the last Business Day of a calendar month; and

               (3) any Interest Period that would otherwise extend beyond the
          Termination Date shall end on the Termination Date.

          c. "LIBOR Rate" means, with respect to any LIBOR Rate Loan for each
     applicable Interest Period, the rate per annum determined by the Lender to
     be equal to the quotient of (a) the London Interbank Offered Rate for such
     LIBOR Rate Loan for such Interest Period, divided by (b) one (1) minus the
     Reserve Percentage for such Interest Period, expressed as follows:

          LIBOR Rate = London Interbank Offered Rate
                       -----------------------------
                         1 - Reserve Percentage

          d. "LIBOR Rate Loan" means an advance that bears interest at a rate
     equal to the LIBOR Rate plus sixty (60) basis points.

          e. "London Interbank Offered Rate" means, with respect to any
     applicable Interest Period for a LIBOR Rate Loan, the rate per annum at
     which the Eurodollar office of the Lender is offered, in the London
     interbank Dollar deposits market, at or about 11:00 a.m. London time, two
     (2) business days prior to the first day of such Interest Period, Dollar
     deposits, for a period, and in an amount, comparable to such Interest
     Period and principal amount of the LIBOR Rate Loan which shall be made by
     the Lender and outstanding during such Interest Period.

          f. "Prime Rate" means the rate of interest announced from time to time
     by Lender at its office in Hartford, Connecticut as its prime rate. Such
     Prime Rate may not be the lowest or best rate that is made available by
     Lender to its commercial borrowers.

          g. "Prime Rate Loan" means an advance that bears interest at a rate
     equal to Lender's Prime Rate. The interest rate on each Prime Rate Loan
     shall change, without notice to Borrower, each time that Lender's Prime
     Rate changes so that the rate of interest on a Prime Rate Loan is at all
     times equal to Lender's Prime Rate.

          h. "Reserve Percentage" means the maximum marginal percentage as
     prescribed by the Board of Governors of the Federal Reserve System (or any
     successor) for determining the reserve requirement for Lender in respect of
     eurodollar deposits having a maturity equal to the

                                      -3-


<PAGE>

Interest Period as the Borrower may elect pursuant to the terms of this Note.
With respect to the LIBOR Rate, any change in the interest rate because of a
change in the Reserve Percentage shall become effective, without notice or
demand, on the date on which such change in the Reserve Percentage becomes
effective.

          i. "Termination Date" means November 26, 1997.

     8. Illegality. Notwithstanding any other provisions hereof, if any
applicable law or governmental regulation, guideline, order or directive, or any
change therein or in the interpretation or application thereof by any
governmental authority charged with the interpretation or the administration
thereof (whether or not having the force of law) shall make it unlawful for the
Lender to make or maintain LIBOR Rate Loans as contemplated by this Note: (i)
the obligation of the Lender to continue LIBOR Rate Loans shall forthwith be
cancelled, and (ii) such amounts then outstanding shall be automatically
converted, without notice, to Prime Rate Loans on the last day of the then
current Interest Period or within such earlier time as required by law. If any
such conversion of LIBOR Rate Loans is made on a day that is not the last
Business Day of the then current Interest Period applicable thereto, Borrower
shall pay the Lender such amount or amounts required pursuant to Section 13
below.

     9. Basis for Determining LIBOR Inadequate or Unfair. In the event that the
Lender shall have determined (which determination, absent manifest error, shall
be conclusive and binding upon Borrower) that (i) by reason of circumstances
affecting the Interbank LIBOR market, adequate and reasonable means do not exist
for determining the LIBOR Rate, or (ii) Dollar deposits in the relevant amount
and for the relevant maturity are no longer available to the Lender in the
Interbank LIBOR market, or (iii) the continuation of LIBOR Rate Loans has been
made impractical or unlawful by the occurrence of a contingency that materially
and adversely affects the Interbank LIBOR market, or (iv) the LIBOR Rate will
not adequately and fairly reflect the cost to the Lender of maintaining LIBOR
Rate Loans, or (v) the LIBOR Rate shall no longer represent the effective cost
to the Lender of U.S. Dollar deposits in the relevant market for deposits in
which it regularly participates, the Lender shall give the Borrower notice of
such determination as soon as practicable. If such notice is given all LIBOR
Rate Loans shall be automatically converted, without notice, to Prime Rate Loans
effective on the last Business Day of the then current Interest Period
applicable thereto. Until such notice has been withdrawn, the LIBOR Rate shall
not be continued.

     10. Costs and Expenses. The Borrower shall pay all taxes levied or assessed
on this Note or the debt evidenced hereby against the Lender, together with all
costs, expenses and attorneys' and other professional fees incurred in any
action to collect and/or enforce this Note or to enforce the Loan Agreement
between Borrower and Lender dated the same date as this Note (the "Loan
Agreement") or any other agreement relating to this Note or the Loan Agreement
or any other agreement or in any litigation or controversy arising from or
connected with the Loan Agreement or any other agreement, or this Note.

                                       -4-

<PAGE>

     11. Increased Costs. In the event that applicable law, treaty or regulation
or directive from any government, governmental agency or regulatory authority,
or any change therein or in the interpretation or application thereof, or
compliance by the Lender with any request or directive (whether or not having
the force of law) from any central bank or government, governmental agency or
regulatory authority, shall:

          a. subject the Lender to any tax of any kind whatsoever (except taxes
     on the overall net income of the Lender) with respect to the Loan
     Agreement, this Note or any of the loans made by it, or change the basis of
     taxation of payments to the Lender in respect thereof (except for changes
     in the rate of tax on the overall net income of the Lender);

          b. impose, modify or hold applicable any reserve, special deposit,
     compulsory loan or similar requirements against assets held by, deposits or
     other liabilities in or for the account of, advances, loans or other
     extensions of credit by, or any other acquisition of funds by, any office
     of the Lender, including (without limitation) pursuant to Regulations of
     the Board of Governors of the Federal Reserve System; or

          c. in the opinion of the Lender, cause this Note, any loan made under
     this Note or under the Loan Agreement to be included in any calculations
     used in the computation of regulatory capital standards; or

          d. impose on the Bank any other condition;

and the result of any of the foregoing is to increase the cost to the Lender, by
an amount that the Lender deems to be material, of making, converting into,
continuing and/or maintaining the loans made pursuant to this Note (the "Loans")
or to reduce the amount of any payment (whether of principal, interest or
otherwise) in respect of any of such Loans, then, in any case, the Borrower
shall promptly pay the Lender, upon its demand, such additional amounts
necessary to compensate the Lender for such additional costs or such reduction
in payment, as the case may be (collectively the "Additional Costs"). The Lender
shall certify the amount of such Additional Costs to the Borrower, and such
certification, absent manifest error, shall be deemed conclusive.

     12. Capital Adequacy Protection. If, after the date hereof, the Lender
shall have determined that the adoption of any applicable law, governmental
rule, regulation or order regarding capital adequacy of banks or bank holding
companies, or any change therein, or any change in the interpretation or
administration thereof by any governmental authority, central bank or comparable
agency charged with the interpretation or administration thereof, or compliance
by the Lender with any request or directive regarding capital adequacy (whether
or not having the force of law and whether or not failure to comply therewith
would be unlawful, so long as the Lender believes in good faith that such has
the force of law or that the failure to so comply would be unlawful) of any such
authority, central bank or comparable agency, has or would have the effect of
reducing the rate of return on any of the Lender's capital as a consequence of
the Lender's obligations hereunder to a level below that which the Lender could
have achieved but for such adoption, change or compliance

                                       -5-


<PAGE>

(taking into consideration the Lender's policies with respect to capital
adequacy immediately before such adoption, change or compliance and assuming
that the Lender's capital was fully utilized prior to such adoption, change or
compliance) by an amount deemed by the Lender in its judgment to be material,
then, promptly upon demand, the Borrower shall immediately pay to the Lender,
from time to time as specified by the Lender, such additional amounts as shall
be sufficient to compensate the Lender for such reduced return, together with
interest on each such amount from the date of such specification by the Lender
until payment in full thereof at the highest rate of interest (other than the
default rate of interest) due on the Loans. A certificate of the Lender setting
forth the amount to be paid to the Lender shall, in the absence of manifest
error, be deemed conclusive. In determining such amount, the Lender shall use
any reasonable averaging and attribution methods. The Borrower may, however,
avoid paying such amounts for future rate of return reductions if, within the
maximum borrowings permitted herein, the Borrower borrows such amounts as will
cause the Lender to avoid any such future rate of return reductions which would
otherwise be caused by such changed capital adequacy requirements or the
Borrower agrees to a reduction in the Loans to achieve the same result.

     13. Indemnity. The Borrower agrees to indemnify the Lender and to hold the
Lender harmless from any loss (including any of the additional costs referred to
above and any lost profits) or expense that it may sustain or incur as a
consequence of (i) a default by the Borrower in the payment of the principal of
or interest due on this Note, or (ii) the making of a prepayment of the
Principal Amount bearing interest at the LIBOR Rate on a day which is not the
last day of the then current Interest Period applicable thereto, including, but
not limited to, in each case any such loss or expense arising from the
reemployment of funds obtained by it or from fees, interest or other amounts
payable to terminate the deposits from which such funds were obtained. The
Lender shall prepare a certificate as to any additional amounts payable to it
pursuant to this Section 13, which certificate shall be submitted by the Lender
to the Borrower and shall, absent manifest error, be deemed conclusive.

     14. Lawful Interest. Notwithstanding any provisions of this Note, it is the
understanding and agreement of the Borrower and Lender that the maximum rate of
interest to be paid by the Borrower to the Lender shall not exceed the highest
or the maximum rate of interest permissible to be charged by a commercial lender
such as the Lender to a commercial borrower such as the Borrower under the laws
of the State of Connecticut. Any amount paid in excess of such rate shall be
considered to have been payments in reduction of principal.

     15. Late Charge. Without limiting the Lender's rights and remedies with
respect to the Event of Default that will have occurred, the Borrower hereby
agrees to pay a "late charge" equal to five percent (5%) of any installment of
interest or other amount due to the Lender which is not paid within fifteen (15)
days of the due date and is not due to the Lender's failure to debit Borrower's
account on a timely basis. Thereof to defray the extra expense involved in
handling such delinquent payment.

                                       -6-


<PAGE>

     16. Prepayments.

          a. The Borrower may, at its option and upon two (2) Business Days'
     prior written notice (which notice shall be irrevocable), prepay the
     Principal Amount of a LIBOR Rate Loan or a Prime Rate Loan on the following
     conditions: (a) the Borrower shall pay all accrued interest on the
     Principal Amount being paid to the date of the prepayment and, in the case
     of prepayments in full, all fees, charges, costs, expenses and other
     amounts then due hereunder; and (b) such Principal Amount of a LIBOR Rate
     Loan shall only be prepaid on the last Business Day of the then current
     Interest Period with respect thereto. In its notice, the Borrower shall
     specify the date and amount of the prepayment. In the event that any
     prepayment of the Principal Amount of a LIBOR Rate Loan is required or
     permitted on a date other than the last Business Day of the then current
     Interest Period with respect thereto, the Borrower shall indemnify the
     Lender therefore as provided in this Note.

          b. In the event that Borrower makes a prepayment and does not
     specify in its notice of prepayment whether the prepayment is to be applied
     to a LIBOR Rate Loan or a Prime Rate Loan, then Lender shall apply such
     prepayment in such order as Lender in its sole discretion shall determine.

     17. Events of Default. The Borrower agrees that the occurrence of an Event
of Default under the Loan Agreement shall constitute an Event of Default under
this Note. Reference is hereby made to the Loan Agreement for the other terms
and conditions relating to the loan evidenced by this Note which are
incorporated in this Note by reference. Upon demand of the amounts due hereunder
by the Lender or upon the occurrence of any Event of Default, the availability
of advances hereunder shall, at the option of the Lender, be automatically
terminated and the Lender, at its option, may declare all advances outstanding
hereunder, together with accrued interest thereon and all applicable late
charges, other amounts due under this Note and all other liabilities and
obligations of the Borrower to the Lender to be immediately due and payable,
whereupon the same shall become immediately due and payable; all of the
foregoing without demand, presentment, protest or notice or any kind, all of
which are hereby expressly waived by the Borrower. Failure to exercise such
option shall not constitute a waiver of the right to exercise the same in the
event of any subsequent default. Upon the occurrence of any Event of Default,
without in any way affecting the Lender's other rights and remedies, or after
maturity or judgment, the interest rate applicable to the outstanding principal
balance of this Note shall automatically change without notice to a floating per
annum rate equal to two percentage points (2.0%) above the otherwise applicable
rate.

     18. Lien and Right of Setoff. The Borrower hereby gives the Lender a right
of setoff for all liabilities arising hereunder upon and against all the
deposits, credits and property of Borrower now or hereafter in the possession,
custody, safekeeping or control of the Lender or in transit to it. Lender may,
upon the occurrence of an Event of Default, without notice and without first
resorting to any collateral which may now or hereafter secure this Note, apply
or set off the same, or any part thereof, to any liability of the Borrower, even
though unmatured.

                                       -7-


<PAGE>



     19. No Waiver. Failure by the Lender to insist upon the strict performance
by Borrower of any terms and provisions herein shall not be deemed to be a
waiver of any terms and provisions herein, and the Lender shall retain the right
thereafter to insist upon strict performance by the Borrower of any and all
terms and provisions of this Note or any agreement securing the repayment of
this Note.

     20. Governing Law. This Note shall be governed by the laws of the State of
Connecticut.

     21. Prejudgment Remedy and Other Waivers. THE BORROWER ACKNOWLEDGES THAT
THE LOAN EVIDENCED BY THIS NOTE IS A COMMERCIAL TRANSACTION AND WAIVES ITS RIGHT
TO NOTICE AND HEARING UNDER CHAPTER 903a OF THE CONNECTICUT GENERAL STATUTES, OR
AS OTHERWISE ALLOWED BY ANY STATE OR FEDERAL LAW WITH RESPECT TO ANY PREJUDGMENT
REMEDY WHICH LENDER MAY DESIRE TO USE, AND FURTHER, WAVES DILIGENCE, DEMAND,
PRESENTMENT FOR PAYMENT, NOTICE OF NONPAYMENT, PROTEST AND NOTICE OF PROTEST,
AND NOTICE OF ANY RENEWALS OR EXTENSIONS OF THIS NOTE, AND ALL RIGHTS UNDER ANY
STATUTE OF LIMITATION. THE BORROWER ACKNOWLEDGES THAT IT MAKES THIS WAIVER
KNOWINGLY, VOLUNTARILY, WITHOUT DURESS AND ONLY AFTER CONSIDERATION OF THE
RAMIFICATIONS OF THIS WAIVER WITH ITS ATTORNEYS.

     22. Jury Waiver. THE BORROWER HEREBY WAIVES TRIAL BY JURY IN ANY COURT AND
IN ANY SUIT, ACTION OR PROCEEDING ON ANY MATTER ARISING IN CONNECTION WITH OR IN
ANY WAY RELATED TO THE FINANCING TRANSACTIONS OF WHICH THIS NOTE IS A PART
AND/OR THE ENFORCEMENT OF ANY OF THE LENDER'S RIGHTS AND REMEDIES, INCLUDING
WITHOUT LIMITATION, TORT CLAIMS. THE BORROWER ACKNOWLEDGES THAT IT MAKES THIS
WAIVER KNOWINGLY, VOLUNTARILY, WITHOUT DURESS AND ONLY AFTER CONSIDERATION OF
THE RAMIFICATIONS OF THIS WAIVER WITH ITS ATTORNEYS.

     IN WITNESS WHEREOF, the Borrower has caused this Note to be duly executed
this 4th day of June, 1997.

                                                     ZYGO CORPORATION

                                                     By /s/ MARK J. BONNEY
                                                        -----------------------
                                                     Title: Vice President

                                       -8-