Exhibit 10.15

MKS INSTRUMENTS, INC.

SAR ASSUMPTION AGREEMENT

FOR EMPLOYEES OUTSIDE OF THE UNITED STATES

NEWPORT CORPORATION

AMENDED AND RESTATED 2011 STOCK INCENTIVE PLAN

2011 STOCK INCENTIVE PLAN

2006 PERFORMANCE-BASED STOCK INCENTIVE PLAN

Holder: [                                ]

STOCK APPRECIATION RIGHTS ASSUMPTION AGREEMENT effective as of April 29, 2016
(the “SAR Assumption Agreement”).

WHEREAS, MKS Instruments, Inc., a Massachusetts corporation (“MKS”), has
acquired Newport Corporation, a Nevada corporation (“Newport”), through the
merger of a wholly owned MKS subsidiary into Newport (the “Merger”) pursuant to
the Agreement and Plan of Merger, by and among MKS, Newport and such subsidiary
dated as of February 22, 2016, as may be amended from time to time (the “Merger
Agreement”).

WHEREAS, before the consummation of the Merger, you held one or more outstanding
awards of stock appreciation rights (“SARs”) with respect to shares of the
common stock of Newport that you received under the Newport Corporation Amended
and Restated 2011 Stock Incentive Plan, the Newport Corporation 2011 Stock
Incentive Plan, or the Newport Corporation 2006 Performance-Based Stock
Incentive Plan (each a “Newport Plan”), each of which is evidenced by a Stock
Appreciation Right Award Agreement (a “SAR Agreement”) issued to you under the
applicable Newport Plan.

WHEREAS, the provisions of the Merger Agreement require MKS to assume, upon the
effective time of the Merger (the “Effective Time”), each SAR award that was
outstanding as of immediately prior to the Effective Time by converting the
number of shares of Newport common stock, par value $0.1167 per share (“Newport
Common Stock”) covered by the SAR award into shares of MKS common stock, no par
value per share (“MKS Common Stock”), and adjusting the Base Value (as defined
in the applicable Newport Plan) of each SAR award, using an exchange ratio (the
“Equity Award Exchange Ratio”) determined based on the Merger consideration and
pre-closing trading prices for the MKS Common Stock under a method specified in
the Merger Agreement. MKS has provided you the actual Equity Award Exchange
Ratio in the employee communication to you regarding the conversion.

WHEREAS, the purpose of this SAR Assumption Agreement is to evidence MKS’s
assumption of your outstanding SAR award identified on Annex A hereto upon the
Effective Time and to reflect certain adjustments to that SAR award that are
necessary in connection with its assumption by MKS.

NOW, THEREFORE, MKS and you agree as follows:

1. MKS has assumed, as of the Effective Time, all the duties and obligations of
Newport under each of the SAR awards you held immediately prior to the Effective
Time (the “Newport SARs” and, as assumed, the “Assumed Newport SARs”) and will
issue from the MKS Instruments, Inc. 2014 Stock Incentive Plan as it may be
amended or replaced from time to time (the “MKS Incentive Plan”) any shares that
become distributable upon exercise of the Assumed Newport SAR awards. In
connection with such assumption, the number of shares of MKS Common Stock that
are subject to the Assumed Newport SAR award covered by this SAR Assumption
Agreement and the Base Value for each share of MKS Common Stock subject to such
Assumed Newport SAR award have been adjusted to reflect the Equity Award
Exchange Ratio, resulting in an Assumed Newport SAR award with respect to the
number of shares of MKS Common Stock and the Base Value for each share of MKS
Common Stock subject to such Assumed Newport SAR award indicated on Annex A
hereto.

2. By clicking acceptance to this SAR Assumption Agreement, you hereby
acknowledge receipt of this SAR Assumption Agreement and understand that all
rights and liabilities with respect to your Assumed Newport SAR award are as set
forth in the applicable SAR Agreement, the applicable Newport Plan (to the
extent incorporated into the SAR Agreement) and this SAR Assumption Agreement.

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3. The intent of the foregoing adjustments to each of your Newport SAR awards is
to preserve, immediately after the Effective Time, on a per-share basis, the
same ratio of the Base Value per share to the fair market value per share of the
Newport SAR award as determined based on the Merger consideration, except as
affected by rounding. For each Assumed Newport SAR award, the Base Value is
rounded up to the nearest cent, and the number of shares of MKS Common stock is
rounded down to the nearest whole share. Such adjustments also ensure that the
difference between the aggregate fair market value of the shares of MKS Common
Stock subject to each Assumed Newport SAR award and the aggregate Base Value
with respect to those shares (as adjusted pursuant to the Merger Agreement) will
not, immediately after the Effective Time, be greater than the difference that
existed, immediately prior to the Effective Time, between the then aggregate
fair market value of the shares of Newport Common Stock subject to the Newport
SAR and the aggregate Base Value with respect to those shares under each SAR
Agreement. You agree that this assumption satisfies Section 10.1 of the
applicable Newport Plan.

4. Each Assumed Newport SAR award will continue to have a maximum term of seven
years measured from the original grant date (as indicated on Annex A hereto),
subject to earlier termination (as provided in the applicable SAR Agreement)
following your ceasing to be in “Continuous Service” (as defined in the
applicable SAR Agreement and in paragraph 5(d) of this SAR Assumption
Agreement).

5. The following provisions will govern the Assumed Newport SAR award:

(a) Unless the context otherwise requires, all references in the applicable SAR
Agreement and the applicable Newport Plan (to the extent incorporated into such
SAR Agreement) are adjusted as follows: (i) all references to the “Company” mean
Newport (after the merger with a subsidiary of MKS) and any successor entity
into which Newport is subsequently merged and, for purposes of “Reorganization
Event” under the MKS Incentive Plan, MKS, (ii) all references to “Stock,”
“Common Stock” or “Shares” mean shares of MKS Common Stock, (iii) all references
to the “Board” mean the Board of Directors of MKS or the Compensation Committee
of such Board and (iv) any interpretation of corporate law for purposes of the
Assumed Newport SAR award will be under Massachusetts law rather than Nevada
law.

(b) The grant date and the expiration date of each Assumed Newport SAR award and
all other provisions governing either the exercise or the termination of each
Assumed Newport SAR award remain the same as set forth in the applicable SAR
Agreement, and those provisions (and any related provisions of the applicable
Newport Plan incorporated by reference into such SAR Agreement) will accordingly
govern and control your rights under this SAR Assumption Agreement to receive
MKS Common Stock under the Assumed Newport SAR award represented by this SAR
Assumption Agreement.

(c) No accelerated vesting of the Newport SARs has occurred by reason of the
Merger or MKS’s assumption of those SARs. Accordingly, the Assumed Newport SAR
award represented by this SAR Assumption Agreement will continue to vest in
accordance with the same installment vesting schedule in effect under that
Newport SAR award (as set forth in the applicable SAR Agreement) immediately
prior to the Effective Time except that the number of shares of MKS Common Stock
subject to each installment of such vesting schedule will be adjusted to reflect
the Equity Award Exchange Ratio. This statement is not intended to override any
post-Effective Time rights to acceleration you may have under any other
agreement with Newport.

(d) For purposes of applying any and all provisions of any SAR Agreement and the
applicable Newport Plan relating to your status as an employee or director of,
or consultant to, Newport or its parent or subsidiaries for purposes of
determining your Continuous Service, you will be deemed to be in Continuous
Service for as long as you continue to render services as an employee, director,
or a consultant to MKS or any present or future parent company or majority-owned
subsidiary of MKS. Accordingly, the provisions of each SAR Agreement governing
the termination of the Assumed Newport SAR awards in connection with your
ceasing to be an employee, director, or other service provider will, after the
Effective Time, be applied on the basis of your cessation of employee, director
or consultant status with MKS and its parent and majority-owned subsidiaries.

(e) To exercise each Assumed Newport SAR award, you must comply with the
instructions communicated to you with respect to electronic notice of exercise
on which you must indicate the number of shares of MKS Common Stock as to which
you are then exercising the Assumed Newport SAR award. You must also

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satisfy any tax withholding obligations in a manner provided under the SAR
Agreement, subject to such consents as are required from MKS. All notices must
be addressed to MKS’s stock plan administrator at the time of exercise (and,
currently, Fidelity Stock Plan Services).

(f) When SARs are exercised through MKS’s stock plan administrator’s automated
system, the net number of shares that you are entitled to receive upon such
exercise will be determined based upon a stock price on the date of exercise
determined in accordance with the procedures of MKS’s stock plan administrator,
which may differ from those used by Newport’s previous stock plan administrator
under the Newport Plan. You agree that, rather than using the closing price on
the date of exercise to determine (x) the number of shares of MKS Common Stock
that represent the value of the exercised SARs and (y), where applicable,
certain tax related obligations, MKS has directed the stock plan administrator
to use another method consistent with automated trading system functionality
that is common in the industry. This method currently involves processing SAR
exercises using the market price at the time of exercise (or, for exercises
executed after market hours, the opening price on the following trading day).
This functionality offered by Fidelity will allow you to sell the net shares
resulting from the exercise on the date of exercise (or on the next trading day
following the date of exercise if the exercise is executed after market hours).

(g) Taxes.

(i) MKS’s obligation to deliver Shares to you upon exercise of the SARs shall be
subject to the satisfaction of all income tax, social insurance, payroll tax,
payment on account, or other tax related requirements (“Tax Obligations”).

(ii) You have reviewed with your own tax advisors the Tax Obligations applicable
to you with respect to this Assumed Newport SAR award and the transactions
contemplated by this Agreement. You are relying solely on such advisors and not
on any statements or representations of MKS, Newport, or any of their affiliates
or agents. You understand that you (and not MKS, Newport or their affiliates)
shall be responsible for complying with your own Tax Obligations that may arise
as a result of this Assumed Newport SAR award or the transactions contemplated
by this Agreement.

(iii) MKS or its affiliates may be required to withhold amounts to satisfy Tax
Obligations on your behalf. To the extent that MKS or any of its affiliates pays
on your behalf any Tax Obligations for which you are responsible, MKS shall be
entitled to require a cash payment by or on behalf of you and/or to deduct from
other compensation payable to you the amount of any such Tax Obligations paid by
MKS or its affiliates.

6. Except to the extent specifically modified by this SAR Assumption Agreement,
all of the terms and conditions of the applicable SAR Agreement as in effect
immediately prior to the Effective Time continue in full force and effect and
are not in any way be amended, revised or otherwise affected by this SAR
Assumption Agreement.

IN WITNESS WHEREOF, MKS Instruments, Inc. has caused this SAR Assumption
Agreement to be delivered on its behalf by its duly-authorized officer or agent.

 

MKS INSTRUMENTS, INC. By:  

 

  Gerald G. Colella, CEO and President   Date: April 29, 2016

 

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Annex A

 

Name of SAR Holder    [                                         ] Original Grant
Date    [                                         ] Number of SARs After
Conversion    [                                         ] Base Value per Share
after Conversion    [                                         ]

(The number of shares covered by the SAR Award has been calculated by
multiplying the number of shares of Newport Common Stock represented by the SARs
by the Equity Award Exchange Ratio and rounding down to the nearest whole share.
The Base Value per Share has been calculated by dividing the Base Value per
Share of the SAR Award by the Equity Award Exchange Ratio and rounding up to the
nearest whole cent.)