Basic Plan Document # 05
                                                                      Plan # 002
                                                 IRS Letter Serial No.: D363689a

                     PRISM PROTOTYPE RETIREMENT PLAN & TRUST

                       Section 401(k) Profit Sharing Plan
                                (Nonstandardized)

                             Adoption Agreement <F1>


The Employer <F2>,  designated below,  hereby establishes a profit-sharing  plan
(optionally  including  a cash or  deferred  arrangement  (as defined in Section
401(k) of the Internal  Revenue Code)) for all Eligible  Employees as defined in
this Adoption Agreement pursuant to the terms of the PRISM Prototype  Retirement
Plan & Trust Basic Plan Document # 05.

A. Employer Information:

     1. Name:  Helix Technology Corporation

     2. Address:  Nine Hampshire Street

     3. Address:  Mansfield, MA  02048

     4. Attention:  Joseph Giorgio          Telephone:  508-337-5664

     5. Employer Taxpayer Identification Number <F3>:  04-2423640


B. Basic Plan Provisions:

     1. Plan Name (select one):

          a. ___ This plan is established effective , 19, (the "Effective Date")
as a  profit  sharing  plan  and  trust  (optionally  with a "cash  or  deferred
arrangement"  as defined in Code  Section  401(k)) to be known as Plan and Trust
(the "Plan") in the form of the PRISM Prototype Retirement Plan & Trust.

(PRISM is a registered trademark.)

<PAGE>

         b. X   This  plan  is an amendment and restatement in the form of the 
PRISM  Prototype  Retirement  Plan  &  Trust,  effective  April  1,  1998,  (the
"Effective Date") of the Helix Technology  Corporation Employee Savings Plan and
Trust (the "Plan"),  originally  effective as of January 1, 1979 (the  "Original
Effective Date").

     2. Employer's Three Digit Plan Number:  001

     3. Committee Members <F4>:  Michael El-Hillow, Chairman; Michael
        Eacobacci, Gregory Knox, Charles Chappell, and Joseph Giorgio, Members
  
     4. Definitions:

          a. Compensation for allocation purposes:

                  i  Will be determined  over the following  applicable  period
(select only one):

                     (a)          X the Plan Year
                     (b)         ___      the period of Plan  participation  
during the Plan Year
                     (c)         ___      a  consecutive  12 month period  
commencing on and ending with, or within, the Plan Year.

                  ii  X     If selected,  Compensation  will include Employer  
contributions  made  pursuant  to  a  Salary  Reduction   Agreement,   or  other
arrangement,  which are not includible in the gross income of the Employee under
Sections 125, 402(e)(3), 402(h)(1)(B) or 403(b) of the Internal Revenue Code.

                  iii         Shall not include (select as many as desired):

                     (a)      ___   Bonuses
                     (b)      ___   Commissions
                     (c)      ___   Taxable fringe benefits identified below:
 
                     (d)      ___   Other items of remuneration identified 
below:
 
 
                  iv Shall  be  limited  to  $ ,  which  shall  be  the  maximum
amount of  compensation  considered  for plan  allocation  purposes (but not for
testing  purposes),  and may not be an amount in excess of the Internal  Revenue
Code Section  401(a)(17) limit in effect for the Plan Year <F5>. If no amount is
<PAGE>

specified,  Compensation  shall  be limited to the Internal Revenue Code Section
401(a)(17)  amount,  as adjusted by the  Secretary of the Treasury  from time to
time.

            b.    Early Retirement Date:

                  i  ___      is not applicable to this Plan
                  ii  X       is the  latter  of the date on which the  
Participant  attains  age 55  (not  less  than  55) and the  date on  which  the
Participant completes 10 Years of Service.

            c.    Hour of Service shall be  determined  on the basis of the 
method  selected  below.  Only one method may be  selected.  The method shall be
applied to all Employees covered under the Plan as follows (select only one):

                  i   X       On the basis of actual  hours for which an  
Employee is paid, or entitled to be paid.
                  ii ___      On the basis of days  worked.  An  Employee  shall
be credited with ten (10) Hours of Service if under  Section  1.1(U) of the Plan
such Employee would be credited with at least one (1) Hour of Service during the
day.
                  iii         ___   On the  basis  of weeks  worked.  An  
Employee  shall be  credited  with  forty-five  (45)  Hours of  Service if under
Section 1.1(U) of the Plan such Employee would be credited with at least one (1)
Hour of Service during the week.
                  iv ___      On the basis of  semi-monthly  payroll  periods.
An Employee  shall be credited with  ninety-five  (95) Hours of Service if under
Section 1.1(U) of the Plan such Employee would be credited with at least one (1)
Hour of Service during the semi-monthly payroll period.
                  v  ___      On the basis of months  worked.  An Employee shall
be credited  with one  hundred  ninety  (190) Hours of Service if under  Section
1.1(U) of the Plan such Employee would be credited with at least one (1) Hour of
Service during the month.
 
            d.    Limitation  Year shall mean the 12 month period  commencing on
January 1 and ending on December 31.
<PAGE>

            e.    Normal Retirement Date for each Participant shall mean (select
one):

                  i   X       the date the Participant attains age:  65  (not to
exceed 65)
                  ii ___      the  latter of the date the  Participant  attains
age  (not  to  exceed  65)  or  the  (not  to  exceed  5th)  anniversary  of the
participation  commencement date. If for the Plan Years beginning before January
1, 1988, Normal Retirement Date was determined with reference to the anniversary
of the participation commencement date (more than 5 but not to exceed 10 years),
the anniversary date for Participants  who first commenced  participation  under
the Plan before the first Plan Year  beginning on or after January 1, 1988 shall
be the  earlier  of (A)  the  tenth  anniversary  of the  date  the  Participant
commenced  participation in the Plan (or such anniversary as had been elected by
the employer,  if less than 10) or (B) the fifth anniversary of the first day of
the first Plan Year beginning on or after January 1, 1988.  Notwithstanding  any
other provisions of the Plan, the participant commencement date is the first day
of the first Plan Year in which the Participant  commenced  participation in the
Plan.

            f.    Permitted   Disparity   Level,   for  purposes  of  allocating
Employer Contributions, shall mean (select only one):

                  i   X       Not applicable - the Plan does not use permitted
disparity.
                  ii ___      The Taxable Wage Base,  which is the  contribution
and benefit base under  section 230 of the Social  Security Act at the beginning
of the year.
                  iii         ___    % (not  greater  than 100%) of the Taxable
Wage Base as defined in B(4)(f)(ii) above.
                  iv ___      $ , provided  that the amount does not exceed the
Taxable Wage Base as defined in B(4)(f)(ii) above.

            g.    Plan Year shall mean (select and complete only one of the 
following):

                  i  ___      the  12-consecutive  month  period which coincides
with the Limitation Year. The first Plan Year shall be the period  commencing on
the Effective Date and ending on the last day of the Limitation Year.
                  ii ___      the  12-consecutive  month period  commencing on,
19, and each annual anniversary thereof.
                  iii          X    the calendar year (January 1 through 
December 31).

            h.    Qualified  Distribution Date, for purposes of making  
distributions  under the provisions of a Qualified  Domestic Relations Order (as
defined in Internal Revenue Code Section  414(p)),  X shall ___ shall not be the
date the  order is  determined  to be  qualified.  If  shall  is  selected,  the
<PAGE>

Alternate  Payee will be entitled to an  immediate  distribution  of benefits as
directed by the Qualified  Domestic  Relations  Order. If shall not is selected,
the Alternate  Payee may only take a distribution  on the earliest date that the
Participant is entitled to a distribution.

            i.    Spouse:

                     ___   If selected,  Spouse shall mean only that person who
has actually been the Participant's spouse for at least one year.

            j.    Year of Service shall mean:

                  i  For eligibility purposes (select one of the following):

                     (a)         ___      the  12   consecutive   months  during
which an Employee is credited with (not more than 1000) Hours of Service.
                     (b)          X a Period of Service  (using the  elapsed  
time method of counting Service, as described in Section 1.1(N)(3) of the Plan).

                  ii For allocation accrual purposes (select one of the
following):

                     (a)         ___      the  12   consecutive   months  during
which  an
                                 Employee  is  credited  with (not more than 
1000) Hours of Service.
                     (b)          X a Period of Service  (using the  elapsed  
time method of counting Service, as described in Section 1.1(N)(3) of the Plan).
                  iii   For vesting service purposes (select one of the  
following):

                     (a)         ___      the  12   consecutive   months  during
which an Employee is credited with (not more than 1000) Hours of Service.
                     (b)          X a Period of Service  (using the elapsed time
method of counting Service, as described in Section 1.1(N)(3) of the Plan).
                  iv For  purpose  of  computing  Years of  Service  in plans
where Year of Service is defined in terms of Hours of Service),  the consecutive
12 month period shall be:

                     (a)      For eligibility  purposes,  the first Year of
Service shall be computed using the 12 month period commencing on the Employee's
date of hire and ending on the first annual  anniversary of the Employee's  date
of hire (the "Initial  Computation  Period").  In the event an employee does not

<PAGE>

complete an eligibility Year of Service during this initial  computation period,
the computation period shall be (select only one):

                        (1)          X    the period  commencing on each annual
anniversary  of the  Employee's  date of hire  and  ending  on the  next  annual
anniversary of the Employee's date of hire.
                        (2)         ___   the Plan  Year,  commencing  with the
Plan Year in which the Initial Computation Period ends.

                     (b)      For vesting  purposes,  Years of Service  shall be
computed on the basis of:

                        (1)          X    the period  commencing on each annual 
anniversary  of the  Employee's  date of hire  and  ending  on the  next  annual
anniversary of the Employee's date of hire.
                        (2)         ___   the Plan  Year,  commencing  with the 
first Plan Year an Employee completes an Hour of Service.

                     (c)      For  allocation  accrual purposes, Year of Service
shall be computed on the basis of the Plan Year.

                  v  ___      For eligibility purposes,  Years of Service with
the following  Predecessor  Employers  shall count in fulfilling the eligibility
requirements for this Plan:
 
                  vi ___      For  vesting  purposes,  Years of Service  with
the following  Predecessor Employers shall count for purposes of determining the
nonforfeitable amount of a Participant's account:
 
 
      5.    Coverage:

            This Plan is extended by the Employer to the  following  Employees
who have met the eligibility requirements (select as many as appropriate):

                  i  ___      All Employees
                  ii ___      Salaried Employees
                  iii         ___   Sales Employees
                  iv ___      Hourly Employees
                  v  ___      Leased Employees
                  vi ___      All Employees except (select as applicable):

                              (a)       X those  who  are  members  of a unit
of Employees covered by a collective  bargaining  agreement between the Employer
and Employee  representatives,  if retirement  benefits were the subject of good
faith  bargaining  and if two percent or less of the  Employees  who are covered
pursuant to that agreement are professionals as defined in Section 1.410(b)-9 of
the Regulations.  For this purpose, the term "Employee  representative" does not
include any  organization  more than half of whose members are Employees who are
owners, officers, or executives of the Employer.
<PAGE>

                              (b)      ___      those  who are  nonresident  
aliens (within the meaning of Internal Revenue Code Section  7701(b)(1)(B))  and
who  receive no earned  income  (within the  meaning of  Internal  Revenue  Code
Section  911(d)(2))  from the  Employer  which  constitutes  income from sources
within the United  States  (within the meaning of Internal  Revenue Code Section
861(a)(3)).

                  vii         ___   Union  Employees  (who  are  members  of the
following unions or union affiliates:
 
                  viii  ___   Other Employees, described as follows:
 

      6.          Eligibility:

            An Employee  covered by the Plan may become a Participant upon 
completion of the following eligibility requirements:

            a.    Service <F6>:

                  i  ___      There shall be no minimum service  requirement for
an Employee to become a Participant.
                  ii  X       The Employee  must  complete 1 Year of Service 
(not  more  than  2  years)  to  be a  Participant  for  purposes  of  receiving
allocations of Employer Profit Sharing Contributions.

            b.    Age:

                  i   X       There shall be no minimum age  requirement  for an
Employee to become a Participant.
                  ii ___      The  Employee  must  attain  age  (not  more  than
21) to be a Participant in the Plan.
<PAGE>

            c.    Waiver of Age and Service Requirements:

                  i  ___      Notwithstanding  the  provisions of Items  B(6)(a)
and (b), Employees who have not satisfied the age and service requirements,  but
would  otherwise be eligible to  participate  in the plan,  shall be eligible to
participate on the Effective Date.

                  ii ___      For  new  Plans,  notwithstanding  the  provisions
of Items  B(6)(a) and (b),  Employees who have not satisfied the age and service
requirements,  but would otherwise be eligible to participate in the plan, shall
be eligible to participate on the Effective Date.

            d.    Entry Dates:

                  Upon  completion  of  the  eligibility  requirements,  an 
Employee shall commence participation in the Plan (select only one):

                  i    X      As soon as practicable under the payroll practices
utilized by the  Employer,  and  consistently  applied to all  Employees,  or if
earlier, the first day of the Plan Year <F7>.
                  ii ___      As of the first day of the month  following the  
completion of the eligibility requirements.
                  iii         ___   As of the  earliest  of the first day of the
Plan  Year,  fourth,  seventh  or tenth  month of the Plan Year  next  following
completion of the eligibility requirements.
                  iv ___      As of the  earliest  of the  first day of the Plan
Year or  seventh  month  of the  Plan  Year  next  following  completion  of the
eligibility requirements.
                  v  ___      As  of  the  first  day  of  the  Plan  Year  next
following  completion of the eligibility  requirements  (may only be selected if
the eligibility year of service requirement is 6 months or less).

      7.    Vesting:

            a.    The  percentage  of  a   Participant's   Employer Contribution
Account (attributable to Employer Profit Sharing  Contributions) to be vested in


<PAGE>

him or her upon  termination  of  employment  prior to  attainment of the Plan's
Normal Retirement Date shall be <F8>:

                              Completed Years of Service

                                 1     2      3     4     5     6     7

                  i     ___           100%
                  ii    ___                  100%
                  iii   ___            20%    40%   60%   80%  100%
                  iv    ___                   20%   40%   60%   80%   100%
                  v     ___      10%   20%    30%   40%   60%   80%   100%
                  vi     X        0%   50%    75%  100%  100%
                  vii   ___                                           100%
                  vii   ___Full and immediate vesting upon entry into the 
Plan <F9>

Notwithstanding anything to the contrary in the Plan, the amount inserted in the
blanks above shall not exceed the limits specified in Code Section 411(a)(2).

            b.    For purposes of computing a Participant's  vested account  
balance,  Years of Service  for  vesting  purposes X shall ___ shall not include
Years of Service  before the Employer  maintained  this Plan or any  predecessor
plan,  and X shall ___ shall not include  Years of Service  before the  Employee
attained age 18.
            c.    Notwithstanding  the  provisions  of this  Item  B(7)(c)  of 
the  Adoption  Agreement,  a  Participant  shall  become  fully  vested  in  his
Participant's Employer Contribution if: <F10>

                  i  ___      the  Participant's  job is eliminated  without the
Participant being offered a comparable position elsewhere with the Employer.
                  ii ___      for such reason as is described below:
 

      8.    Employer Profit Sharing Contributions:

            a.    Contributions:

                  i   X       In  its  discretion,  the  Employer may contribute
Employer Profit Sharing Contributions to the Plan.

<PAGE>

                  ii ___      The  Employer  shall   contribute  Employer Profit
Sharing  Contributions to the Plan in the amount of % of the Compensation of all
Eligible Participants under the Plan.
                  iii          X    If  selected,  the  Employer  may make  
Employer Profit Sharing  Contributions  without regard to current or accumulated
Net Profits of the Employer for the taxable year ending with, or within the Plan
Year.
                  iv  X       If selected,  the Employer  may  designate  all or
any part of the Employer Profit Sharing  Contributions as Qualified  Nonelective
Contributions,  provided,  however,  that  contributions  so designated  will be
subject to the same vesting, distribution, and withdrawal restrictions as Before
Tax Contributions <F11>.

            b.    Allocations:

                  Employer Profit Sharing  Contributions  shall be allocated to
the  accounts of  eligible  Participants  according  to the  following  selected
allocation formula:
                  i   X       The Employer Profit Sharing  Contributions  shall
be  allocated  to each  eligible  Participant's  account in the ratio  which the
Participant's   Compensation   bears  to  the   Compensation   of  all  eligible
Participants.  Employer Profit Sharing Plan Contributions, shall be allocated to
the accounts of Participants  who have completed a Year of Service <F12> (select
one):

                              (a)         ___   as of the  last day of the month
preceding the month in which the contribution was made.
                              (b)         ___   as of  the  last day of the Plan
quarter preceding the quarter in which the contribution was made.
                              (c)          X    as of the last day of the Plan
Year.

                  ii ___      The Employer Profit Sharing  Contributions  shall
be allocated in accordance with the following formula:

                              (a)   If the  Plan is Top-Heavy, the  contribution
shall be first  credited  to each  eligible  Participant's  Account in the ratio
which the  Participant's  Compensation  bears to the total  Compensation  of all
eligible Participants, up to 3% of each Participant's Compensation.

<PAGE>

                              (b)   If the Plan is Top-Heavy,  any Employer  
Profit Sharing Contribution remaining after the allocation in (a) above shall be
credited  to  each  eligible  Participant's  account  in  the  ratio  which  the
Participant's  Excess  Compensation <F13> bears to the total Excess Compensation
of all eligible  Participants,  up to 3% of each eligible  Participant's  Excess
Compensation.
                              (c)   Any contributions  remaining after the 
allocation in (b) above shall be credited to each eligible Participant's account
in the ratio which the sum of the  Participant's  total  Compensation and Excess
Compensation bears to the sum of the total Compensation and Excess  Compensation
of all  eligible  Participants,  up to an  amount  equal to the  maximum  Excess
Percentage  times  the  sum  of  the   Participant's   Compensation  and  Excess
Compensation.  If the Plan is Top-Heavy,  the maximum Excess  Percentage is N/A%
(insert percentage). If the Plan is not Top-Heavy, the maximum Excess Percentage
is N/A% (insert  percentage,  which shall not exceed the prior Excess Percentage
limitation specified by more than 3).

                         Note:   If the  Permitted  Disparity  Level defined at
Item  B(4)(f) is the Taxable  Wage Base (which is the  contribution  and benefit
base under section 230 of the Social Security Act at the beginning of the year),
then the maximum Excess  Percentage  should be 2.7% if the Plan is Top-Heavy and
5.7% if the Plan is not Top-Heavy.

                                 If the  Permitted  Disparity  Level defined at
Item  B(4)(f) is greater  than 80% but less than 100% of the Taxable  Wage Base,
then the maximum Excess  Percentage  should be 2.4% if the Plan is Top-Heavy and
5.4% if the Plan is not Top-Heavy.

                                 If the  Permitted  Disparity  Level defined at
Item  B(4)(f) is greater  than the greater of $10,000 or 20% of the Taxable Wage
Base, but not more than 80%, then the maximum Excess  Percentage  should be 1.3%
if the Plan is Top-Heavy and 4.3% if the Plan is not Top-Heavy.


<PAGE>

                              (d)   Any  remaining  Employer  Profit  Sharing
Contribution  shall be allocated  among eligible  Participants'  accounts in the
ratio which the Participant's  Compensation  bears to the total  Compensation of
all Participants.
                  iii         ___   If  selected,  and the  Employer has elected
to allocate Employer Profit Sharing Plan Contributions as of the last day of the
Plan Year, a Participant must be employed by the Employer on the last day of the
Plan Year in order to receive an allocation <F14>.
                  iv ___      A Participant who terminates  before the end of 
the period for which  contributions  are allocated shall share in the allocation
of Employer  Profit Sharing  Contributions  if termination of employment was the
result of (select all that apply):

                              (a)         ___   retirement
                              (b)         ___   disability
                              (c)         ___   death
                              (d)         ___   other, as specified below:
 
 
      9.    Rollover & Transfer Contributions (select one):

            a. ___      Subject to policies,  applied in a consistent and
nondiscriminatory  manner,  adopted by the Committee,  each Employee,  who would
otherwise be eligible to  participate  in the Plan except that such Employee has
not yet met the  eligibility  requirements,  and  each  Participant  may  make a
Rollover Contribution as described in Internal Revenue Code  Sections 402(a)(5),
403(a)(4) or 408(d)(3).
            b.  X       Subject to policies,  applied in a consistent and
nondiscriminatory  manner, adopted by the Committee, each Participant may make a
Rollover Contribution  as described in Internal Revenue Code Sections 402(a)(5),
403(a)(4) or 408(d)(3).
            c. ___      No Employee shall make Rollover Contributions to the
Plan.

      10.   Distributions:

            a.    Distributions Upon Separation from Service:

                  The  Normal  Form of  Benefit  under the Plan  shall be a
single lump sum distribution,  made X (if selected) as soon as  administratively
practical after receipt of a distribution request from a Participant entitled to
a  distribution  or ___ (if selected) upon the  Participant's  attainment of the
Plan's Early Retirement Date or the Plan's Normal Retirement Date,  whichever is
earlier. See Attached Addendum
<PAGE>

                  In  addition  to the Normal  Form of  Benefit,  the  
Participant shall be entitled to select from among the following  optional forms
of benefit specified by the employer (select as many as apply):

                  i   X       Installment payments
                  ii ___      Such other forms as may be specified below:
 

            b.          In-Service Distributions (select as may be appropriate):

                  i   X       There  shall  be no  in-service  distribution  of
Participant account balances derived from Employer Profit Sharing Contributions.
                  ii ___      Participants  may request an in-service  
distribution  of their account  balance  attributable to Employer Profit Sharing
Contributions, for the following reasons:

                              (a)         ___   For  purposes  of   satisfying
a  financial   hardship,   as  determined   in   accordance   with  the  uniform
nondiscriminatory policy of the Committee;
                              (b)         ___   Attainment of age 59 1/2 by the
Participant; or
                              (c)         ___   Attainment of the Plan's  Normal
Retirement Date by the Participant.
      11.         Forfeitures:

            a.    Forfeitures   of  amounts   attributable   to  Employer Profit
Sharing Contributions shall be reallocated as of:

                  i   X       the  last  day  of the  Plan  Year  in  which  the
Forfeiture occurred.
                  ii ___      the last  day of the  Plan  Year  following  the
Plan Year in which the Forfeiture occurred.
                  iii         ___   the last day of the Plan Year in which  the
Participant  suffering the  Forfeiture  has incurred five  consecutive  One Year
Breaks in Service.

            b.    Forfeitures of Employer Profit Sharing  Contributions shall be
reallocated as follows:

                  i  ___      Not applicable as Employer  Profit Sharing  
Contributions are always 100% vested and nonforfeitable.

<PAGE>

                  ii ___      Used first to pay the expenses of administering  
the Plan, and then allocated pursuant to one of the following two options <F15>:
                  iii         ___   Forfeitures   shall  be   allocated   to   
Participant's   accounts  in  the  same  manner  as  Employer   Profit   Sharing
Contributions,   Employer   Matching   Contributions,    Qualified   Nonelective
Contributions  or Qualified  Matching  Contributions,  in the  discretion of the
Employer, for the year in which the Forfeiture arose.
                  iv  X       Forfeitures  shall be applied to reduce  the  
Employer  Profit  Sharing   Contributions,   Employer  Matching   Contributions,
Qualified Nonelective Contributions or Qualified Matching Contributions,  in the
discretion of the Employer,  for the Plan Year  following the Plan Year in which
the Forfeiture arose.

      12.   Limitations on Allocations:

            If the Employer maintains or ever maintained  another qualified  
retirement plan in which any Participant in this Plan is (or was) a participant,
or  could  possibly  become  a  participant,  the  Employer  must  complete  the
following:

            a.    If  the   Participant   is  covered   under  another   
qualified  defined  contribution  plan  maintained by the Employer  other than a
Master or Prototype Plan:

                  i  ___      The  provisions  of this Plan shall apply as if 
the other plan were a Master or Prototype plan; or,
                  ii ___      The following  provisions will be effective to
limit the total Annual  Additions to the Maximum  Permissible  Amount,  and will
properly  reduce  any  Excess  Amounts,  in a  manner  that  precludes  Employer
discretion:
 

                  b.          If the  Participant  is or ever  has been a  
participant in a qualified defined benefit plan maintained by the Employer,  the
following provisions will be effective to satisfy the 1.0 limitation of Internal
Revenue Code Section  415(e),  in a manner that precludes  Employer  discretion:
Contributions to this plan will be reduced first, in the following order: First,
Participant   Before  Tax   Contributions;   Second,   any  Qualified   Matching
Contributions;  Third,  any qualified  nonelective  contributions;  Fourth,  any
Employer Matching Contributions;  and Finally, any Profit Sharing Contributions.
Contributions  will only be  reduced  to the extent  necessary  to  satisfy  the
requirements of Section 415(e) of the Code, and to the extent  allowable,amounts
which may be distributed to the Participant to satisfy those  requirements  will
be refunded.

<PAGE>

      13.   Internal Revenue Code 411(d)(6) Protected Benefits:

             X    If  selected,  the Plan has  Internal  Revenue  Code Section
411(d)(6)  Protected Benefits from a prior plan that this Plan amends, that must
be protected. (Attached addendum)

      14.   Top-Heavy Plan Provisions:

            For  each  Plan  Year in  which  the  Plan is a  Top-Heavy  Plan
the following provisions will apply:

            a.    The  percentage of a  Participant's  Employer  Contribution  
Account to be vested in him upon  termination of employment  prior to retirement
shall be:

                  i  ___      a  percentage  determined  in  accordance  with 
the following schedule:

                              Years of Service        Percentage

                              Less than two               0
                              Two but less than three    20
                              Three but less than four   40
                              Four but less than five    60
                              Five but less than six     80
                              Six or more               100;

                  ii ___      100%  vesting  after  (not to  exceed  3)  Years
of Service;  provided,  however, that Years of Service may not exceed two (2) if
the service requirement for eligibility exceeds 1 year; or
                  iii          X    computed  in  accordance   with  the vesting
schedule  selected by the Employer in Items  B(7)(a) or C(4)(d),  as long as the
benefits under the vesting schedule in Items B(7)(a) or C(4)(d) vest at least as
rapidly as the two options specified in this Item B(14)(a), above.

                  If the vesting  schedule  under the Plan shifts in or out of
the schedules  above for any Plan Year because of the Plan's  Top-Heavy  status,
such shift is an  amendment  to the vesting  schedule and the election in 2.2 of
the Basic Plan Document applies.

            b.    For  purposes  of  minimum   Top-Heavy   allocations,   
contributions  and  forfeitures  equal to 3% (not less than 3%) of each  Non-key
Employee's  Compensation  will be allocated to each  Participant's  Contribution
Account when the Plan is a Top-Heavy Plan,  except as otherwise  provided in the
Basic  Plan  Document.  This  Item 14 will not apply to any  Participant  to the
extent the  Participant is covered under any other plan or plans of the Employer
and the Employer completes the following:  (Insert the name of the plan or plans
which will meet the minimum  allocation  or benefit  requirement  applicable  to
Top-Heavy plans.)  Helix Technology Corporation Employees' Pension Plan
<PAGE>
 
            c.    The  Valuation  Date as of which  account  balances or accrued
benefits are valued for purposes of computing the  Top-Heavy  Ratio shall be the
last day of each Plan Year.

            d.    If the  Employer  maintains  or has ever  maintained  one or
more defined  benefit plans which have covered or could cover a  Participant  in
this Plan, complete the following:

                  Present Value:  For purposes of establishing  Present Value to
compute the Top-Heavy  Ratio, any benefit shall be discounted only for mortality
and interest based on the following:

                  Interest rate  %              Mortality table

      15.   Investments:

            a.    Investments  made pursuant to the investment  direction  
provisions  of the  Basic  Plan  Document  shall be made  into  any  appropriate
Investment  Fund as selected by the  Employer.  In addition,  investment of Plan
assets is expressly authorized, as required by Revenue Ruling 81-100, in each of
the  following  common or  collective  funds  sponsored  by the  Trustee,  or an
affiliate of the Trustee <F16>:
                  Key Trust EB Managed  Guaranteed  Income Contract Fund, Key 
Trust  Multiple   Investment  Trust  for  Employee  Benefit  Trusts,  and  other
collective  trusts  exempt from tax under IRC 501 and as described in Rev.  Rul.
81-100.

            b. X        If  selected,  an  Employer  Stock  Fund  shall be  
available  as an  Investment  Fund  pursuant  to the  terms  of the  Basic  Plan
Document.
                        ___   If  selected,  and an Employer  Stock Fund is  
available   as  an   Investment   Fund,   Participants   will  have  the  right,
notwithstanding  any other  provisions  of the Plan, to direct that a portion of
the Plan assets held for their  benefit and invested in the Employer  Stock Fund
be diversified  pursuant to the provisions of Section  10.7(F) of the Basic Plan
Document.

<PAGE>

            c.    Participants  may make  changes of existing  account  balances
and future contributions from among the Investment Funds offered:

                  i  ___      Once  during  each  business  day that the Trustee
and the New York Stock Exchange are open.
                  ii ___      Once during each calendar month.
                  iii          X    Once during each quarter of the Plan Year.
                  iv ___      Once during each rolling ____ day period.
 
            d.       X        If selected,  the Participant  shall be restricted
in making  changes of existing  account  balances from any  Investment  Fund, as
specified in the terms or conditions of such  Investment  Fund, and the Employer
shall attach an addendum specifying such restriction.

            e.    The   Participant   will  designate  into  which   Investment
Funds all contributions to their accounts are made, except the following:

                  i  ___      Employer Profit Sharing Contributions
                  ii ___      Employer Mandatory Matching Contributions
                  i    X      Employer Discretionary Matching Contributions
                  iv ___      Qualified Matching Contributions
                  v  ___      Qualified Nonelective Contributions

            f.  X       If  selected,  and to the  extent a  selection  is made
above, the Employer shall attach an Investment Direction Addendum specifying how
the contributions so specified shall be invested among the Investment Fund.

            g.  X       If selected,  the Participant  shall be restricted in 
the use of the Employer  Stock Fund as an Investment  Fund for  designating  the
investment of contributions in the Participant's account, as follows:

                        i   X       The  Participant  may not direct the  
investment of Plan assets held in their account into the Employer Stock Fund.
                        ii ___      The   Participant   may   direct  %  of  the
following contributions into the Employer Stock Fund:

                                    (a) ___   Employer Profit Sharing 
                                              Contributions
                                    (b) ___   Employer Mandatory Matching
                                              Contributions
                                    (c) ___   Employer Discretionary Matching
                                              Contributions
                                    (d) ___   Qualified Matching Contributions
                                    (e) ___   Qualified Nonelective 
                                              Contributions



<PAGE>



                        iii ___     ____  % of the  following  contributions
will be invested into the Employer Stock Fund, with the balance invested among:

                                    (a) ___   the other Investment Funds,  
                                              including the Employer Stock Fund
                                    (b) ___   the  other Investment Funds,   not
                                              including the Employer Stock Fund
      16.   Loans (select one):

            a.  X       Loans may be made from the Plan in  accordance  with the
Basic Plan Document and such policies and  procedures as the Committee may adopt
and apply on a consistent and nondiscriminatory basis <F17>.
            b. ___      No loans shall be made from the Plan.

      17.   Trustee:

     The Trustee of this Plan shall be Key Trust  Company of Ohio,  N.A. (a bank
or trust company  affiliated with KeyCorp within the meaning of Internal Revenue
Code 1504).

      18.         Effective Date Addendum:

            ___      If  selected,   the  following  provisions  shall  have
the specified  effective  dates (which are different  from the date specified in
Item B(1)):
 
<PAGE>


C.    Section 401(k) Plan Provisions:


      1.    Service:

            An Eligible  Employee  shall be required  to fulfill the  following
eligibility  service  requirements in order to participate in the Plan through a
salary  reduction  agreement  and for  purposes of receiving  an  allocation  of
Employer Matching Contributions:

            a.  X       The  Employee  must  complete  1 Year of Service
(not more than 1 year) to be a Participant for purposes of receiving allocations
of Employer Matching Contributions.
            b.  X       The  Employee  must  complete 1 Year of Service
(not more than 1 year) to be a  Participant  for  purposes  of  entering  into a
Salary  Reduction  Agreement and having  Employee  Before Tax  Contributions  or
Employee  After  Tax  Contributions  contributed  to the Plan on the  Employee's
behalf.

      2.    Employee Salary Deferrals:

            a.  X       Participants  shall be entitled  to enter  into a Salary
Reduction  Agreement  providing for Before Tax  Contributions  to be made to the
Plan.

                        i  The  minimum   Before  Tax   Contribution   shall  be
1% of the Participant's Compensation.
                        ii The  maximum   Before  Tax   Contribution   shall  be
15% of the Participant's Compensation.

            b.  X       Participants  shall be entitled  to enter  into a Salary
Reduction  Agreement  providing  for After Tax  Contributions  to be made to the
Plan.

                        i  The   minimum   After  Tax   Contribution   shall  be
1% of the Participant's Compensation.
                        ii The   maximum   After  Tax   Contribution   shall  be
15% of the Participant's Compensation.
                        iii         ___   If   selected,   notwithstanding   the
above,  a  Participant  shall  not be  able to  enter  into a  Salary  Reduction
Agreement  providing for After Tax  Contributions  to be made to the Plan unless
the Participant has entered into a Salary Reduction  Agreement that provides for
Before  Tax  Contributions  to be made to the Plan in an amount of at least % of
the Participant's Compensation.

<PAGE>

            c.  X       If selected,  a Participant shall be entitled to enter
into a Salary  Reduction  Agreement  providing  that any  extraordinary  item of
compensation,  not  yet  payable  (including  bonuses),  be  withheld  from  the
Participant's  Compensation  and  contributed to the Plan as either a Before Tax
Contribution,  or  After  Tax  Contribution  (provided  such  contributions  are
authorized above, and to the extent that such contribution, when aggregated with
either  the   Participants   other  Before  Tax   Contributions   or  After  Tax
Contributions  do not  exceed  the  limitations  specified  above,  on an annual
basis).

      3.          Contribution Changes:

            a.    Participants may increase or decrease the amount of 
contributions  made to the Plan pursuant to a Salary  Reduction  Agreement  once
each:
                  i        ___      Plan Year
                  ii       ___      Semi-annual period, based on the Plan Year
                  iii       X       Quarter, based on the Plan Year
                  iv       ___      Month
                  v        ___   Other,  as specified  below  (provided  that it
is   at least once per year):
 

               b. Claims  for   returns  of  Excess   Before  Tax  Contributions
for the  Participant's  preceding  taxable  year  must be made in  writing,  and
submitted to the Committee by April 15 (specify a date between March 1 and April
15).
<F18>
      4.          Employer Matching Contributions <F19>:

            a.    Mandatory Matching Contributions:

                  The Employer shall make contributions to the Plan, in an 
amount as specified below:

                  i   X       An  amount, equal to 50% of  each  Participant's
Before  Tax  Contributions,  however,  no match  shall be made on  Participant's
Before  Tax  Contributions  in  excess  of  3% (or  $  )  of  the  Participant's
Compensation.
                  ii ___      An  amount,  equal  to  %  of  each  Participant's
After Tax Contributions,  but not to exceed % of the Participant's Compensation,
or $ .


<PAGE>

                  iii         ___   An   amount,   equal   to   %  of   each   
Participant's  contributions  made  pursuant  to a  Salary  Reduction  Agreement
(including both Before Tax Contributions and After Tax Contributions),  but only
if the Participant has entered into a Salary Reduction  Agreement  providing for
Before Tax  Contributions of at least % of the Participant's  Compensation,  but
not to exceed % of the Participant's Compensation, or $ .
                  iv ___      An amount equal to the sum of the following:

                              (a)         %   of   the   first   %  of   the
Participant's  Compensation  deferred pursuant to a Salary Reduction  Agreement;
plus,
                              (b)         %   of   the   next   %   of   the   
Participant's  Compensation  deferred pursuant to a Salary Reduction  Agreement;
plus,
                              (c)         %   of   the   next   %   of   the   
Participant's  Compensation  deferred pursuant to a Salary Reduction  Agreement,
but not to exceed % of the Participant's Compensation, or $ .
                  v  ___      An amount  equal to $ , for each  Participant  who
enters  into  a  Salary  Reduction   Agreement  providing  for  ___  Before  Tax
Contributions,   ___  After  Tax   Contributions,   or  ___  either  Before  Tax
Contributions or After Tax  Contributions (or a combination of both) equal to or
exceeding % of the Participant's Compensation.  Such contributions shall be made
and allocated:

                              (a)         ___   only  during the first Plan Year
the Plan is in effect,  or if a  restatement,  for the first Plan Year beginning
with, or containing the restatement Effective Date.
                              (b)         ___   each  Plan Year  that a 
Participant  has in force a Salary  Reduction  Agreement  meeting  the  criteria
specified above.
                              (c)         ___   during   the   first   Plan Year
that the Participant  participates  through a Salary Reduction Agreement meeting
the criteria specified above.

            b.          Discretionary Matching Contributions:

                   X    The  Employer  shall  make  contributions  to the  Plan,
in an amount  determined  by  resolution  of the Board of Directors on an annual
basis. The Board  resolution  shall provide for the percentage  and/or amount of
Before Tax  Contributions  and/or After Tax  Contributions to be matched and the
maximum  percentage and/or amount of Before Tax  Contributions  and/or After Tax
Contributions eligible for matching.

<PAGE>

            c.          Allocation of Matching Contributions:

                  Employer Matching  Contributions  shall be allocated pursuant
to the terms of the Basic Plan Document, notwithstanding the foregoing:

                  i  ___      A Participant who terminates  before the end of
the period for which  contributions  are allocated shall share in the allocation
of Employer  Matching  Contributions if termination of employment was the result
of (select all that apply):
                              (a)         ___   retirement
                              (b)         ___   disability
                              (c)         ___   death
                              (d)         ___   other, as specified below:
 

                  ii  X       Employer  Matching  Contributions  shall be 
allocated to the accounts of Participants (select one):

                              (a)          X    as  of  each   pay   period  for
which a contribution was made pursuant to a Salary Reduction Agreement.
                              (b)         ___   semi-monthly.
                              (c)         ___   as of the  last day of the month
preceding the month in which the contribution was made.
                              (d)         ___   as of  the  last  day of  the 
Plan quarter preceding the quarter in which the contribution was made.
                              (e)         ___   as of the last day of the Plan
year.
<PAGE>


                  iii          X    If selected, the Employer  may make Employer
Matching  Contributions  without regard to current or accumulated Net Profits of
the Employer for the taxable year ending with, or within the Plan Year <F20>.

            d.    The percentage of a Participant's  Employer Matching 
Contribution Account <F21> (attributable to Employer Matching  Contributions) to
be vested in him or her upon  termination  of employment  prior to attainment of
the Plan's Normal Retirement Date shall be <F22>:

                              Completed Years of Service

                                  1    2      3      4    5     6      7


                  i     ___           100%
                  ii    ___                   100%
                  iii   ___            20%     40%   60%   80%   100%
                  iv    ___                   20%    40%   60%   80%   100%
                  v     ___      10%   20%    30%    40%   60%   80%   100%
                  vi     X        0%   50%    75%   100%  100%
                  vii   ___                                            100%
                  vii   ___  Full and immediate vesting upon entry into the Plan

                        Notwithstanding  anything to the  contrary  in the Plan,
the amount inserted in the blanks above shall not exceed the limits specified in
Code 411(a)(2).
            e.    Notwithstanding  the  provisions  of this  Item  C(4)(e)  of
the  Adoption  Agreement,  a  Participant  shall  become  fully  vested  in  his
Participant's Employer Matching Contribution Account if <F23>:
                  i  ___      the  Participant's  job is eliminated  without the
Participant being offered a comparable position elsewhere with the Employer.
                  ii ___      for such reason as is described below:
 

            f.          Corrective Contributions:

                  i   X       If  selected,   the  Employer  shall  be  
authorized to make Qualified Matching Contributions, subject to the terms of the
Basic Plan  Document,  in an amount  determined  by  resolution  of the Board of
Directors on an annual basis.
<PAGE>

                  ii  X       If  selected,   the  Employer  shall be authorized
to make Qualified Nonelective  Contributions,  subject to the terms of the Basic
Plan Document,  in an amount  determined by resolution of the Board of Directors
on an annual basis.

      5.          Gap Earnings:

            ___      If selected,  Gap  Earnings,  as defined in Section 3.2(G)
(1) of  the  Basic  Plan  Document,  will  be  calculated  for  Excess  Elective
Deferrals, Excess Contributions and Excess Aggregate Contributions, and refunded
to the Participant as provided for in Article III of the Basic Plan Document.

      6.          Forfeitures:

            a. Forfeitures of amounts attributable to Employer Matching 
Contributions shall be reallocated as of:

                  i   X       the  last  day  of the  Plan  Year  in  which  the
Forfeiture occurred.
                  ii ___      the last  day of the  Plan  Year  following  the
Plan Year in which the Forfeiture occurred.
                  iii___      the last day of the Plan Year in which  the
Participant suffering the Forfeiture has incurred the fifth consecutive One Year
Break in Service.

            b.    Forfeitures  of Employer  Matching  Contributions  shall be
reallocated as follows:
                  i  ___      Not applicable as Employer  Matching Contributions
are always 100% vested and nonforfeitable.
                  ii ___      Used first to pay the expenses of administering  
the Plan, and then allocated pursuant to one of the following two options:
                  iii         ___   Forfeitures   shall  be   allocated   to   
Participant's   accounts  in  the  same  manner  as  Employer   Profit   Sharing
Contributions,   Employer   Matching   Contributions,    Qualified   Nonelective
Contributions  or Qualified  Matching  Contributions,  in the  discretion of the
Employer, for the year in which the Forfeiture arose.
                  iv  X       Forfeitures  shall be applied to reduce  the  
Employer  Profit  Sharing   Contributions,   Employer  Matching   Contributions,
Qualified Nonelective Contributions or Qualified Matching Contributions,  in the
discretion of the Employer,  for the Plan Year  following the Plan Year in which
the Forfeiture arose.
<PAGE>

            c.    Forfeitures of Excess Aggregate Contributions shall be:

                  i  ___      Applied to reduce Employer  contributions for the
Plan Year in which the excess arose,  but allocated as below,  to the extent the
excess  exceeds  Employer  contributions  for the Plan Year, or the Employer has
already contributed for such Plan Year.
                  ii  X       Allocated after all other forfeitures under the 
Plan:

                              (a)         ___   to  the  Matching  Contribution
account  of  each  Non-highly  Compensated   Participant  who  made  Before  Tax
Contributions  or  After  Tax   Contributions  in  the  ratio  which  each  such
Participant's  Compensation for the Plan Year bears to the total Compensation of
all such Participants for the Plan Year; or,
                              (b)          X    to  the  Matching  Contribution
account of each Non-highly  Compensated  Eligible Participant in the ratio which
each Eligible  Participant's  Compensation  for the Plan Year bears to the total
Compensation of all Eligible Participants for the Plan Year.
      7.          In-Service Distributions (select as may be appropriate):

            a.   ___    There shall be no in-service  distribution  of  
Participant  account balances derived from Before Tax  Contributions  (including
Qualified Nonelective Contributions and Qualified Matching Contributions treated
as Before  Tax  Contributions  under the terms of the Basic Plan  Document),  or
Employer Matching Contributions.

            b.    X     Participants  may  request  an  in-service  distribution
of their account balance  attributable to Employer Matching  Contributions,  for
the following reasons: See Attached Addendum
                        i     X     For  purposes of  satisfying  a financial
hardship, as determined in accordance with the uniform  nondiscriminatory policy
of the Committee;
                        ii   ___    Attainment of age 59 1/2 by the
Participant; or
                        iii  ___    Attainment of the Plan's Normal  Retirement
Date by the Participant.

            c.    X     Participants  may  request  an  in-service  distribution
of their account balance attributable to Employee Before Tax Contributions,  for
the following reasons:

<PAGE>

                        i    ___    For  purposes of  satisfying  a financial
hardship,  as  determined  by  the  facts  and  circumstances  of an  Employee's
situation,  in accordance  with the  provisions of Section 3.9 of the Basic Plan
Document;
                        ii    X     For purposes of satisfying a financial  
hardship,  using the "safe  harbor"  provisions of Section 3.9 of the Basic Plan
Document.
                        iii   X     Attainment of age 59 1/2 by the Participant;
or
                        iv   ___    Attainment of the Plan's Normal  Retirement
Date by the Participant.

<PAGE>

NOTICE:  The adopting  Employer may not rely on an opinion  letter issued by the
National  Office of the Internal  Revenue  Service as evidence  that the Plan is
qualified  under the provisions of Section 401 of the Internal  Revenue Code. In
order to obtain reliance with respect to the Plan's qualification,  the Employer
must apply to the Key  District  Office of the  Internal  Revenue  Service for a
determination letter.

This Adoption Agreement may only be used in conjunction with Basic Plan Document
# 05.

This Plan document may only be used under the express authority of KeyCorp,  its
subsidiaries and affiliates, and is not effective as completed until executed by
a duly authorized officer of KeyCorp, one of its subsidiaries or affiliates, and
approved by KeyCorp's counsel.

KeyCorp, as sponsor,  may amend or discontinue this prototype plan document upon
proper notification to all adopting Employers pursuant to Revenue Ruling 89-13.

Failure   to   properly   fill  out  an   Adoption   Agreement   may  result  in
disqualification  of the Plan, and adverse tax  consequences to the Employer and
Plan Participants.

This Plan is sponsored by:

   KeyCorp, on behalf of its operating subsidiaries, banking and trust company 
   affiliates
   127 Public Square
   Cleveland, Ohio  44114
   (800) 982-3811

<PAGE>

In Witness  Whereof,  the  Employer and the Trustee,  by their  respective  duly
authorized officers,  have caused this Adoption Agreement to be executed on this
7th day of April, 1998.


Employer:  Helix Technology Corporation
 

By:       /s/ Michael El-Hillow
          ---------------------
          Michael El-Hillow
Title:    Senior Vice President and CFO

Trustee:  Key Trust Company of Ohio, NA

 
By:       /s/Michael Olah
          ---------------------
          Michael Olah
Title:    V.P.

            and

By:       /s/Anthony Feora
          ----------------------
          Anthony Feora



Approved on Behalf of Trustee:

                                Initials:   /s/M.O.     Date:  4/7/98
                                            -------
                                            M.O.





                           Investment Fund Designation
<PAGE>

Helix  Technology  Corporation  (the  "Named  Fiduciary"),   as  an  independent
fiduciary with respect to the Helix Technology Corporation Employee Savings Plan
& Trust (the "Plan"), an employee pension benefit plan covered by the applicable
provisions of the Employee  Retirement  Income  Security Act of 1974, as amended
("ERISA") and its employees who participate therein (the "Participants"), hereby
designates the following investment funds from among the investment fund options
available for adopting employers of the PRISM Prototype  Retirement Plan & Trust
(as  defined  in  Section  10.7  of  the  Plan),   available  for  selection  by
Participants for the investment of Plan assets held for their benefit:

              (a)   EB MaGIC Fund
              (b)   Fidelity ContraFund
              (c)   Fidelity Magellan Fund
              (d)   The American Funds Group: American Balanced Fund
              (e)   The Victory International Growth Fund: Class A
              (f)   Helix Technology Corporation
              (g)
              (h)
              (i)
              (j)
              (k)
              (l)
              (m)

The plan assets are currently  invested in the funds more fully  described below
(Existing  Funds).  The Named Fiduciary  further  designates that assets held in
each of the Existing Funds by the Plan prior to liquidation  and transfer to the
Trustee shall be reinvested in the PRISM Fund(s) as specified below:

      Existing Funds:                           PRISM Funds:
 (a)                                (a)   EB MaGIC Fund
 (b)                                (b)   Fidelity ContraFund
 (c)                                (c)   Fidelity Magellan Fund
 (d)                                (d)   The American Funds Group: American 
                                          Balanced Fund
 (e)                                (e)   The Victory International Growth Fund:
                                          Class A
 (f)                                (f)   Helix Technology Corporation
 (g)                                (g)
 (h)                                (h)
 (i)                                (i)
 (j)                                (j)
 (k)                                (k)
 (l)                                (l)
 (m)                                (m)
  X  In addition, if selected, an Employer Stock Fund will also be available.

(EBMaGIC,  Fidelity  Magellan  and  The  American  Funds  Group  are  registered
trademarks.)



<PAGE>

In making the selection of Investment  Funds, and in designating the PRISM Funds
into  which the  liquidated  assets  from  each of the  Existing  Funds  will be
invested in, the Named Fiduciary hereby confirms and acknowledges that:

The Named Fiduciary has had made available to it copies of the  prospectuses (to
the extent required under applicable  federal securities law and regulation) for
each investment fund available for selection by adopting  employers of the PRISM
Prototype  Retirement  Plan &  Trust,  and has  received  copies  of  each  such
prospectus for the Investment Funds selected;  The Named Fiduciary  acknowledges
that the Trustee of the Plan may receive  certain fees for services  provide to,
or on behalf of an  Investment  Fund, or the sponsors or  distributors  thereof,
pursuant to plans of  distribution  adopted by the fund under the  provisions of
Rule 12b-1 of the Investment Company Act of 1940, and further  acknowledges that
(i) such fee, if paid, is  appropriate  for services  rendered to the fund,  and
when aggregated  with other fees for service payable to the Trustee  constitutes
reasonable  compensation  for the Trustee's  services to the Plan;  and (ii) the
Plan  will be  able to  redeem  its  interest  in any  such  Investment  Fund on
reasonably short notice without penalty;
The Named  Fiduciary  further  acknowledges  that it has selected the Investment
Funds on its  determination,  after due inquiry,  that the Investment  Funds are
appropriate  vehicles for the investment of Plan assets pursuant to the terms of
the Plan,  considering all relevant facts and  circumstances,  including but not
limited to (i) the  investment  policy  and  philosophy  of the Named  Fiduciary
developed  pursuant  to ERISA 404;  (ii) the ability of  Participants,  using an
appropriate mix of Investment  Funds, to diversify the investment of Plan assets
held for their benefit;  and, (iii) the ability of Participants to, utilizing an
appropriate mix of Investment Funds, to structure an investment portfolio within
their account in the Plan with risk and return characteristics within the normal
range of risk and return characteristics for individuals with similar investment
backgrounds, experience and expectations; and,
The Named Fiduciary  acknowledges that it has not relied on any  representations
or  recommendations  from the Trustee or any of its  employees in selecting  the
Investment  Funds, or in specifying which of the selected PRISM Funds into which
the liquidated assets from each of the Existing Funds will be invested.
<PAGE>

The Trustee  agrees to follow the Named  Fiduciary's  direction  with respect to
offering the Investment Funds available for selection by the Participants in the
Plan for the investment of Plan assets held for their benefit:

In Witness Whereof,  the Employer,  by its duly authorized  representative,  has
executed  this document in  connection  with adoption of the Plan  utilizing the
PRISM Prototype Retirement Plan & Trust documents, as provided by the Trustee.


                       Named Fiduciary:  Helix Technology Corporation



 
  By:     /s/Michael El-Hillow
          --------------------
          Michael El-Hillow

  Title:  Senior Vice President and CFO

<PAGE>


        <F1>   Footnotes  in this  Adoption  Agreement  are not to be  construed
as part of the  Plan  provisions  but are  explanatory  only.  To the  extent  a
footnote  is  inconsistent  with the  provisions  of the Basic Plan  Document or
applicable law, the provisions of the Plan shall be construed in conformity with
the Basic Plan Document or law.

        <F2>   Terms that are capitalized are defined in the PRISM Prototype 
Retirement Plan & Trust Basic Plan Document.

        <F3>   The Plan will have an individual TIN, distinct from the Employer
TIN.

        <F4>   Committee  members  direct  the  day to day  operation  of the 
Plan. Committee members serve at the pleasure of the Employer.  See Section 11.4
for changes in Committee membership.  If no Committee members are specified, the
Employer shall assume responsibility for the operations of the Plan.

        <F5>   If no amount is  specified,  the maximum  amount of  Compensation
allowed under Code Section  401(a)(17)(the  "$150,000 limit"  ("$200,000  limit"
prior to the Plan Year beginning before January 1, 1994)), as adjusted from time
to time, shall be used.

        <F6>   If a fractional  year is elected,  the elapsed time method of
computing service shall be used for the fractional year.  Eligibility provisions
for  optional  cash or deferred  arrangements  are  contained  in Item C of this
Adoption Agreement.

        <F7>   Notwithstanding  the  foregoing,   an  Employee  who has  met the
eligibility  requirements may not enter the Plan later than six months following
the date on which the Employee first completes the eligibility requirements.

        <F8>   Notwithstanding  the selection made in this Item B(7)(a), a 
participant shall be fully vested in his or her Employer  Contribution  Accounts
if the Participant dies or becomes Disabled while in the employ of the Employer.

        <F9>   If more than one Year of Service is an eligibility  requirement, 
Item viii must be selected.

        <F10>  The  provisions  of this  section  will be  administered  by the
Employer on a consistent and nondiscriminatory basis.

        <F11>  Amounts  designated as Qualified  Nonelective  Contributions will
be allocated pursuant to Section 3.1(A)(14) of the Basic Plan Document.

        <F12>  In the event contributions are allocated  on a basis  other  than
a full plan year,  the Year of Service shall be based on the elapsed time method
of  calculation,  and a  Participant  shall  be  deemed  to  have  completed  an
appropriate  Period of Service for allocation  purposes if the  Participant  has
completed a pro-rata  Period of Service  corresponding  to the interval on which
contributions are allocated.
<PAGE>

        <F13>  Excess  Compensation  means  a  Participant's  Compensation  in 
excess of the Permitted  Disparity Level specified in the Definitions section of
this Adoption Agreement.

        <F14>  Even if this Item  is  selected,  the  provisions  of Section 4.8
of the Basic Plan  Document  may  supersede  this  requirement  if  necessary to
satisfy Code Sections 401(a)(26) and 410(b).

        <F15>  If this option is  selected,  iii  or  iv  must  be  selected  to
reallocate Forfeitures of Employer Profit Sharing Contributions  remaining after
expenses of administering the Plan have been paid.

        <F16>  This Item is for use in identifying collective trust funds, 
which, pursuant to Revenue Ruling 81-100 must be specifically  referenced in the
Plan.  Actual Investment Funds are referenced on the Investment Fund Designation
form attached to this Adoption Agreement.

        <F17>  If this option is selected,  the Employer must establish 
appropriate procedures for implementation of the Plan's loan program.

        <F18>  The date  specified  is for the refund of amount  deferred in 
excess of the Code Section 402(g) limit (the $7,000 limit) for the Participant's
taxable year.

        <F19>  The Employer  shall have the right to designate  all, or any 
portion of Employer Matching Contributions as Qualified Matching  Contributions,
which shall then be subject to the same vesting,  distribution,  and  withdrawal
restrictions as Before Tax Contributions.

        <F20>  Net  Profits will  never be  required  for  the  contribution  of
Before  Tax  Contributions,  After  Tax  Contributions,   Qualified  Nonelective
Contributions or Qualified Matching Contributions.

        <F21>  Notwithstanding  anything in the Adoption Agreement to the 
contrary,  amounts  in  a  Participant's  account  attributable  to  Before  Tax
Contributions,  Qualified  Nonelective  Contributions,  and  Qualified  Matching
Contributions shall be 100% vested and nonforfeitable at all time.

        <F22>  Notwithstanding  the selection made in this item B(7)(b), a 
Participant shall be fully vested in his or her Employer  Contribution  Accounts
if the Participant dies or becomes Disabled while in the employ of the Employer.

        <F23>  The  provisions  of this  section  will be  administered  by the
Employer on a consistent and nondiscriminatory basis.


<PAGE>


                          Helix Technology Corporation
                          Employee Savings Plan & Trust

                                    Addendum

The following  items are in explanation or expansion of certain items  contained
on the Adoption Agreement or in the Basic Plan Document:

Item B(13):  411(d)(6) Protected Benefits:

Notwithstanding  anything  in the Plan to the  contrary,  pursuant to 7.8 of the
Plan, the following are 411(d)(6) protected benefits which shall be preserved in
the Plan and be available as options to the Participants:

Optional Form of Benefit Distribution

In addition to a lump sum payment,  Participants' benefit distributions shall be
payable by the purchase of a non-transferable fixed or variable annuity contract
that provides fixed income or fixed period payments.

Withdrawal  of Amounts  Attributable  to  After-Tax  Contributions  and  Company
Matching Contributions

A  Participant  may elect to withdraw  all or a portion of the then value of his
Participant  Account  attributable to his After-Tax  Contributions  and his vest
Company Matching  Contributions as of the Valuation Date coincident with or next
following the date such written  request is received by the Benefits  Committee;
provided, however, that:

      (a)   No  withdrawal  will be permitted  unless the amount to be withdrawn
is at least $350 or 100% of the then value of his  After-Tax  Contributions  and
vested Company Matching Contributions if less than $350;
      (b)   Any   withdrawal   under  this   addendum  will  require  a  
suspension of the  Participant's  Before-Tax and After-Tax  Contributions  for a
period of three months following the effective date of the withdrawal;
      (c)   In no event will a Participant be permitted to withdraw After-Tax
Contributions or vested Company Matching  Contributions held less than two years
except in the event of a hardship  (such as an accident,  sickness,  disability,
education of himself or immediate family,  purchase or capital  improvement to a
primary residence) approved by the Benefits Committee;
      (d)   Such  request  is  received  30 days prior to the  Valuation  Date
unless such advance  notice is waived by the Benefits  Committee.  The amount so
withdrawn  shall be paid to the  Participant as soon as practicable  thereafter;
and
      (e)   Notwithstanding  anything herein to the contrary,  any  withdrawals
made from a Participant's  Account  attributable to his After-Tax  Contributions
shall be made  first  from  that  portion  of his  Account  attributable  to his
After-Tax   Contributions  made  prior  to  January  1,  1987,  until  all  such
contributions  have been  withdrawn,  and then from the  portion of his  Account
attributable to such  contributions  made after December 31, 1986. In any event,
withdrawals from a Participant's Account attributable to After-Tax Contributions
and earnings thereon shall be made in a manner in which corresponds with the tax
treatment of the withdrawal under the Code.
<PAGE>


For purposes of this section,  the Benefits Committee shall determine in its
sole  discretion  whether a financial  hardship  exists to warrant a withdrawal,
and, if such hardship exists, the amount of the withdrawal necessary to meet the
hardship.

All other provisions of the Plan shall be unaffected by this addendum,  which
shall be given  force  and  effect  only to the  extent  necessary  to  preserve
411(d)(6)  protected  benefits  consistent  with the  provisions of the Code and
regulations issued thereunder.

Item B(15)(b)(i) - Investments Employer Stock Fund:

A Participant  will have the right ,  notwithstanding  any other  provisions of 
the Plan,  to direct  that all or any  portion of the Plan assets held for their
benefit and invested in the Employer Stock Fund be diversified  upon  attainment
of age 58.

Item B(15)(d) - Investments:

Participants  shall be restricted in making changes of existing account balances
attributable to assets held for their benefit and invested in the Employer Stock
Fund.

Item B(15)(f) - Investments:

Employer   Discretionary   Matching   Contributions   made  on  behalf  of  Plan
Participants will be invested in Employer Stock Fund.



Item C(7)(b) - In - Service Distributions:

Participants  will be restricted from receiving an in - service  distribution of
their  account   balance   attributable  to  Employer   Discretionary   Matching
Contributions.