EXHIBIT 10.140


THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933 AND MAY NOT BE RESOLD OR HYPOTHECATED BY THE HOLDER UNLESS SUCH
TRANSFER COMPLIES WITH AN EXEMPTION FROM THE REGISTRATION REQUIREMENTS OF SAID
ACT. ACCEPTANCE OF THIS NOTE CONSISTUTES THE HOLDER'S REPRESENTATION THAT THE
HOLDER TAKES THIS NOTE FOR INVESTMENT AND NOT WITH A VIEW TO RESALE OR
DISTRIBUTION.

                                                                     Note No. 01

                              UNSECURED CONVERTIBLE
                                 PROMISSORY NOTE

$1.00                                                              April 1, 2003
Irvine, California

      HiEnergy Technologies, Inc., a Delaware corporation ("Maker"), for value
received, hereby promises to pay YOCCA, PATCH & YOCCA, LLP, a California limited
liability partnership, or order ("Holder"), at 19900 MacArthur Blvd., Suite 650,
Irvine, California 92612, or at such other place as designated in writing by
Holder, the principal sum of One Dollars and No Cents ($1.00), with interest
thereon at the rate of ten percent (10%) per annum on the then outstanding
principal balance computed on the basis of a 365-day year and charged on the
basis of actual days elapsed minus thirty (30) days. The outstanding principal
balance, together with any and all accrued but unpaid interest shall all be due
and payable in full on or before 5:00 p.m., California time, September 15, 2003
(the "Maturity Date"). Interest shall accrue from and after the date of this
Unsecured Convertible Promissory Note ("Note"), payable in full on or before the
Maturity Date. All sums payable pursuant hereto shall be payable in lawful money
of the United States of America. Payments made under this Note shall be first
credited to fees or costs due under this Note, then to accrued interest and
lastly to outstanding principal. Unpaid interest shall be added to principal on
each anniversary of the date of this Note and bear like interest.

                              TERMS AND CONDITIONS


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      Section 1. Prepayment. Maker may prepay this Note in whole or in part,
without penalty, at any time and from time to time upon thirty days prior
written notice to Holder (the "Notice").

      Section 2. Default. If any of the following events (each hereinafter
called individually an "Event of Default") shall occur:

            (a) If Maker shall default in the payment of any amount on this Note
when the same shall become due and payable, whether at maturity or by
acceleration or otherwise, or otherwise default under this Note; or

            (b) If Maker shall make an assignment for the benefit of creditors;
or

            (c) If Maker shall file a voluntary petition in bankruptcy, or shall
be adjudicated a bankrupt or insolvent under the present or any future Federal
Bankruptcy Act or other applicable federal, state or other statute, law or
regulation; or

            (d) In the event of a liquidation, dissolution or winding up of the
Maker, whether voluntary or involuntary, or a sale, or a series of related
sales, of all or substantially all of the assets of the Maker, or a sale, or a
series of related sales, or exchange, of capital stock of the Maker, either by
the Maker or its shareholders, such that the Maker's shareholders immediately
before such transaction do not hold (by virtue of such shares or securities
issued solely with respect thereto) more than fifty percent (50%) of the voting
power of the surviving or continuing entity, or a merger, consolidation,
acquisition of property or shares, separation or reorganization of the Maker
with one or more entities, corporate or otherwise, as a result of which the
Maker is not the surviving corporation or as a result of which the holders of
stock of the Maker as of prior to the transaction do not hold (by virtue of such
shares or securities issued solely with respect thereto) more than fifty percent
(50%) of the voting power of the surviving or continuing entity; or

then, and in each and every such case, the Holder of this Note may by notice in
writing to the Maker declare all amounts under this Note to be forthwith due and
payable (except that, in the case of an Event of Default under either Section
2(b) or Section 2(c), this Note shall become immediately due and payable without
notice) and thereupon the balance shall become so due and payable, without
presentation, protest or further demand or notice of any kind, all of which are
hereby expressly waived. The Maker shall give promptly a written notice to
Holder of the occurrence or the approval by the Maker or its Board of Directors
of any and all of the foregoing events, and in any of the events under Section
2(d) or Section 2(e), such notice shall be given at least fifteen (15) days
prior to the anticipated effective date of the transaction. In addition, upon an
Event of Default, Holder may exercise any and all other rights and remedies
Holder has at law, in equity or otherwise. All remedies are cumulative. No
single or partial exercise of Holder of any right hereunder shall preclude any
other or further exercise thereof or the exercise of any other right.


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<PAGE>

      Section 3. No Waiver. No waiver by Holder of any default of breach by
Maker under this Note shall be implied from any delay or omission by Holder to
take action on account of such default if such default persists or is repeated;
no express waiver shall affect any default other than the default expressly made
the subject of the waiver and any such express waiver shall be operative only
for the time and to the extent therein stated. Any waiver of any covenant, term
or condition contained herein shall not be construed as a waiver of any
subsequent breach of the same covenant, term or condition. The consent or
approval by Holder to or of any act by Maker requiring further consent or
approval shall not be deemed to waive or render unnecessary the consent or
approval to or of any subsequent similar act.

      Section 4. Collection Costs. Maker covenants that, upon an Event of
Default, it shall pay to the person entitled to receive such payment such
further amount, to the extent lawful, as shall be sufficient to cover the cost
and expense of collection and enforcement of this Note, including reasonable
attorneys' fees and costs, court costs, costs of appeal and costs of collection
and enforcement of any judgment.

      Section 5. Successors/Liability. This Note shall be binding upon the
successors and assigns of Maker and shall inure to the benefit of Holder and its
successor and assigns. Diligence, demand, notice, presentment, notice of intent
to accelerate the maturity of this Note are waived by Maker. This Note shall be
governed by and construed in accordance with the laws of the State of
California.

      Section 6. Compliance with Law. It is Maker's and Holder's intention to
comply with any applicable usury law. In furtherance of this intention of Holder
and Maker, all agreements between Maker and Holder are expressly limited so that
in no event whatsoever shall the amount paid or agreed to be paid to Holder for
the use, forbearance or detention of money under this Note exceed the maximum
permissible under applicable law. If, for any reason whatsoever, fulfillment of
any provision hereof shall be prohibited by law, the obligation to be fulfilled
shall be reduced to the maximum amount so prohibited, and if for any reason
Holder should have received as interest an amount which would exceed the highest
lawful rate, such amount which would be in excess of the permitted interest
shall, at Holder's option, be applied to the reduction of principal of this Note
and not to the payment of interest, or be refunded to Maker. This provision
shall control any other provision of all agreements between Maker and Holder.

      Section 7. Transfer. Subject to the restrictions and limitations on
transfer under federal or state securities laws, upon surrender of this Note for
transfer or exchange, a new Note or new Notes of the same tenor, dated the date
to which interest has been paid on the surrendered Note and in an aggregate
principal amount equal to the unpaid principal amount of the Note so
surrendered, will be issued to and registered in the name of the transferee or
transferees.

      Section 8. Note Register. This Note is transferable only upon the books of
the Maker that Maker shall maintain for such purpose. The Maker may treat the
registered holder of this Note as he or it appears on the Maker's books at any
time as the Holder for all purposes.


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<PAGE>

      Section 9. Loss, Etc., of Note. Upon receipt of evidence satisfactory to
the Maker of the loss, theft, destruction or mutilation of this Note, and of
indemnity reasonably satisfactory to the Maker if lost, stolen or destroyed, and
upon surrender and cancellation of this Note if mutilated, the Maker shall
execute and deliver to the Holder a new Note of like date, tenor and
denomination.

      Section 10. Legal Representation. Yocca Patch & Yocca, LLP represents and
has represented Maker in specific matters, and has agreed at Maker's request to
accept payment in the form of this long-term Note rather than payment in cash
within 30 days, as is the normal practice. Maker's interests in this Note are,
or at least potentially are, adverse to those of the Holder. Maker understands
and acknowledges that (a) this Note is an unconditional obligation to pay the
indebtedness represented by this Note, plus interest at the maximum lawful rate,
unless converted at the Holder's option; (b) this Note is convertible into
securities of Maker at the option of the Holder; (c) this Note may be
accelerated in the events described in Section 2 of this Note; and (d) if unpaid
when due, the Maker shall be responsible to pay Holder's attorneys' fees and
costs of collection in addition to the amounts otherwise due. Maker has been
advised by Yocca Patch & Yocca to discuss this Note, before signing this Note,
with independent counsel of Maker's choice to be advised in regard to the
benefits, risks or any other aspect of this Note. Also, this Note is in an
amount equal to Yocca Patch & Yocca, LLP's billings as of a recent date, which
Maker has reviewed and approved prior to signing this Note.

      Section 11. Authorization. Maker represents and warrants to Holder that
the undersigned are duly elected and acting officers of Maker, holding the
offices indicated below, and duly and validly authorized by the Maker's Bylaws
to execute and deliver and cause the Maker to perform this Note without any
further corporate action.

      Section 12. Conversion. The Holder shall have the right to convert (the
"Conversion Right"), on the terms and conditions hereinafter set forth, the
principal amount and accrued interest, costs or other charges of this Note that
is then outstanding, in whole or in part, into a number of shares of Common
Stock, $.001 par value ("Stock") of the Maker equal to the result obtained by
dividing the principal amount of the Note then outstanding by One Dollar
($1.00), subject to adjustment as described below (the "Conversion Price"). The
period during which the Holder shall be entitled to elect to convert this Note
then outstanding, or any portion thereof, into Stock of Maker pursuant hereto
shall be from the date of this Note until the later of the date set for
prepayment by the Notice or the date of payment of this Note (the "Conversion
Period"). If Holder fails to make such election to convert the then outstanding
principal amount of this Note, in the manner hereinafter set forth, within the
Conversion Period, the Conversion Right granted hereunder shall terminate
automatically and be of no further force or effect with respect to the portion
of this Note so repaid. In the event Notice is withdrawn by Maker prior to
payment, or for any reason payment is not made on the date set in the Notice,
the Conversion Right granted under this Section1 shall not terminate and, the
Holder shall again have the Conversion Right granted under this Section with
respect to the principal amount of this Note then outstanding. If the Holder
desires to convert all or part of this Note, on the terms set forth in this
Section, into Stock, then, during the Conversion Period, the Holder must give
written notice to Maker of such Holder's election to convert this Note as
aforesaid, which election shall be irrevocable. Then, the Maker will cause one
or more stock certificates evidencing the Holder's ownership of the number of
Conversion Shares into which this Note has been converted as aforesaid to be
delivered promptly to the Holder against surrender to Maker of the original of
this Note or a replacement for a lost, stolen or destroyed Note. The Maker shall
cause the Conversion Price to be adjusted from time to time in case Maker shall
(i) pay a dividend or other distribution of shares of the Stock to the holders
of the outstanding shares of such class of Stock, (ii) subdivide the outstanding
shares of the class of Stock into which this Note is convertible into a greater
number of shares, (iii) combine the outstanding shares of Stock into which this
Note is convertible into a smaller number of shares, or (iv) merge or otherwise
reorganize or reclassify the Stock. In the event of each of the foregoing, the
Conversion Price in effect immediately prior thereto shall be adjusted so that
the Holder of the Note thereafter surrendered for conversion shall be entitled
to receive the number of shares of Stock, or other shares or property, which he
would have owned or have been entitled to receive had the Note been converted
immediately prior to the happening of such event at the same aggregate
Conversion Price. An adjustment made pursuant to this Section shall become
effective immediately after the record date in the case of a dividend or
distribution and shall become effective immediately after the effective date in
the case of subdivision or combination. Such adjustments will be made
sequentially upon the happening of more than one of the events described above.


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<PAGE>

      IN WITNESS WHEREOF, Maker has caused this Note to be executed as of the
date set forth above.

                              HiEnergy Technologies, Inc.,
                              a Delaware corporation

                              By: /s/ Bogdan C. Maglich
                                  ------------------------------------------
                                  Bogdan C. Maglich, Chief Executive Officer


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