Mirion Technologies, Inc.

On September 30, 2025, the Company completed its previously announced private offering (the “Convertible Notes Offering”) of $375.0 million aggregate principal amount of 0.00% Convertible Senior Notes due 2031 (the “Notes”), which includes the exercise in full of the initial purchasers’ option to purchase up to an additional $50.0 million principal amount of Notes. The size of the Convertible Notes Offering was increased from the previously announced $250.0 million aggregate principal amount of Notes.

The Notes were issued pursuant to an indenture, dated September 30, 2025 (the “Indenture”), between the Company and U.S. Bank Trust Company, National Association, as trustee.

The Notes are general unsecured obligations of the Company and will mature on October 1, 2031, unless earlier converted, redeemed, or repurchased. The Notes do not bear regular interest, and the principal amount of the Notes does not accrete. Special interest will accrue on the notes in the circumstances and at the rates described in the Indenture. The Notes are convertible at the option of the holders at any time prior to the close of business on the business day immediately preceding July 1, 2031, only under the following conditions: (1) during any calendar quarter commencing after the calendar quarter ending on December 31, 2025 (and only during such calendar quarter), if the last reported sale price of the Class A common stock, for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price for the Notes on each applicable trading day; (2) during the five business day period after any ten consecutive trading day period (the “Measurement Period”) in which the trading price (as defined in the Indenture) per $1,000 principal amount of Notes for each trading day of the Measurement Period was less than 98% of the product of the last reported sale price of the Class A common stock and the conversion rate for the Notes on each such trading day; (3) if the Company calls such Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date, but only with respect to the Notes called (or deemed called) for redemption; or (4) upon the occurrence of specified corporate events as set forth in the Indenture. On or after July 1, 2031, until the close of business on the second scheduled trading day immediately preceding the maturity date, holders of the Notes may convert all or any portion of their Notes at any time, in integral multiples of $1,000 principal amount, at the option of the holder regardless of the foregoing conditions. Upon conversion, the Company may satisfy its conversion obligation by paying or delivering, as the case may be, cash, shares of Class A common stock or a combination of cash and shares of Class A common stock, at the Company’s election, in the manner and subject to the terms and conditions provided in the Indenture.

The conversion rate for the Notes is initially 34.6951 shares of Class A common stock per $1,000 principal amount of Notes, which is equivalent to an initial conversion price of approximately $28.82 per share of Class A common stock. The initial conversion price of the Notes represents a premium of approximately 35% above the public offering price per share of the Class A common stock in the Common Stock Offering. The conversion rate for the Notes is subject to adjustment in some events in accordance with the terms of the Indenture but will not be adjusted for any accrued and unpaid special interest. In addition, following certain corporate events that occur prior to the maturity date of the Notes or if the Company delivers a notice of redemption in respect of the Notes, the Company will, under certain circumstances, increase the conversion rate of the Notes for a holder who elects to convert its Notes in connection with such a corporate event or convert its Notes called (or deemed called) for redemption in connection with such notice of redemption, as the case may be.

The Company may not redeem the Notes prior to October 5, 2028. The Company may redeem for cash all or any portion of the Notes (subject to the partial redemption limitation described below), at its option, on or after October 5, 2028, if the “liquidity condition” (as defined in the Indenture) is satisfied and the last reported sale price of the Class A common stock has been at least 130% of the conversion price for the Notes then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid special interest, if any, to, but excluding, the redemption date. If the Company redeems less than all the outstanding Notes, at least $100.0 million aggregate principal amount of Notes must be outstanding and not subject to redemption as of, and after giving effect to, delivery of the relevant notice of redemption. No sinking fund is provided for the Notes.

If the Company undergoes a fundamental change (as defined in the Indenture), then, subject to certain conditions and except as described in the Indenture, holders may require the Company to repurchase for cash all or any portion of their Notes at a fundamental change repurchase price equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid special interest, if any, to, but excluding, the fundamental change repurchase date.

The Indenture includes customary covenants and sets forth certain events of default after which the Notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving the Company after which the Notes become automatically due and payable. The following events are considered “events of default” under the Indenture:

•default in any payment of special interest on any Note when due and payable and the default continues for a period of 30 days;

•default in the payment of principal of any Note when due and payable at its stated maturity, upon optional redemption, upon any required repurchase, upon declaration of acceleration or otherwise;

•failure by the Company to comply with its obligation to convert the Notes in accordance with the Indenture upon exercise of a holder’s conversion right, and such failure continues for three business days;

•failure by the Company to give (i) a fundamental change notice or notice of a make-whole fundamental change, and such failure continues for five business days or (ii) notice of certain specified corporate events, and such failure continues for three business days;

•failure by the Company to comply with its obligations in respect of any consolidation, merger or sale of assets;

•failure by the Company to comply with any of the other agreements in the Indenture for 60 days after receipt of written notice of such failure from the trustee or the holders of at least 25% in principal amount of the Notes then outstanding;

•default by the Company or any of its significant subsidiaries (as defined in the Indenture) with respect to any mortgage, agreement or other instrument under which there may be outstanding, or by which there may be secured or evidenced, any indebtedness for money borrowed with principal amount in excess of $66.3 million (or its foreign currency equivalent), in the aggregate of the Company and/or any of the Company’s significant subsidiaries, whether such indebtedness now exists or shall hereafter be created, (i) resulting in such indebtedness becoming or being declared due and payable prior to its stated maturity date or (ii) constituting a failure to pay the principal of any such indebtedness when due and payable (after the expiration of all applicable grace periods) at its stated maturity, upon required repurchase, upon declaration of acceleration or otherwise, and in the cases of clauses (i) and (ii), such acceleration shall not have been rescinded or annulled or such failure to pay or default shall not have been cured or waived, or such indebtedness is not paid or discharged, as the case may be, within 45 days after written notice to the Company by the trustee or to the Company and the trustee by holders of at least 25% in aggregate principal amount of the Notes then outstanding in accordance with the Indenture; and

•certain events of bankruptcy, insolvency or reorganization of the Company or any of the Company’s significant subsidiaries.

If certain bankruptcy and insolvency-related events of default occur with respect to the Company, the principal of, and accrued and unpaid special interest, if any, on, all of the Notes then outstanding shall automatically become due and payable. If an event of default with respect to the Notes, other than certain bankruptcy and insolvency-related events of default with respect to the Company, occurs and is continuing, the trustee, by notice to the Company, or the holders of at least 25% in principal amount of the outstanding Notes by notice to the Company and the trustee, may declare 100% of the principal of, and accrued and unpaid special interest, if any, on, all the outstanding Notes to be due and payable. Notwithstanding the foregoing, the Indenture provides that, to the extent the Company so elects, the sole remedy for an event of default relating to certain failures by the Company to comply with certain reporting covenants in the Indenture will, for the first 365 days after the occurrence of such an event of default, consist exclusively of the right to receive special interest on the Notes.

The Indenture provides that the Company shall not consolidate with or merge with or into, or sell, convey, transfer or lease all or substantially all of the consolidated properties and assets of the Company and its subsidiaries, taken as a whole, to, another person (other than any such sale, conveyance, transfer or lease to one or more of the Company’s direct or indirect wholly owned subsidiaries), unless: (i) the resulting, surviving or transferee person (if not the Company) is a “qualified successor entity” (as defined in the Indenture) organized and existing under the laws of the

United States of America, any State thereof or the District of Columbia, and such qualified successor entity (if not the Company) expressly assumes by supplemental indenture all of the Company’s obligations under the Notes and the Indenture; and (ii) immediately after giving effect to such transaction, no default or event of default has occurred and is continuing under the Indenture.

The net proceeds from the Convertible Notes Offering, after deducting the initial purchasers’ discounts and estimated offering expenses, were approximately $365.2 million. The Company expects to use the net proceeds from the Convertible Notes Offering, together with the net proceeds from the Common Stock Offering, to (i) pay the approximately $38.0 million cost of the capped call transactions entered into with the Option Counterparties and (ii) fund the Acquisition, with the remainder for general corporate purposes. If the Acquisition is not consummated for any reason, the Company expects to use any net proceeds from the Convertible Notes Offering, together with the net proceeds from the Common Stock Offering, remaining after payment of the cost of the capped call transactions, for general corporate purposes.

The foregoing description is qualified in its entirety by reference to the text of the Indenture and the form of the Notes, which are attached as Exhibits 4.1 and 4.2, respectively, to this Current Report on Form 8-K and are incorporated herein by reference.