Initial Report of Ownership - Robert Mahoney

This filing is an initial report of ownership for Robert John Mahoney, reporting his direct ownership of 13,472 shares of Common Stock in Axcelis Technologies Inc. as of December 19, 2025. The report also notes that 9,877 of these shares are subject to forfeiture upon vesting of restricted stock units granted under the 2012 Equity Incentive Plan. The filing also includes a Power of Attorney document, dated November 19, 2025, authorizing specific individuals to execute Section 16(a) reports on behalf of Robert Mahoney regarding Axcelis Technologies, Inc. securities.