Mass. Gen. Laws ch. 32 § 66
Any court officer of the supreme judicial or superior court who, in the judgment of the sheriff of his county, is disabled for useful service in either of said courts, and who is certified by a physician, designated by the sheriff, to be permanently incapacitated, either mentally or physically, by injuries sustained through no fault of his own, in the actual performance of his duty in said court, and any court officer of either of said courts who has performed faithful service in either or both of said courts for not less than twenty years, and who in the judgment of the sheriff of his county is incapacitated for further service in said courts, shall, if the sheriff so requests, with the approval of a majority of the justices of the court in which he serves, be retired, and shall annually receive a pension equal to one half of the compensation received by him at the time of his retirement.
No court officer whose employment begins after June thirtieth, nineteen hundred and thirty-seven, shall be subject to the provisions of this section.
Mass. Gen. Laws ch. 32, § 66