(a) In general The Director may, in accordance with applicable provisions of title 5, appoint and determine the compensation of such employees as the Director determines to be necessary to carry out the duties of the Institute. (b) Appointment and compensation of technical and professional employees (1) In general Subject to paragraph (2), the Director may appoint without regard to the provisions of title 5 governing the appointment in the competitive service and may compensate without regard to the provisions of chapter 51 or subchapter III of chapter 53 of such title (relating to the classification and General Schedule pay rates), such technical and professional employees as the Director determines to be necessary to carry out the duties of the Institute. (2) Number and compensation The number of employees appointed and compensated under paragraph (1) shall not exceed 1/5 of the number of full-time regular or professional employees of the Institute.

The rate of basic compensation for the employees appointed and compensated under paragraph (1) may not exceed the rate prescribed for level GS-15 of the General Schedule under section 5332 of title 5. (c) Voluntary services The Director may accept and utilize the voluntary services of individuals and reimburse the individuals for travel expenses, including per diem in lieu of subsistence, in the same amounts and to the same extent as authorized under section 5703 of title 5 for persons employed intermittently in Federal Government service.