Department of Commerce, Mountain Administrative Support Center, Acqusition Management Division, MC3, 325 Broadway, Boulder, Co 80303-3328

59 -- DILUTION REFRIGERATOR (SIC CODE 3679, CRYOGENIC COOLING DEVICE) SOL 52RANB90C013 POC Jan Beer, 303/497-6320 In the absence of other qualified sources, it is the intent of the National Institute of Standards and Technology (NIST) to acquire a dilution refrigerator for operation of a new capacitance standard based on single electron tunneling devices from Oxford Instruments, 45950 Hotchkiss Street, Fremont, CA 94539. The following are the Government's minimum requirements: Cooling power of at least 4 microwatts at 40 mK, in order to maintain this temperature while accommodating the heat load from the coaxial wiring used for the standard; very low vibration in order to eliminate microphonic noise; sufficient space for the standard and its wiring at the mixing chamber (at least 80 mm diameter and at least 150 mm tall), as well as for filters, attenuators, and other components at various locations; the size of the insert and dewar shall be such that the insert can be removed from the dewar with not more than 3.2m clearance above the floor; the liquid helium dewar shall not use a liquid nitrogen jacket; the variation Tmc with no heat applied to the mixing chamber shall not be more than plus-or-minus 0.5 mK; the usable liquid helium volume shall allow continuous operation of the DR for at least 30 hours between transfers of liquid helium; the liquid helium consumption rate shall not be more than 20 liters per day during continuous operation. The refrigerator for the new standard will be transported to various locations to demonstrate its capabilities. In order to facilitate repeated transport, and to minimize space requirements needed at each destination, the entire dilution refrigerator system shall be as compact and lightweight as possible. Reducing the size of a conventional system will not satisfy the requirements for cooling power and space. Therefore, the only proven way of accomplishing this is to eliminate the external pumps and gas handling system used for circulation in conventional systems and use internal sorption pumps. This acquisition is a commercial item acquisition. Interested concerns must submit a written qualification statement that clearly establishes the firm's capability to meet the above minimum requirements. This qualification statement shall be submitted to the individual and office cited above within 15 days from the date of publication of this synopsis. This is not a formal solicitation. See Note 22 except 45 days is changed to 15 days for commercial items. Posted 12/18/98 (W-SN281834). (0352)

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