Description
The National Institute of Standards and Technology (NIST) is seeking a 4K Cryogen Free Cryostat for use in a metrology setting to disseminate the SI volt for dc and ac electrical applications. The cryostat should meet specific technical requirements, including having a water-cooled compressor, consuming no more than 8 kW, and having a second stage cold plate with a minimum outer diameter of 8 inches. The contractor shall deliver a quantity of one cryostat with required accessories and add-ons. The cryostat should be new, not used or remanufactured, and should not include "gray market" components. The contractor may also bid on optional items, including additional RF coaxial wiring, additional miniature coaxial wiring, and a vacuum pumping system. The delivery terms are FOB Destination, and the contractor shall be responsible for any loss or damage to the goods before receipt and acceptance by the consignee.
Key features and requirements of the cryostat include:
* No additional cryogens required by the user after delivery
* Water-cooled compressor consuming no more than 8 kW
* Flexible lines between the compressor and coldhead that are at least 5 meters long
* Electrical isolation between the compressor and coldhead
* Second stage cold plate with a minimum outer diameter of 8 inches
* Second stage sample space with a minimum vertical length of 5 inches
* Minimum cooling power at the second stage of 500 mW at 4.2 K
* Maximum base temperature at the second stage of 3.5 K
* Maximum peak-to-peak temperature fluctuations at the second stage of 5 mK
* At least two thermometers, one mounted to the first stage and one at the second stage
* A heater mounted to the second stage
* A temperature controller for maintaining temperature at the second stage using a PID control loop
* A thermal radiation shield mechanically and thermally coupled to the first stage
* Passive magnetic shielding that attenuates the Earth's stray field at the sample space by at least a factor of 100
* At least four BeCu 0.086” OD semirigid RF coaxial lines between room temperature vacuum flange and second stage
* At least eight electrically isolated (floating) 0.047” OD semirigid coaxial lines between room temperature vacuum flange and second stage
* At least one 25-way cryogenic woven loom cable between room temperature vacuum flange and second stage
* At least two vacuum port blanks for custom instrumentation wiring
The contractor shall provide a system that meets all technical specifications, and the government reserves the right to perform performance tests and evaluations to verify system performance.