A001 - Questions-Answers.pdf
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- Attached to
- Horizontal Dry Dilution Refrigerator Federal contract opportunity
- Solicitation number
- 1333ND23QNB680485
About this file
This document contains questions and answers regarding a request for quotation for a horizontal dry dilution refrigerator. The RFQ is seeking a custom cryogenic system to reach temperatures below 50 millikelvin, with specified cooling capacities and temperature control requirements. Acceptable materials are listed for radiation shielding components, and clarification is provided regarding the mounting and thermal connection of signal amplifiers to the 40K stage. Filtering requirements are defined for resistive thermometers, with calibration needed for an additional mixing chamber sensor. Training will be conducted at the shipment destination of Brookhaven National Labs, rather than the stated location of NIST Boulder Labs. Quotations should be submitted electronically to the named contracting officer by the due date specified in the original solicitation posting on SAM.gov.
View the file
Other files for this federal contract opportunity
| File | Type | Posted |
|---|---|---|
| Specifications_v.2_8-24-2023.pdf | ||
| Attachment B - Experience Project Data Sheet.pdf | ||
| Atch A - Instructions_Evalution Criteria_Basis for Award.pdf | ||
| A001-1333ND23QNB680485 Horizontal Dry Dilution Refrigerator.pdf | ||
| Specifications.pdf | ||
| 1333ND23QNB680485 Horizontal Dry Dilution Refrigerator.pdf |
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Text version
QUESTIONS AND ANSWERS
AMENDMENT 1
• 1.2 Point 6 lists radiation shield requirements. Are there constraints on the materials used for the radiation shields, as you have specified for the vacuum can? We typically provide aluminum shields at the 40 and 4 K stages and copper shields at the still and mixing chamber.
o There are no constraints on shield material provided the cooling specifications are met.
● 1.6 Point 3 lists amplifiers which need to reach a temperature somewhat above 40 K.
Typically, we would expect these amplifiers to be mounted to the 40 K plate. If an additional stage is required to mount these amplifiers, and either a control loop is needed to maintain at a specified temperature or a mounting to the first stage regenerator, then this will add length to the design of the fridge with the addition of another intermediate amplifier mounting plate. What temperature do your amplifiers require, or can we maintain that these will be mounted to the 40 K plate?
o The amplifiers will be connected to the 40K stage by a female-female SMA connector. This SMA connector provides sufficient thermal resistance to allow the amplifier to reach the desired temperature with it’s own dissipated power. The mounting brackets should provide mechanical support without significant thermal conduction so that the highest conductance thermal connection is the SMA connector.
● 1.7 Point 1 states that electrical connections to the resistive thermometers shall be filtered to prevent electromagnetic interference. ZPC typically filters the mixing chamber thermometer as it is the only one that requires such filtering. Resistive heating from electronic noise at the higher temperature stages is typically negligible because of their lower resistance, twisted pair wiring, and use of the Lakeshore thermometry bridge. Is filtering the resistive thermometers on the mixing chamber plate sufficient, or do you require all of the thermometers filtered in this way?
o The filtering described here is sufficient, provided the other temperature specifications are met with that filtering.
● 1.7 Point 4 asks ZPC to list the option for an additional mixing chamber thermometer. Do you require this mixing chamber thermometer to be calibrated or uncalibrated?
o Calibrated.
● Testing and Acceptance Point 3 lists two days of training for at least 2 NIST personnel at NIST Boulder Labs; however this unit is being shipped to Brookhaven National Labs. We are looking to confirm whether this is an error or if we need to send two technicians to your facilities in Boulder, Colorado.
o This is an error, the training will occur at the location the cryostat is shipped to.
Further, please see the below question regarding the submission of the above-noted RFQ:
● Regarding bid submission, the Terms & Conditions mention an approved e-commerce method of online submission. Is it possible to submit online via email (or another method), or is it best to Express ship you ZPC’s bid?
o Per the RFQ, please submit the quotation to patricia.rose@nist.gov by the quotation due date in the SAM.gov posting.
mailto:patricia.rose@nist.gov
File details come from the government source that posted it. Updated .