BZ-2025-13 TESSERACT.pdf

LBNL Request for Information No. BZ-2025-13 Page 1

August 27, 2025

Subject: Request for Information (RFI) No. BZ-2025-13 Response Due Date: September 11, 2025

Introduction The University of California, Lawrence Berkeley National Laboratory (LBNL) is conducting market research to identify sources that possess the capabilities and experience necessary to provide a dilution refrigeration system for a low-temperature application.

Background The Physics Division at LBNL is leading an international effort to construct and operate a new dark matter detector experiment utilizing low-temperature Transition-Edge Sensor (TES) technology, in conjunction with Laboratoire de Physique Subatomique et de Cosmologie (LPSC) in France. Two identical dilution refrigerator systems are needed for the experiment. One will be purchased by LPSC and one by LBNL.

The TESSERACT project involves the development of a highly sensitive low-temperature detector system aimed at probing extremely rare physical events. To achieve the necessary performance, the system must operate at temperatures on the order of 10 mK while also minimizing radioactive backgrounds. This dual requirement presents a unique set of technical challenges for the dilution refrigerator design. Specifically, the detector target and sensors must be enclosed within layered shielding enclosures to suppress environmental radiation. To integrate with these enclosures, the refrigerator must be equipped with shielding cans that feature a narrow-necked geometry. This allows the lower section housing the detector to extend into a pre-installed room-temperature shielding assembly. Additionally, internal shielding materials must be incorporated into the refrigerator itself, resulting in substantial static loads on the cold plate and mixing chamber.

The LBNL-purchased dilution refrigerator will first be commissioned at the University of California, Berkeley, and will later need to be transported to the experiment site in Modane, France.

Preliminary Specifications LBNL intends to acquire an instrument that meets or exceeds the following specifications. These are preliminary and subject to change. We are assuming a cooling solution based on pulse-tube technology.

1. Cryogenic Performance

● Base temperature: <10 mK on the mixing chamber plate (goal: 8 mK).

● Stage temperatures:

o Cold plate: <100 mK o Still plate: <1 K o 4K stage: <4.2 K o 60K stage: <70 K

● Cooling power at the cold plate (mixing chamber lower than 14 mK): ≥320 µW.

● Cooling power at the mixing chamber stage (stabilized at 20 mK): ≥12 µW.

● Cooling power at the mixing chamber stage (stabilized at 100 mK): ≥450 µW.

LBNL Request for Information No. BZ-2025-13 Page 2

● Temperature control: Mixing chamber plate must be controllable up to 30 K with the pulse tube temperature at 4.2 K

● Pulse tube cooler should have a cooling power >1.3 W at 4.2 K

● Electrical isolation: Complete galvanic isolation from gas-handling system and pulse tube compressor (>1 GΩ).

2. Mechanical Load Requirements

Thermal stages must support the following payloads, including detector modules and shielding:

● 300 K stage: ≥550 kg

● 50 K stage: ≥390 kg

● 4 K stage: ≥355 kg

● Still stage: ≥325 kg

● Cold plate stage: ≥110 kg

● Mixing chamber stage: ≥60 kg

3. Vibration Requirements

The pulse tube cold head should be mechanically decoupled from the cryostat frame at room temperature with the use of an edge-welded bellows and a dedicated frame for maximum decoupling.

4. Mechanical Structure and Integration

Please refer to the picture below for the naming convention used in the following text.

● Payload still canister:

o The inner diameter of the payload still canister needs to be at least 285 mm in diameter and at least 458 mm high to ensure sufficient experimental volume.

o The support flange of the payload still canister should be at least 25 mm thick, have a 395 mm diameter, and have a bolt circle diameter of 365 mm to mate to the canister below. It needs to support a 130-kg load with less than 1.0 mm of deformation.

o The inner dimensions of the payload 4K canister need to be at least 415 mm in diameter and 535 mm in height to allow the space for a customer-provided thicker still canister.

● Payload vacuum canister (outer vacuum chamber):

o Outer diameter of the canister (not including flange diameter) between 490 mm and 530 mm o Outer height (from bottom to flange mating surface) between 590 mm and 630 mm.

o The bottom of the outer vacuum chamber shall be a distance from the support platform either 680 mm or equal to the height of the outer vacuum chamber plus 2.5 cm, whichever is greater.

● Neck stage geometry (must match shielding interface):

o Outer diameter of the neck region between 162 mm and 202 mm.

o Height (from upper to lower flange mating surfaces) between 470 mm and 510 mm.

o The 10 mK cold finger and 100 mK neck must extend a prescribed distance into the payload still canister as follows:

▪ Distance from bottom of 10 mK flange to payload still plate mating surface:

125 mm

LBNL Request for Information No. BZ-2025-13 Page 3

▪ Distance from bottom of 100 mK flange to payload still plate mating surface:

30 mm o The thickness of the 100 mK cold neck needs to be at least 2 mm (for thermal reasons to support later customer heatloads). Greater thicknesses would be much appreciated if practical.

● The following clearances are required for routing of readout cables and tubing for the detectors:

o The distance between the bottom of the mixing chamber plate and the top of the extended mixing chamber plate is at least 100 mm.

o The distance between the top surface of the still canister flange above the neck and bottom of the extended cold plate is at least 20 mm.

o The inner diameter of the cold neck needs to be at least 57 mm.

o The radial distance between the inner diameter of the still neck and the outer diameter of the cold neck needs to be at least 20 mm. To state this a different way, the still neck inner diameter must be 40 mm larger than the cold neck outer diameter.

● Holes for the feeding through of customer wiring and tubing must be present in the extended cold plate, the payload cold flange, and the extended mixing chamber plate (with detailed locations and sizes of these holes to be specified by the customer).

● The mounting frame must be non-magnetic.

● The mounting frame must accommodate below it a (customer provided) warm shield of 1700 mm width. The frame must be open on all four sides: two sides to allow shielding movement, the other two sides to allow access to the cryostat when the shield is open.

● Total system height must fit within a lab space of ceiling height 3.6 m.

5. Additional System Requirements

● Equipment must be primarily suited for French electrical standards. LBNL is interested in support that can be provided for initial operation in the US as well.

● Thermometry: At least 8 calibrated sensors (MC, CP, Still, 4 K, 50 K, detector plate).

● Automated control: Automatic cool-down and warm-up procedures.

● Monitoring and logging: Full temperature/pressure readout exportable to external database.

● Safety and recovery: Automatic mixture recovery under fault conditions.

● Option to facilitate and handle the disassembly, transport and re-assembly from UC Berkeley to

France c. 2028.

LBNL Request for Information No. BZ-2025-13 Page 4

NAICS Code and Size Standard The North American Industry Classification System (NAICS) Code for this acquisition will be 334516 (Analytical Laboratory Instrument Manufacturing). The corresponding small business size standard is 1,000 or fewer employees.

Instructions Respondents who can demonstrate a proven record of delivering a dilution refrigerator per the preliminary specifications above should email the LBNL Procurement Representative Brian Zatkow at bzatkow@lbl.gov with any and all relevant published product literature and/or technical specifications demonstrating compliance. A list of similar previous jobs should be included, but contact information for previous customers is not required. Attachments or hyperlinks are both acceptable. Please state if the dilution refrigerator qualifies as a domestic end product under FAR Clause 52.225-1, Buy American Act - Supplies. Budgetary estimates are welcome but not necessary.

All responses must be submitted by email no later than 3:00pm Pacific on Thursday, September 11, 2025.

mailto:bzatkow@lbl.gov

LBNL Request for Information No. BZ-2025-13 Page 5

Request for Information Only This RFI is for informational and planning purposes only. This is not a request for quote or proposal. It does not constitute a solicitation and shall not be construed as a commitment by the University. Responses in any form are not offers and no subcontract will be awarded as a result of this announcement. No inquiries regarding a bid package or solicitation will be answered, because there is no bid package or solicitation yet available. Any information submitted by respondents to this RFI is strictly voluntary.

In order to protect the procurement integrity of any future procurement that may arise from this RFI, information regarding the technical point of contact will not be given and no appointments for presentations will be made. No funds are available to pay for preparation of responses to this announcement, and no reimbursement will be made for any costs associated with providing information in response to this RFI or any follow-up information requests related to this RFI. Responding to this RFI does not provide any advantage or disadvantage to potential offerors if LBNL chooses to issue a formal solicitation at a later date.

This Request for Information is governed by procurement policies and procedures established under the University's Prime Contract with the U.S. Government, represented by the Department of Energy, for management and operation of LBNL.

Proprietary Information Because information received in response to this RFI may be used to structure future programs and may be made available to the public, respondents must not include any information in their responses that might be considered business sensitive, proprietary, or otherwise confidential. Responses must be submitted with the understanding that their contents may be publicly disclosed and, in the event of a public disclosure, LBNL will not notify respondents or provide any opportunity to revise or redact submitted information.

Brian Zatkow LBNL Procurement Representative

(510) 495-2547 bzatkow@lbl.gov

(End of RFI document) mailto:bzatkow@lbl.gov

NAICS Code and Size Standard