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Cryogenics system overview

The cryogenics system is comprised of the following components:

Dilution refrigerator: (to be purchased)

Cryocooler
Compressor for cryocooler operation
Thermal shields and heat exchangers
Gas pumping/handling system for driving 3He circulation
Support Structure

Mixing chamber plate

Cold plate

Still plate

4K shield

flange

50K shield

flange

50 K

4 K

0.7 K

100 mK

10 mK

Upper canisters: (to be fabricated)

50 K upper canister
4 K upper canister
Still-plate upper canister
Cold-plate upper canister
MXC upper canister

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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Cryogenics system overview

The cryogenics system is comprised of the following components:

Payload canisters and payload box plates: (to be fabricated)

50 K payload canister and box plate
4 K payload canister and box plate
Still payload canister and box plate
Cold payload canister and box plate
MXC box plate

Upper canister

Payload box plate

Payload canister

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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Table of contents

Cryogenics system overview

System requirements

Cost estimation

Acquisition schedule

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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System requirements

ID	Requirement Name	Requirement Text
TE-CRY-1	Material Requirements for internal canisters	The internal radiation shielding canisters shall be XX to meet background requirements. Thermal performance?
TE-CRY-2	Cryostat Dimensions to fit Warm Shielding	The internal cryogenic shielding canisters shall be defined by drawing DWG#X. This will ensure that they fit within the warm shielding and vacuum canister without interference.
TE-CRY-3	Accomodation of Detector Auxiliary Equipment.	- Squid cards (stage 1 and stage 2) as defined in DOC#X�- HEMTs�- He supply and return lines�- etc.
TE-CRY-4	Payload/Detector Weight Capacity	The dilution refrigerator has a limited weight capacity, and needs to accommodate cryogenic shielding, backgrounds shielding. This leads to an allowable detector payload weight of XX kgs.
TE-CRY-5	Heat Dissipation Load of Detectors	The dilution refrigerator shall be sized to dissipate the thermal loads imposed by the detectors, as defined in DOC#X
TE-CRY-6	Heat Conduction Load of Detector Cabling	Heat loads induced by electronics, including detectors, HEMTs, SQUIDs, and cabling, should be carefully analyzed.
TE-CRY-7	Temperature Difference Between Detectors and Mixing Chamber Plate	The design should ensure that the temperature difference between the MXC fridge and the MXC box remains below 1 mK.
TE-CRY-8	Internal background shielding	Lead block dimensions to be XXmm by XXmm�Copper Still Chamber dimensions to be Xmm by Xmm by X mm
TE-CRY-9	Payload Access	The payload canisters shall be designed to be opened and closed to swap detector elements.
TE-CRY-10	Payload Access Frequency	The Payload canisters will be designed to allow for an open/close cycle on a monthly basis.
TE-CRY-11	Upper Dilution Refrigerator Access	The canister design shall allow for complete disassembly and access to the dilution refrigerator internals.
TE-CRY-12	Vibration Isolation of the Dilution Refrigerator	External and internal vibration isolation

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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System requirements

Radiation shields requirements: (Yinghe Qi)

There should be enough gap between shielding canisters and payload boxes.
Thermal contraction should be considered in the design.

Space for detectors and readout cables.

Space for installing readout electronics (Squid cards, stage 1 and stage 2).
Arrangement of cables through the narrow gaps between canisters.
Enough experimental space in the payload box.

All the radiation shields fit the vacuum vessel and do not interfere with each other.

The design of the canisters must allow: 1) easy access to the detector elements; 2) easy access to all dilution refrigerator internal components

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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System requirements

Thermal requirements: (Yinghe Qi)

Mixing chamber plate

Cold plate

Still plate

4K shield

flange

50K shield

flange

50 K

4 K

0.7 K

100 mK

10 mK

Temperatures of radiation shielding canisters and boxes must meet refrigerator and detector operation requirements.

Heat load from detectors and cables (TES and SQUID readout cables) can be managed by the dilution refrigerator.

Need to determine suitable locations for heat sinking detectors and cables.

T (K)

Suitable materials and geometry (thickness) to ensure sufficiently small thermal resistance.
Interface resistance should be sufficiently small

R. L., Schmitt, et al, Cryogenics, 70, 41 (2015)

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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System requirements

Fridge selection: (Scott A. Hertel)

The dilution refrigerator must be able to sustain the weight of the following items:

Radiation shielding canisters and boxes
Internal background shielding (lead shielding disc)
Payload copper box

Gamma Ray shielding: (Bjoern Penning)

Internal lead disc shielding and copper box shielding should suppress background events to below targeted threshold

Vibration isolation and support structure (Matt Pyle):

Fridge vibration suppression: vibration isolation frame, placing compressor in separate room at sufficient distance, etc.

Internal vibration isolation system.

Cooling power at 4K, 1K, cold plate, and MXC

Other factors: quality, service, costs

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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Table of contents

Cryogenics system overview

System requirements

Cost estimation

Acquisition schedule

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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Cost estimation

Dilution refrigerator system:

Dilution refrigerator
Gen-2 Gas handling system
Compressor for cryocooler
Compressor for driving 3He/4He flow
Reinforced internal support structure (rated: up to 350 kg to 4K plate; up to 300 kg to Still plate.)

Estimated subtotal: $600k USD

Dilution refrigerator support:

Fridge support frame ($10,000)
Compressor cabinets ($4,000)
Closed cooling water loop ($5,000)
Internal OFE copper ($10,000)
N2 cold trap ($1,000)
20L 3He ($20,000)

Estimated subtotal: $50k USD

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Drive System • CDR 2024

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Cost estimation

Shields and miscellaneous:

Shields: upper canisters, payload canisters, and payload box plates ($150k USD)

Estimated subtotal: $160k USD

Ricochet has an OVC, 50K, 4K, 1K thermal shields in three parts (total length ~1.5 meter) 🡪 80k Euros

Our design has complex neck parts that need to be welded

Our design has an additional shielding at 100 mK (cold plate)

Thermal straps ($4k)

Thermometers ($1k/each x 6 = $6k)

Estimated total cost:

$600k + $50k + $160k = $810k

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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Table of contents

Cryogenics system overview

System requirements

Cost estimation

Acquisition schedule

Presentation Title | BERKELEY LAB

Drive System • CDR 2024

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Acquisition schedule

	2025 (2^nd half)	2026 (1^st half)	2026 (2^nd half)	2027 (1^st half)	2027 (2^nd half)
Complete Cryo Design
Cryo FDR
Dil Fridge PRR
Order Dil Fridge
Order fridge peripheries: 3He, thermal straps, thermometers, etc.
Fridge Testing and Commissioning
Fabricate canister shields
Commission the full TE cryogenic and fridge assembly

Presentation Title | BERKELEY LAB

Drive System • CDR 2024