Bluefors coaxial wiring 2019

Coaxial Wiring

All our coaxial wiring options have been developed to operate reliably in the cryogenic environment of our systems and to survive repeated thermal cycling. Great care has been taken to thermally anchor the coaxial assemblies to our systems and at the same time optimize both their electrical and thermal properties. These efforts allows our systems to remain below 10 mK for close to all practical configurations of our factory installed wiring.
We offer a wide range of coaxial wiring solutions, from lossy Thermocoax wires with excellent high frequency filtering properties, to coaxial assemblies with high bandwidths. All our assemblies are manufactured in-house and go through testing before installation or shipping.

Standard coaxial wiring

  • Thermocoax
  • Flexible Grapho coaxial wire
  • Continuous CuNi-CuNi coaxial wire
  • Semi-rigid coaxial wires for high frequencies

Options

DC installation set

For proper thermalization and mounting of the gold plated copper bobbins we use a DC installation set. The DC installation set includes a hermetic feed-through connector box at room temperature and 1x aluminum and 4x gold plated copper thermal anchoring flanges for the 50K, 4K, still, Cold plate and mixing chamber stages with 3 or 4 feedthroughs.

RF installation set

For proper thermalization and mechanical anchor of the coaxial assemblies, we use RF installation sets for their installation. The RF installation set includes a hermetic feed-through at room temperature and 1x aluminum, 4x gold plated copper thermal anchoring flanges for the 50K, 4K, still, Cold plate and mixing chamber stages. The flanges comes with F/F bulkhead connectors for easy connection to the coaxial assemblies. There are available RF installation sets for KF40, KF63 and ISO-100 (XLD) LOS ports with different amount of feed-throughs.

RF components

We collaborate with Low-Noise Factory on integration of RF components. We have developed dedicated integration packages for amplifiers, isolators and circulators to interface with our wiring solutions. You save time and effort having the components integrated with the system. Integrated devices are covered by the manufacturers’ warranty.

Amplifiers

Cryogenic Low Noise Amplifier 4–8 GHz LNF-LNC4_8C
Cryogenic Low Noise Amplifier 0.3–14 GHz LNF-LNC0.3_14A

Isolators

4-8 GHz Cryogenic Single Junction Isolator LNF-ISC4_8A
4-8 GHz Cryogenic Dual Junction Isolator LNF-ISISC4_8A
4-8 GHz Cryogenic Triple Junction Isolator LNF-ISISISC4_8A

Circulators

4-8 GHz Cryogenic Circulator Isolator CIISC4_8
4-12 GHz Cryogenic Circulator Isolator CIISC4_12A

Technical Specifications

Thermocoax

For high frequency filtering, we offer sets of 12x Thermocoaxial wires from room temperature to the mixing chamber flange (continuous). These lines are anchored on each thermal stage by gold plated copper bobbins. One KF40 LOS-port can fit up 4x sets of 12x Thermocoaxial wires. The wires comes with SMA male connectors.

Material of the conductors: Austenitic SS-NiCr (80|20)

Note: Thermocoax wiring can have additional break-out at 4K flange to make installation of customer devices possible.

Note: Requires DC installation set

Continuous CuNi-CuNi coaxial wire

For low frequency signals we have the lossy CuNi coaxial wiring, which comes in a package of 6x continuous CuNi-.CuNi wires from room temperature to mixing chamber flange. These lines are anchored on each thermal stage by gold plated copper bobbins. In a KF40 LOS-port one can fit up four sets of 6x CuNi-CuNi wires. The wires comes with SMA male connectors.
Material of the conductors: CuNi-CuNi

Note: CuNi-CuNi wiring can have additional break-out at 4K flange to make installation of customer devices possible.

Note: Requires DC installation set

Flexible Grapho coaxial wire

Our flexible coaxial wire assemblies works well up to few GHz and they come with a graphite coating on the insulator to help reduce the effects from microphonic noise. The assemblies are thermalized at each thermal stage in the system by a combination of attenuators and F/F bulkhead feedthroughs mounted in our RF installation set. The wires come with SMA male connectors.

Material of the conductors:

• Inner: SCuNi (Ag plated)
• Outer: CuNi

Characteristic impedance: 50 Ohm
Attenuation (RT): 5.4 dB|m (1.0 GHz)
Attenuation (4K): 4.3 dB|m (1.0 GHz)

Note: Requires RF installation set

Semi-rigid coaxial wires for high frequencies

We have a wide variety of semi-rigid coaxial wires suitable for high frequency measurements. The Semi-rigid coaxial assemblies are thermalized at each thermal stage in the system by a combination of attenuators and F/F bulkhead feedthroughs mounted in our RF installation set. The semi-rigid coaxial cables are available with male SMA (18 GHz) and male K/2.92mm (40 GHz) connectors.

Standard semi-rigid coaxial wires:

SMA (18 GHz): Room temperature (RT) – 4K

• 2.19 mm SCuNi-CuNi (attenuated)
Inner conductor: SCuNi (Ag plated)
Outer conductor: CuNi
Characteristic impedance: 50 Ohm
Attenuation (RT): 1.2 dB|m (1.0 GHz); 3.8 dB|m (10 GHz)
Attenuation (4K): 0.6 dB|m (1.0 GHz); 1.8 dB|m (10 GHz)
• 0.86 mm SCuNi-CuNi (attenuated)
Inner conductor: SCuNi (Ag plated)
Outer conductor: CuNi
Characteristic impedance: 50 Ohm
Attenuation (RT): 3.0 dB|m (1.0 GHz); 9.5 dB|m (10 GHz)
Attenuation (4K): 1.5 dB|m (1.0 GHz); 4.6 dB|m (10 GHz)

SMA (18 GHz): 4K – MXC

• 0.86 mm SCuNi-CuNi (attenuated)
Inner conductor: SCuNi (Ag plated)
Outer conductor: CuNi
Characteristic impedance: 50 Ohm
Attenuation (RT): 1.2 dB|m (1.0 GHz); 3.8 dB|m (10 GHz)
Attenuation (4K): 0.6 dB|m (1.0 GHz); 1.8 dB|m (10 GHz)

0.86 mm NbTi-NbTi (none-attenuated)

Inner conductor: NbTi
Outer conductor: NbTi
Characteristic impedance: 50 Ohm
Attenuation (RT): 9.0 dB|m (1.0 GHz); 30.5 dB|m (10 GHz)
Attenuation (4K): <0.5 dB|m from DC up to 20 GHz

CRYO attenuators will be installed at the 50K, 4K, Still, Cold Plate and mixing chamber stages (except for NbTi lines). The bulkheads will provide mechanical support and will thermalize the outer conductor of the coax lines. However, the PTFE dielectric prevents a good thermal contact to the inner conductor. Therefore, it is recommended to use attenuators directly screwed on the bulkheads in order to also thermalize the inner conductor.

Note: Available CRYO attenuator values: 0, 1, 3, 6, 10 and 20 dB (2 W).

Technical Requirements

Thermocoax and Continuos CuNi-CuNi coaxial assemblies are installed into the KF40 ports with a DC installation set.

Flexible Grapho and semi-rigid coaxial assemblies require RF installation sets. It is important to note that the holes in all of these flanges (including the vacuum flange) are keyed, which will prevent the bulkheads from rotating and getting loose. These thermalization flanges are then screwed onto the experimental flanges of the cryostat, resulting in rigidly mounted bulkheads that serve as mechanical anchors for the coax lines.

Required free ports for DC or RF installation sets

SD

Free KF25 port (1 line) or KF40 port (1–7 lines) for installation.

LD

Free KF40 port (1–7 lines) or KF63 port (1–21 lines) for installation.

XLD

Free KF40 port (1–7 lines) or ISO100 port (1–37 lines) for installation.

XLD1000ep

Free ISO100 port (1-55 lines) for installation

XLDsl

Free Sideloading port (1-25 lines) for installation

Contact our sales team for questions and requests.

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