Bluefors high-density wiring 2020

XLD Dilution Refrigerator System

The XLD Systems are for the most demanding experiments that require large experimental space and superior performance of the cryogen-free dilution refrigerator measurement system. They can accommodate up to 1008 factory-installed semi-rigid 18 GHz coaxial lines in a configuration with two pulse tubes. A single push of a button initiates a fully automated cool-down sequence from room to base temperature.

Six LOS Access Ports

All line-of-sight ports reach from room temperature to mixing chamber.

  • 6 x K100.

Vast Experimental Space

MXC Flange Diameter: 500 mm | 20″

Off-center placed dilution unit maximizes useful space on all flanges. Open design permits easy experimental access without being obscured by heat exchangers or system support structure.

Superior Performance

  • Base temperature well below 10 mK
  • Cooling power: at least 14 µW at 20 mK on the experimental flange with only 18 litres of helium-3
  • Extremely fast cool-down: < 24 hours to 10 mK.

Temperature Controller

The Bluefors Temperature Controller enhance the user experience of our cryogenic systems. With a modern and intuitive user interface, you gain direct control and overview of the system’s temperature status.

The Bluefors Temperature Controller is fully-integrated to all dilution refrigerator measurement systems.

Read more about the Temperature Controller here.

Low Total Cost of Ownership

Oil-free pumps and compressors in gas handling unit guarantee minimal maintenance requirements with service interval up to 3 years. The systems employ only high quality components such as Pfeiffer Vacuum pumps and pressure sensors, VAT vacuum valves and bellows.

Alternative Configuration


The XLDsl (XLD side-loader) dilution refrigerator measurement system is delivered with six side-loading installation sets which for example can fit up to 25 SMA lines each. The side-loading feature allows the assembly work of wiring onto the installation set flanges to be performed away from the cryostat on a work bench. Consequently, the preparation of a wiring assembly or a full experiment can be performed while the system is running. When the system is warmed up to room temperature, the assembly can be immediately exchanged, greatly reducing the room temperature idle time. Preparing and exchanging the installation set assembly is done utilizing a dedicated installation tool that provides the mechanical stability and correct spacing of the flanges when the assembly is not mounted into the cryostat.

High-density wiring is a modular option for the cryogen-free XLDsl dilution refrigerator measurement system that enables a large scale-up of the experimental wiring, especially for high-frequency signals. Read more about the high-density wiring here.


Vibration Isolation

We offer an improved vibration isolation for experiments that are particularly sensitive to low frequency vibrations (< 1 kHz).

  • Basic vibration isolation frame
  • Active vibration damping
  • GHS isolation frame.

Optical Ports

We offer direct optical access to the sample space. The optical ports can be equipped with different window materials and are available in different sizes and configurations. With four 0.5″ optical ports, equipped with our standard fused silica windows, our DR systems still reach a base temperature of <15 mK.

Additional Radiation Shields

We offer the possibility for additional EM shielding around the sample space. These shields can be attached to the mixing chamber plate (LD and XLD) and the cold plate (XLD). Standard shields are made from gold-plated copper. Other materials and platings are available upon request.

Long-Life Cold Trap

We have developed a unique long-life cold trap that allows for continuous operation of the system for up to three years. The trap is integrated with the system and does not need any cryogenic liquids to operate (care-free).

4K Heater Kit

Fully automated fast warm-up option, which allows a day-long warm-up for a standard XLD system.

LN2 Pre-cooling Loop

Engaging LN2 pre-cooling loop with an external source of liquid nitrogen allows to reduce the cool-down time by ~ 40% in case of a basic system.

Extractable 4K Plate

The extractable X4K plate is an option for our XLD size dilution refrigerator measurement systems, and it is located between the 50K and 4K flanges. It is designed for the most demanding measurements where large amount of heat needs to be dissipated at 4K stage without interrupting the performance of the system. The extractable 4K plate is not in thermal contact with the rest of the system so even the large heat loads will not affect the dilution refrigerator measurement system performance. The extractable X4K plate is connected to the 2nd stage of one of the dedicated pulse tube cold heads.

Service Packages and Extended Warranty are available upon request

Technical Specifications

Note: Cooling power is measured on experimental flange outside MXC.

Base temperature10 mK8 mK
Cooling power @ 20 mKat least 14 μW16 μW
Cooling power @ 100 mK400 μW450 μW
Cooling power @ 120 mK575 μW650 μW
Cool-down time to base24 hrs22 hrs
Base temperature10 mK8 mK
Cooling power @ 20 mK30 μW34 μW
Cooling power @ 100 mK1000 μW1100 μW
Cooling power @ 120 mK1400 μW1600 μW
Cool-down time to base24 hrs22 hrs

Performance Graphs


Start cool-down


Start pulse pre-cooling


Stop pulse pre-cooling


Start mixture condensation


Stop mixture condensation


Normal circulation mode

Above are cool-down curves for two different configurations of XLD systems measured with calibrated resistance thermometers.

System 1: basic XLD with 75 coaxial lines and 144 DC lines.
System 2: XLD with 200 mm extra space, MXC shield and additional sample mounting plate.

Pulse pre-cooling sequence (see spots 2 and 3) is one of the key points in reducing the cool-down time. Because we do not use exchange gas some parts of the DR unit stay ‘hot’ on cool down, which prevents condensation of the mixture. By repeatedly admitting the mixture from the tanks through the low impedance still side of the DR and then pumping it out again, these hot spots are effectively cooled down.

Typical Layout

Each Bluefors system is designed to be installed to a specific location defined in advance. A separate layout drawing is made for each Bluefors system, which should always be referred to for exact dimensions.

Bluefors dilution refrigerator LAYOUT XLD STANDARD 2PT 2019

The standard Bluefors XLD can accommodate over 200 factory installed semi-rigid RF coaxial lines still reaching base temperature of ∼10 mK.


A separate layout drawing is made for each Bluefors system, which should always be referred to for exact dimensions.


Single push of a button initiated fully automated cool-down sequence from room to base temperature in a Bluefors dilution refrigerator system.

Technical Requirements

The basic requirements are 3-phase electricity, cooling water, compressed air. The full list of requirements and specification details can be found in the Pre-Installation Guide, please contact our sales team for a copy.

Contact our sales team for questions, requests and Pre-Installation Guide.