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LD

Dilution Refrigerator Measurement System

The LD System is our most sold dilution refrigerator measurement system. Its versatility makes it suitable for many different experimental needs.

Highlights
Technical Specifications
Pulse Tube
Options
Performance Graphs
Layout and Facility Requirements
Contact Sales

The LD System has the largest amount of available options and different magnet configurations that allow it to be customized for different experiments and uses.

The LD400 system typically provides more than 15 μW at 20 mK on the experimental flange with only 18 liters of helium-3. In addition, it has a high cooling power of ∼ 0.5 mW when operated at 100 mK.

This well-engineered dilution refrigerator measurement system has a clean and open design for installing measurement equipment. A single push of a button initiates a fully automated cooldown sequence from room to base temperature.

Product Highlights

1.0

LD

Dilution Refrigerator Measurement System

Fully Automated Operation

Push-button, fully automated cooldown sequence from room to base temperature.

Extensive Capabilities for Experimental Wiring

The system features a variety of access ports for experimental wiring between the Room Temperature and the Mixing Chamber Flange.

  • 2 x ISO-K63 slotted in all flanges
  • 5 x KF40 including central port

Large Experimental Space

Mixing Chamber Flange Diameter: 294 mm | 11.42″

The off-center placement of the dilution unit maximizes useful space on all flanges. An open design permits easy experiment access without heat exchangers or the system support structure getting in the way.

Superior Performance

  • Base temperature below 10 mK
  • Fast cooldown: < 24 hours to 10 mK (measured on an empty system with standard sample space and shield set).
  • Cooling power: >400 µW at 100 mK

See all technical specifications

Temperature Controller

The Bluefors Temperature Controller enhances 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

Low Total Cost of Ownership

The oil-free pumps and compressors in the Gas Handling System guarantee minimal maintenance requirements with a service interval of up to 3 years. The systems contain only high-quality components such as Pfeiffer Vacuum pumps and pressure sensors, VAT vacuum valves and bellows.

Gas Handling System & Control Software Generation 2

Services

Total System Care

Total System Care enables you to focus on your own work – doing research and measurements. The service ensures that systems operate at the best possible performance level and with maximal uptime, without users needing to spend time maintaining the systems themselves.

Learn more

Technical Specifications

2.0

LD

Dilution Refrigerator Measurement System

Note: Cooling power is measured from experimental flange outside the Mixing Chamber. Cooldown time to base temperature is measured from an empty system with standard sample space and shield set.

LD400GuaranteedExpected
Base temperature 10 mK8 mK
Cooling power at 20 mK14 μW16 μW
Cooling power at 100 mK400 μW500 μW
Cooling power at 120 mK575 μW650 μW
MXC Flange Diameter294 mm
Cooldown time to base
temperature		24 h22 h

LD250GuaranteedExpected
Base temperature 10 mK8 mK
Cooling power at 20 mK12 μW14 μW
Cooling power at 100 mK250 μW300 μW
Cooling power at 120 mK360 μW400 μW
MXC Flange Diameter294 mm
Cooldown time to base
temperature		24 h22 h

Pulse Tube Cryocooler Configurations

3.0

LD

Dilution Refrigerator Measurement System

Cryomech Pulse Tube Cryocoolers with remote motors provide cryogenic cooling power to the dilution refrigerator measurement system without the need for liquid cryogens. The cooldown time of the system partly depends on the selected pulse tube power.

There are three pulse tube models available for the LD System: PT415-RM (default), PT420-RM, and PT425-RM. The upgraded Pulse Tube models provide increased cooling power at the 4K Flange.

New: PT310-RM configuration is now available. PT310-RM configuration provides 20% increase in MXC Flange cooling power. Learn more here.

Options

4.0

LD

Dilution Refrigerator Measurement System

Faster turnaround options

4K Heater

4K Heater

The 4K Heater is a fully automated fast warm-up option, which decreases the warm-up time for our cryogenic measurement systems.
Fast Sample Exchange System

Fast Sample Exchange System

The Fast Sample Exchange (FSE) System is a fully automatic load-lock system for fast sample loading and unloading.
LN2 Pre-Cooling Loop

LN2 Pre-Cooling Loop

The Liquid Nitrogen (LN2) Pre-Cooling Loop can be pre-installed in our systems at the factory to achieve faster cooldown.
Still Heat Pipe

Still Heat Pipe

The Still Heat Pipe is a passive component that reduces cooldown time by 10-15%, and improves turnaround time.

Frame Options

Additional Vibration Isolation

Additional Vibration Isolation

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

Sound Isolation

Improved sound isolation for systems situated in spaces that require quieter work environments.

Shield options

Additional Radiation Shields

Additional Radiation Shields

We offer the possibility for additional electromagnetic shielding around the sample space.
Magnetic Shielding

Magnetic Shielding

Magnetic shielding provides protection for samples from interference caused by magnetic fields.

Gas Handling System options

Industrial PC

Industrial PC

The high-performance industrial PC offers fully independent and versatile operation of the Bluefors dilution refrigerator measurement system.
Instrument Cart

Instrument Cart

The Instrument Cart can house supplementary equipment such as temperature controllers, power supplies, and rack-mounted electronics.
Redundant Main Circulation Unit

Redundant Main Circulation Unit

For added security, we offer a Redundant Main Circulation Unit to secure operation in atypical circumstances
Service Booster

Service Booster

The Service Booster is a dedicated turbomolecular pump for vacuum pumping, enabling more secure operation of the system.

Other options

Additional Sensors

Additional Sensors

Additional temperature sensors can be integrated into the system for comprehensive diagnostics and measurements.
Helium Battery

Helium Battery

The Helium Battery makes it possible to run experiments at mK temperatures for a limited time with the pulse tube cryocooler turned off.
Long-Life Cold Trap

Long-Life Cold Trap

The Long-Life Cold Trap enables the continuous operation of the system for up to three years.
Optical Access Ports

Optical Access Ports

Optical Access Ports offer direct line-of-sight access to the sample space.

Performance Graphs

5.0

LD

Dilution Refrigerator Measurement System

1Start cooldown
6Normal circulation mode
5Stop mixture condensation
4Start mixture condensation
3Stop pulse pre-cooling
2Start pulse pre-cooling

Above are cooldown curves for three different configurations of LD systems measured with calibrated resistance thermometers.

  • System 1: basic LD with LN2 pre-cool
  • System 2: basic LD
  • System 3: LD with 100 mm extra sample space, Mixing Chamber shield, additional sample mounting plate, and large amount of DC and RF cabling.

The Pulse Pre-Cooling sequence is one of the key points in reducing the cooldown time (see spots 2 and 3). Because we do not use exchange gas, some parts of the dilution refrigerator unit stay ‘hot’ on cool down, which prevents condensation of the helium3 –helium-4 mixture. To cool down these hot spots effectively, the mixture is repeatedly admitted from the tanks to the Still side of the dilution refrigerator to operate as an exchange gas and then pumped out again.

Services

Customer Care

We support our customers throughout the lifetime of their system, providing dedicated care to find solutions for any issues. Our technicians and engineers are ready to help you wherever you are located, with prompt service delivered either remotely or on-site.

Learn more

Layout and Facility Requirements

6.0

LD

Dilution Refrigerator Measurement System

Layout Overview

Bluefors LD System layout overview
1. Cryostat and its support frame, 2. Thermometry Unit, 3. Gas Handling System, 4. Pulse Tube Cryocooler compressor.

Each of our systems 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.

Facility Requirements

The basic requirements are 3-phase electricity, cooling water, and 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.

LD Systems Empowering Research

See Also

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Contact form – choose your product or service interest:

Bluefors Systems
Options for an existing Bluefors System
Cryomech Systems
Accessories for an existing Cryomech System
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