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Differences Between Pulse Tube and Gifford-McMahon Cryocoolers

Writers

Business Analyst Nathan Kellar
Nathan Kellar
Business Analyst
Cryogenic R&D Engineer Dr. Xihuan Hao
Dr. Xihuan Hao
Cryogenic R&D Engineer

Cryocoolers are specialized devices designed to provide cooling at extremely low temperatures, reaching cryogenic levels. These sophisticated systems are used across a multitude of fields, from scientific research to industrial applications, where maintaining low temperatures is essential. Whether, enhancing the performance of infrared sensors, or ensuring the efficiency of superconducting devices, cryocoolers play an indispensable role.

Although different in their design and purpose, both Pulse Tube (PT) and Gifford-McMahon (GM) cryocoolers have become essential in the cryogenics industry. They each have their own benefits and specialized uses. Gifford-McMahon cryocoolers are known for their efficiency and robustness and have been a vital component in cryogenics for decades, offering steady and consistent cooling for a variety of applications. Pulse Tube cryocoolers are a newer technology, and with fewer moving parts, provide unique advantages such as reduced vibration and lower maintenance requirements.

Despite their differences, both types of cryocoolers play key roles in the cryogenics industry. Understanding their unique advantages helps in selecting the appropriate technology for specific applications.

How Cryocoolers Operate

Cryocoolers operate on the principle of thermodynamic cycles, specifically designed to achieve and maintain extremely low temperatures. These systems typically consist of a cold head, compressor, and heat exchanger, each playing a vital role in the cooling process.

By utilizing different mechanisms, they effectively transfer heat from the target area to the cooler environment. This precise control of temperature is crucial in applications where even minor thermal fluctuations can impact performance and results.

Gifford-McMahon cryocoolers operate through a mechanical displacer moving inside the cold head. These cryocoolers are known for their effectiveness in achieving and maintaining extremely low temperatures, making them a preferred choice for many industrial and scientific applications – however the movement of the displacer causes more vibrations, making them less suitable for vibration-sensitive applications.

Gifford-McMahon Cryocooler operating principle diagram
Operating principle of a Gifford-McMahon Cryocooler.

Pulse Tube cryocoolers represent a more advanced technology that eliminates the need for moving mechanical parts in the cold head. Instead, PT cryocoolers rely on oscillating pressure to transfer heat, resulting in reduced vibrations and more precise results. This innovative design not only enhances the longevity of the system but also minimizes potential disruptions in sensitive applications.

Pulse Tube Cryocooler operating principle diagram
Operating principle of a Pulse Tube Cryocooler.

Key Differences Between PT and GM Cryocoolers

When comparing PT and GM cryocoolers, several key factors stand out, including temperature, efficiency, vibration levels, orientation sensitivity, maintenance, and price.

Temperature

In the Bluefors product range, Gifford-McMahon cryocoolers are highly effective in achieving and maintaining temperatures between 12 K and 80 K. In contrast, our Pulse Tube cryocoolers, provide more precise temperature control in the range of 3 K to 80 K, and are ideal for applications sensitive to even minor thermal fluctuations.

Efficiency

In terms of efficiency, Pulse Tube cryocoolers generally offer more precise results and a longer operational life due to the reduced number of mechanical components. However, Gifford-McMahon cryocoolers can provide higher efficiencies, making them suitable for applications requiring significant cooling power.

Vibration levels

Again, with fewer mechanical components, Pulse Tube cryocoolers are inherently less prone to vibration caused by any moving parts, making PT cryocoolers the preferred choice for vibration-sensitive applications.

Orientation sensitivity

When it comes to orientation, there’s a notable difference between Pulse Tube (PT) and Gifford-McMahon (GM) cryocoolers, largely due to their design and operational requirements. PT cryocoolers (with the notable exception of the PT425 and PT450) typically operate in a vertical position as any deviation can introduce inefficiencies. In contrast, GM cryocoolers are more versatile; they can function in almost any orientation. This flexibility makes GM cryocoolers ideal for installations where vertical alignment may not be optimal.

Price and Maintenance

Regarding cost, Pulse Tube cryocoolers often come with a higher initial cost but lower long-term operating costs, whereas Gifford-McMahon cryocoolers tend to be more affordable upfront, but may incur higher maintenance costs over time.

Cryomech Pulse Tube Cryocoolers
Pulse Tube Cryocoolers with different configurations.

Industrial Applications for Pulse Tube and Gifford-McMahon Cryocoolers

PT and GM cryocoolers serve diverse roles across a spectrum of industries, each leveraging the specific strengths of the cryocooler to meet the desired cooling requirements. Pulse Tube cryocoolers, are critical in applications requiring stable and reliable cooling, such as quantum technology. It is for this reason that they are an integral part of all Bluefors Dilution Refrigerators.

Pulse Tube cryocoolers are also essential components in astronomical technologies, such as space telescopes, where they are used to cool infrared sensors. Another field where PT cryocoolers play an instrumental role is in materials science research, where any vibrations might negatively impact results.

Gifford-McMahon cryocoolers, with their robust design and versatility, are indispensable in R&D settings, supporting experiments in physics and materials science at extremely low and precise temperatures. They are also vital in industrial processes such as semiconductor manufacturing, where consistent cooling is essential.

GM cryocoolers are also commonly utilized in high-energy applications such as particle accelerators and medical imaging technology, such as MRI scanners.

Together, Pulse Tube and Gifford-McMahon cryocoolers provide essential solutions across a wide array of industries, ensuring reliable and efficient performance, regardless of the environment.

AL630 Gifford-McMahon Cryocooler
AL630 Gifford-McMahon Cryocooler

The Future of Cryocoolers

Looking ahead, growing industrial demands and new applications signal a future of innovation for PT and GM cryocoolers, leading to improvements in efficiency and cooling capacity, as well as the development of even more compact and lightweight designs.

These advancements will potentially expand their use in space exploration, medical imaging, as well as wider use in fields where they already play an important role, such as quantum computing. As industries continue to push the boundaries of low-temperature applications, both types of cryocoolers will play crucial roles in the continued growth of different industries and fields of research.

Pulse Tube Cryocoolers (PT)Gifford-McMahon Cryocoolers (GM)
Operating Temperature Range3 – 80 K12 – 80 K
Initial CostHigherMore Affordable
Potential Long-term Operating CostsLowerHigher
MaintenanceMinimalMay incur higher maintenance costs over time
ApplicationsQuantum technology, space telescopes, materials science researchR&D settings, semiconductor manufacturing, high-energy applications, medical imaging
Vibration ImpactReduced vibrations, ideal for sensitive applicationsRobust design, versatile but higher vibrations
Cooling PowerStable and reliable coolingSignificant cooling power and efficiency
Table of key differences between Pulse Tube Cryocoolers and Gifford-.McMahon Cryocoolers.

Unique Advantages of Cryocoolers

Both Pulse Tube and Gifford-McMahon cryocoolers offer unique advantages tailored to specific cryogenic requirements. GM cryocoolers, with their robust design and high cooling capacity, remain indispensable in applications demanding significant cooling power and efficiency. Conversely, PT cryocoolers, with their reduced vibrations and minimal maintenance, are ideal for sensitive and precise applications.

As technological advancements continue to push the boundaries of cryogenic applications, both Gifford-McMahon (GM) and Pulse Tube (PT) cryocoolers will remain a staple across a wide range of industries. Read more about our complete range of Cryomech Pulse Tube Cryocoolers and Gifford-McMahon Cryocoolers, or contact our sales engineers for further assistance finding the right cryocooler for your specific needs.