Les nouveautés chez Sunpower inc

Sunpower Inc. Announces Availability of CryoTel® DS30 Cryocooler Engineering Build Units

Sunpower, Inc., the world leader in free-piston Stirling engine and cryocooler technology, announces the development of the DS30 cryocooler as well as the ability for select customers to purchase a DS30 Engineering Build (EB) unit.

The CryoTel® DS 30 Stirling cryocooler offers efficient, reliable, compact and high power cooling to the market in the temperature range of 35 to 250 Kelvin. The DS30 was optimized for applications in which SWAP (size, weight and power) and reliability are concerns. The DS30 consumes considerably less power than other cooling alternatives and requires no maintenance, making it ideal for strategic as well as industrial applications. Both the cold head and the pressure wave generator can be mounted in any orientation. Application examples include semiconductor manufacturing,  large infrared detectors, RF receivers or antennas, astronomical telescopes, laser cooling, high-temperature superconductivity, cold traps, and others.


Les nouveautés chez JANIS

Cryocooler System with Recirculating Helium Gas

Cryocooler System with Recirculating Helium Gas Cools Continuous Transfer Type Cryostats

The ongoing global helium shortage continues to adversely affect researchers, many of whom are unable to use
these their existing continuous transfer cryostats to perform research due to high operating costs or limited LHe availability.
Janis Research is now offering a solution to help researchers that have limited operating budgets but that can gain access
to capital equipment funding.
Janis Research has developed a series of cryogen free, low vibration, closed cycled cryocooler systems that use
recirculating helium gas as a direct replacement for liquid helium, to cool continuous flow cryostats without
the use of LHe. Pulse tube-cooled (PT) and Gifford-McMahon (G-M) cryocooler options are available, in various capacities
and base temperature configurations. Helium gas passes through a series of heat exchangers on the cryocooler, and then
flows through the integrated vacuum insulated transfer line into the cryostat. After cooling the sample, the gas is then returned to
the cryocooler for re-cooling and continued circulation.

These recirculating gas cryocooler systems are available for use with almost any existing continuous transfer type cryostats,
such as the Janis SuperTran series. The Model PT-7 pulse tube-cooled system shown below operates continuously with a
base temperature of less than 7 K (with options for lower temperatures). The interchangeable system transfer line tips make
the cryogen free cryostat universal for all Janis SuperTran cryostats including Models ST-100, ST-300, ST-400 and ST-500.
The microscopy cryostat system as shown can, with proper mounting, maintain the vibration level on the cryostat body
at less than 20 nm.

 

 

 

 

 

Cryogen Free sub-Kelvin ARPES System

 

 

 

Introduction

 

Angle-Resolved Photoemission Spectroscopy (ARPES) is used to study the electronic structure of the surface of solids. The ARPES technique employs a synchrotron or laser beam to interact with a sample, resulting in emission of photoelectrons. By analyzing the energy and momentum of the photoelectrons, the Fermi surface of the material can be mapped. ARPES experiments are often performed in the 2 Kelvin – 10 Kelvin range, but recent research trends often require temperatures below 1 Kelvin (sub-K).

 

 

 

Janis Research delivered the world’s first continuous operating high cooling power “wet” He-3 ARPES cryostat in 2008, achieving a base temperature of 0.9 K. (https://www.tandfonline.com/doi/abs/10.1080/08940886.2012.720159) Similar systems have since been installed at leading research facilities around the world, but the recent global helium shortage has made continuous operation of these large sub-K ARPES systems costly. In response to researcher demand, Janis Research has successfully developed another world first, a continuously operating high cooling power cryogen-free (“dry”) sub-K cryostat for ARPES. This dry He-3 system eliminates the need (and cost) of liquid helium, while also simplifying the design and dramatically reducing the cryostat size.

 

 

 

 

 

 

 

 

 

Cryostat design

 

The Janis Research dry sub-K ARPES cryostat is designed and fabricated for true UHV operation, and can be baked to 90C. A two-stage pulse tube refrigerator (PTR) cools two internal platforms and thermal shields to 35 K (first stage) and 3 K (second stage.) The PTR is mounted by metal sealed CF flange to a z-motion linear translation stage. The PTR is raised and detached from the cryostat during vacuum baking, then lowered into position for normal operation. Heat exchangers mounted to the PTR and platforms precool two independent closed loops of recirculating He-4 and He-3 gas. Two separate He-3 condensers can be used to transform the He-3 gas into liquid; the choice of condenser depends upon experimental requirements and is made by valve adjustment. A He-3 pot is used to collect the condensed liquid, and tapped holes in the He-3 pot are used for sample mounting. Precisely aligned slots in the thermal shields allow the synchrotron radiation or laser to reach the sample. Movable shutters are also installed on the thermal shields and are mechanically linked together. Both shutters can be opened simultaneously for sample mounting and removal using a wobble stick, and then closed to improve thermal performance. A multifunction mechanical heat switch is used to precool the system, and to operate the system in variable temperature (He-4) mode. A large capacity gas sealed roots pump is used to circulate the He-3 gas.

 

 

 

Sliding sample access shutter

 

 

 

Operating principal

 

The system can be operated in three distinct modes.

 

 

 

He-4 Mode: In this mode, only He-4 gas is circulated; He-3 circulation is not required. After being precooled through the heat exchangers, He-4 gas is condensed through an impedance and enters a 1 K pot. Pumping on the He-4 gas results in a base temperature of ~1.3 K. The mechanical heat switch is configured to provide a direct thermal link between the 1K pot and the He-3 pot, resulting in variable temperature operation in the range of ~4 K – 320 K. This operating mode is especially user friendly, and offers fast thermal cycling of samples over a wide temperature range.

 

 

 

1 K operation mode: In this mode, the mechanical heat switch is opened. External valves are configured to direct the circulating He-3 gas through a heat exchanger inside the 1 K pot. The He-3 gas is precooled and then condensed after expansion through an impedance, collecting inside the He-3 pot and cooling it to 500 mK.

 

 

 

JT operation mode: In this mode, the mechanical heat switch is opened, and the external valves are configured to direct the circulating He-3 gas to the JTCU. The incoming gas is precooled to ~2 K by the He-3 exhaust stream and then condensed by expansion through an impedance, cooling the He-3 pot to 550 mK.

 

 

 

Summary

 

The Janis Research dry sub-K cryostat for ARPES is a convenient multi-functional tool, suitable for a wide range of research applications. The system offers researchers the means to achieve sub-K temperatures in ARPES configuration, temperatures as low as 300 mK with beam slits closed, as well as high cooling power and unlimited experimental duration.

 

 

 

 

 

Contact: Cryoforumis.com

 

Web: https://www.janis.com/Dry_Sub-K_ARPES_System.aspx

 


Les nouveautés chez SHI Cryogenics Group

SHI Cryogenics Group Releases Highest Capacity 4K Cryocooler to Date


RDE-418D4 4K Cryocooler

New RDE-418D4 Cryocooler Increases Cooling Performance by 20% Compared to Existing Models

ALLENTOWN, PA, January 3, 2019 – The SHI Cryogenics Group has added a new model to its line of Gifford-McMahon (GM) Cryocoolers with the introduction of the RDE-418D4 1.8/2.0W 4K Cryocooler. The RDE-418D4 is SHI’s highest-capacity 4K Cryocooler to date, and extends the company’s existing range of 0.1W to 1.5W models. SHI’s 4K GM Cryocoolers are recognized as the most reliable and versatile systems available in the marketplace, featuring high cooling capacities, compact designs and orientation-free operation.

Compared to SHI’s RDK-415D 1.5W 4K Cryocooler, the RDE-418D4 features an optimized design that increases cooling performance by 20% without increasing the cryocooler’s physical size or the compressor’s input power. The new cryocooler has a first stage capacity of 42/50W at 50K (50/60Hz), and a second stage capacity of 1.8/2.0W at 4.2K (50/60Hz). The RDE-418D4 also features the same interface design as the RDK-415D, easing the ability to swap the new cryocooler into existing cryostat designs.

In addition to the cryocooler, the complete system includes a helium compressor, gas lines and power cables. It is CE and UL certified, with a suggested maintenance interval of 10,000 hours. The F-50 compressor is a three-phase, indoor, water-cooled unit that is available in both high and low voltage models. All Freedom® series compressors utilize highly-reliable scroll compressor capsules, have an industry-leading 30,000 hour maintenance interval, and are designed exclusively to deliver high pressure, oil-free helium to cryogenic refrigerators.

Like all SHI cryocoolers, the RDE-418D4 is competitively priced, and provides a stable low-temperature solution for a variety of research purposes, including helium liquefaction, superconducting magnets and detector cooling. The SHI Cryogenics Group has the largest installed base of cryocoolers around the world, and supports its customers with a global service and support network of twelve offices and numerous representatives.