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Topic: Cryocooler

In the News (Fri 1 Jun 12)

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	Cryocooler Contamination (Cryogenics Refrigerators, Coolers, Engines)
		Due to the lack of outgassing data as a function of temperature, a linear function was adopted, assuming desorption of gases from a monolayer.
		Care must be taken in applying values in Table 1 for Equation 2, for the contamination level inside a cooler is a function of the amount of gas in the cooler.
		"Cryocooler Contamination Study: Temperature Dependence of Outgassing", to be published in the proc.
	www.yutopian.com /Yuan/CContam.html (589 words)

	Efficient thermal joints for connecting current leads to a cryocooler - Patent 4876413
		The cooling stations of the cryocooler can be used to remove heat from the leads but the leads have to be electrically isolated from the cryocooler and one another while still having a sufficiently high thermal conductivity so that heat transferred down the leads can be intercepted before it reaches the magnet.
		A flange 67 on cryocooler 71 is secured to the second flange 63 with the cold end of the cryocooler including the two cooling stages 73 and 75 extending into the inner sleeve 15.
		Heat transfer between the second stage cryocooler heat station and the shield 23 directly surrounding the winding form having magnet windings 101 is accomplished by copper cylinder 21a being directly bolted to the copper shield 23.
	www.freepatentsonline.com /4876413.html (2975 words)

	Cryogenic Society of America - Cryo Central - Cryocoolers (Site not responding. Last check: 2007-10-20)
		One application for relatively compact cryocoolers that are able to reach 4.2K with a heat lift between 0.1W and 1W relates to integrating such cryocoolers with superconducting electronics A family of instrumentation products comprises the initial set, followed by possible military communications and electronic hardware, and finally commercial communications hardware.
		Reliable cryocoolers are the enabling technology, and size will vary with the deployment platform, from very compact in the case of airborne systems to acceptably large (1 or 2 Watts at 4.2K) for ground-based installations.
		Cryocoolers of very long lifetime (maintenance-free is highly desired) are indispensable in this case and are the main gating factor for the explosion of such a market.
	www.cryogenicsociety.org /cryo_central/cryocoolers.php (4447 words)

	Multi-stage pulse tube cryocooler patent invention
		A three-stage pulse-tube cryocooler, in which the third stage pulse tube is arranged below the second stage pulse tube, with a gas flow conduit between the second stage pulse tube heat exchanger and the cold end of the second stage regenerator.
		The cooler shown in figure (c) is an attempt by the inventor to increase efficiency in the second stage by adding a gas bypass orifice between the second stage pulse tube and the second stage regenerator to control phasing of gas flow within the second stage.
		[0013] Three-stage cryocoolers are also known in the prior art which include all of the parts of a two-stage pulse tube cryocooler, plus a third reservoir, a third-stage regenerator, and a separate third-stage pulse tube in parallel with the first- and second-stage tubes.
	www.freshpatents.com /Multi-stage-pulse-tube-cryocooler-dt20051215ptan20050274124.php (1218 words)

	Development of a fluorescent cryocooler
		The remaining mass of the cryocooler is composed of the outer wall, diode lasers, heat sinks, and control electronics.
		By integrating the cryocooler into the overall spacecraft design, a cryocooler system might be constructed with a mass as small as several hundred grams.
		A cryocooler for use in space applications requires a radiation source that is compact, efficient, reliable, and rugged and has the necessary power and wavelength.
	www.usna.edu /Users/physics/mungan/Publications/AIAA.html (3162 words)

	NIST miniature refrigerator flies aboard current shuttle mission
		Cryocoolers can be used to cool infrared sensors needed for the study of temperature variations in the atmosphere and the oceans.
		The primary objective for flying the cryocooler in space is to determine its performance in a microgravity environment.
		A test of the cryocooler aboard a 1998 shuttle flight was inconclusive because of onboard battery problems.
	www.eurekalert.org /pub_releases/2001-12/nios-nmr120701.php (259 words)

	Zero-Boil-Off Hydrogen Densification System (Site not responding. Last check: 2007-10-20)
		Since the cold head of the cryocooler is not long enough to reach the bottom of the storage tank, the heat pipe is used.
		The heat pipe is located at the bottom of the cold head and extends the cryocooler cold head to the bottom of the inner vessel.
		Three silicon diode temperature sensors are installed on the cryocooler cold head, upstream and downstream of the heat pipe.
	media.fsec.ucf.edu /2005_transcript (1007 words)

	STRV 1B: EXPERIMENTS
		Cryocoolers are typically used to cool IR or CCD sensors to lower the thermal noise threshold.
		Using the cryocooler as a vibration source, the response of the satellite was determined from accelerometer data.
		Once again, a tactical cryocooler will be used, but in a more demanding role as the primary cooling for an active focal plane array in an infra-red optical system.
	lasp.colorado.edu /strv/exp1b_strv.html (2406 words)

	SWIR
		Cryocooler (Green) - The platinum Silicide-Silicon Schottky barrier linear detector array in each of the six SWIR channels are cooled to 80 K using a mechanical split Stirling cycle cooler of long life and low vibration design.
		Cooling is provided by a split Stirling cycle cryocooler with opposed compressors and an active balancer to compensate for the expander displacer.
		Because the cooler is attached to the SWIR telescope, which must be free to move to provide cross-track pointing, this heat cannot be removed using a platform provided cold plate.
	asterweb.jpl.nasa.gov /swir.asp (395 words)

	Tristan Technologies, Inc./Technotes/Laboratory
		Cryocoolers can be used to reduce boiloff by cooling radiation shields.
		As early as 1980, a 200 liter cryocooled dewar was supplied (not by Tristan Technologies) to GWR Instruments (San Diego, CA) for a superconducting gravimeter.
		One method of decoupling is a thick rubber gasket at the physical interface between the dewar and the mechanical cooler and flexible copper braids for thermal contact rather than a rigid mounting point(s).
	www.tristantech.com /technotes_refriger.html (641 words)

	Acoustic cryocooler (US4953366) (Site not responding. Last check: 2007-10-20)
		An acoustic cryocooler with no moving parts is formed from a thermoacoustic driver (TAD) driving a pulse tube refrigerator (PTR) through a standing wave tube.
		Thermoacoustic elements in the TAD are spaced apart a distance effective to accommodate the increased thermal penetration length arising from the relatively low TAD operating frequency in the range of 15-60 Hz.
		The tube may be coiled to reduce the overall length of the cryocooler.
	www.delphion.com /details?pn=US04953366__ (441 words)

	High-frequency cryocooler is tiny, cold and efficient
		The new cryocooler, described in the current issue of Applied Physics Letters,* is a "pulse tube" design that uses oscillating helium gas to transport heat, achieving very cold temperatures (223 degrees C or -370 degrees F) in a matter of minutes without any cold moving parts.
		The new cryocooler is as efficient as the low-frequency version because it uses a higher average pressure and a finer screen mesh in the regenerator—a stainless steel tube packed with screening that provides a large surface area for transfer of heat between the gas and the steel.
		These applications include cooling infrared sensors in space-based instruments used to measure temperature and composition of the atmosphere and oceans for studies of global warming and weather forecasting, and cooling night-vision sensors for tanks, helicopters, and airplanes.
	www.eurekalert.org /pub_releases/2007-02/nios-hci021507.php (457 words)

	Cryogenic Society of America - Cryo Central - Telecommunications (Site not responding. Last check: 2007-10-20)
		The continuing objective of this workshop is to perform an industry assessment on the current status of low cost, highly reliable cryocoolers and to estimate the current and perceived needs of the cooled electronic communities.
		Development programs are currently underway, with the aim to produce unique receivers and transmitters (transceivers) that have the ability to cover the full available spectrum digitally, thus enabling the holy grail of "software radio," i.e., universal and seamless communications across all varying wireless systems, regardless of the frequency or coding protocols they use.
		Cryocoolers and cryocooling have always been characterized as the key enabling product and technology for superconducting electronics.
	www.cryogenicsociety.org /cryo_central/telecommunications.php (3647 words)

	Creare Engineering Services – NICMOS Cryocooler
		In March 2002, a cryocooler and cryogenic circulator loop that was developed by Creare was installed on the Hubble Space Telescope (HST).
		Within six weeks of its installation on the HST, Creare’s cryocooler had returned the NICMOS detectors to operational temperatures (~75 K), and the first images generated by the renewed device were obtained shortly thereafter.
		The instrument had been cooled by a block of solid nitrogen that had depleted, and a replacement cooling system had to be developed and space qualified in time for the scheduled servicing mission to the HST.
	www.creare.com /services/cryo/nicmos.html (241 words)

	Miniature Long Life Stirling Cryocoolers / Stirling Coolers
		The range of cryocoolers which are the subject of this paper provide an optimum solution for the system designer and user by offering very long life and high reliability within a small package and at a modest cost of acquisition.
		Two cryocoolers from this batch were assigned to long term testing in laboratory conditions.
		As no problem was found the cryocoolers were finally charged and sealed in 1994 and have, at the 24 April 2001, had run for respectively 52463 and 53702 hours with full data logging.
	www.hymatic.co.uk /stirling.cryocooler.design.htm (1684 words)

	current-research
		I am currently developing a miniature cryocooler for remote sensing applications, the cryocooler utilises the Sirling cycle and has a target cold end temperature of 80 Kelvin and a warm end temperature of 200k.
		The linear motor that is used to drive the compressor has been designed to be highly efficient, and was the result of a period of finite element analysis performed in the first year of my research.
		Finite element analysis (using the FEMM program) was used to determine the suitability of various magnet assembles for use in the linear motor and a Mathematica(tm) notebook created to use the output of the finite element program to calculate the efficiency of a motor utilising such designs would have.
	users.ox.ac.uk /~linc1319/current-research.html (506 words)

	AIRS - Technology: Subsystems: Cooler Electronics
		The cryocooler control electronics (see photo) operate off a 28 Vdc spacecraft bus and provide high efficiency, synchronized drive to the compressor pistons.
		The development of the space qualified pulse tube cryocooler was a key accomplishment for the program and represents a major advance in cryogenic technology.
		Both cryocoolers achieved a thermodynamic efficiency (system input power/cooling capacity) of approximately 62 W/W at 55 K operation with a net cooling capacity of 1.5 Watts.
	www-airs.jpl.nasa.gov /Technology/Subsystems/CoolerElectronics (194 words)

	2G Enterprises - Cryo-Manual - 5. Cryocooler Maintenance and Problems
		It is very important to replace the charcoal adsorber in the cryocooler compressor every 1000 hours (once per year).
		A specific problem we have experienced is contamination in the cryocooler system that results in sticking of the displacer in the cold head component of the cryocooler.
		This causes the cold head to heat the cryocooler cylinder and to warm the frozen contaminant so that it is flushed out with the helium purge gas.
	www.2genterprises.com /cryo_manual_5.html (1387 words)

	Independent Science Review: NICMOS Cryocooler
		The Review was asked to consider the implications of mounting a cryocooler on NICMOS during the Third Servicing Mission (SM3), with the aim of prolonging the life of the instrument.
		The Cryocooler Independent Science Review (CC-ISR) was charged with conducting a high-level review of the cooler as soon as possible after the completion of a Critical Design Review that was held at GSFC on September 4 and 5, 1997.
		The ISR was given a presentation on the costs of preparing a Creare cryocooler for a HOST flight aboard the Shuttle and for the SM3 installation of the cryocooler on NICMOS.
	www.stsci.edu /observing/nicmos_cryocooler_isr.html (2597 words)

	TA: Article (Site not responding. Last check: 2007-10-20)
		Mainstream also added adsorption beds to the cryocooler, allowing for stored cooling without power—this application is being marketed as a stand-alone backup cooling unit in hospitals and medical laboratories.
		The single-stage vapor compression cryocooler utilizes a cascaded vapor compression refrigeration cycle with a blend of several refrigerants which have a range of boiling points.
		Mainstream is commercializing its cryocooler technology as a stand-alone backup cooling unit in hospitals and medical laboratories—primarily as a replacement for liquid nitrogen-cooled systems.
	www.mdatechnology.net /printerpage_techsearch.asp?articleid=485 (432 words)

	Carleton Life Support Systems Inc. LC1061 Linear Cryocooler (Lightweight 1 Watt)
		This cryocooler maintains the level of performance of the SADA II 1w cryocooler design, from which it was derived weighing 4.2 lbs.
		Cryocooler durability is not compromised as part of the lightweight design as it has been designed and proven to survive very high vibration environments.
		This cryocooler design typically used on airborne applications that carry multiple IR systems which utilize large format focal plane array’s, such as the Joint Strike Fighter.
	www.carletonls.com /productsbu/lc1061.htm (364 words)

	ABSTRACT
		The centreplate incorporates heat spreading both internally for removing compressor heat as well as for spreading the heat to the radiator to which it can be attached.
		The key feature of the Oxford design philosophy is the holistic approach to design taken – too many cryocoolers have been designed that are almost impossible to assemble.
		Hence the key to quantity production of cryocoolers is the verification (where possible) of each and every stage of the production process, from component manufacture to final assembly.
	www.hymatic.co.uk /stirling.cryocooler.tp1.htm (2311 words)

	SCW sample articles
		Many existing compact cryocoolers, such as numerous devices for infrared sensor applications, are small and efficient—about 7lbs and consuming 12W—but are single stage coolers, and can only achieve temperatures in the range of 30K to 70K.
		To devise the specifications for the tactical cryocooler, HYPRES was assisted by a government advisory panel that included scientists, engineers, and program managers from multiple organizations associated with this, and other, related projects.
		Because the cryocoolers will be part of communications equipment installed in relatively large quantities and in a variety of vehicles and other combat platforms, designs must meet challenging design criteria.
	www.superconductorweek.com /sample_articles.htm (11031 words)

	Report of the Independent Science Review: NICMOS Cryocooler
		On the technical side, the cryocooler system had been successfully flown and tested in space; and great care had been taken to characterize the thermal, mechanical, and electro-optical changes that NICMOS had undergone late in 1998 and during the rapid warm-up of January 1999.
		Reliability of Cryocooler Hardware: Although the NCS had a highly successful test flight on Shuttle mission STS-95, demonstrating the capability of NCS to achieve the temperature levels required for an extended NICMOS mission, there is still concern about the long-term reliability of the system.
		We recommend that the Reverse Brayton-Cycle Cryocooler of the NICMOS Cryocooler System (NCS) be installed on NICMOS on the SM3 servicing mission provided that a number of important concerns listed in sections 6 and 7 are resolved to the satisfaction of the usual technical and flight-readiness reviews prior to flight.
	www.stsci.edu /observing/nicmos_cryocooler_isr1999.html (2598 words)

	Design and Status of the NICMOS Cryocooler
		For example, the Creare cryocooler system within NCS is the leading technology candidate to provide the Next Generation Space Telescope (NGST) with sufficient cooling to support a mid-infrared (thermal) IR instrument.
		The Creare cryocooler is connected to the flex lines cooling loop by means of a heat exchanger operating at 62 Kelvins.
		A cutaway view of the NCC is shown in Figure 2 and the assembled unit (minus its external thermal blankets is shown in Figure 3.
	www.stecf.org /conferences/sardinia/node38.html (2002 words)

	TA: Article (Site not responding. Last check: 2007-10-20)
		AMTI's cryocooler does not use periodic flow regenerators and does not rely on the specific heat of any regenerator packing and therefore, it is capable of being extremely efficient at very low temperatures.
		AMTI's cryocooler is insensitive to dead volume, which is the space, occupied by refrigerants or gas, that is not contributing to the cooling of the system.
		AMTI is seeking a suitable compressor to attach to the cryocooler for space applications.
	www.mdatechnology.net /printerpage_spin.asp?articleid=614 (1124 words)

	NIST's High-Frequency Cryocooler Is Tiny, Cold, Efficient
		The cryocooler can be used to chill instruments for space and military applications, and is a significant step toward even smaller, higher-frequency versions for integrated circuits (ICs) and microelectromechanical (MEM) systems.
		The new cryocooler, described in Applied Physics Letters, is a "pulse tube" design that uses oscillating helium gas to transport heat, achieving very cold temperatures (-223 C or -370 F) in a matter of minutes, without any cold moving parts.
		Experts said the new cryocooler is as efficient as the low-frequency version because it uses a higher average pressure and a finer screen mesh in the regenerator - a stainless steel tube packed with screening that provides a large surface area for transfer of heat between the gas and the steel.
	engineers.ihs.com /news/nist-tiny-cryocooler.htm (636 words)

	ILL : ANNUAL REPORT 2000
		The first one is incorporated into an ILL top-loading cryocooler and therefore, routinely available to the ILL users.
		The Joule-Thomson (JT) stage is added to an APD cryocooler to expand the temperature range down to 1.8 K. A descriptive of the Joule-Thomson stage is shown in Fig.
		For the top-loading cryocooler, the set-up is similar except that the liquid-nitrogen trap is not needed.
	www.ill.fr /AR-00/p-89.htm (637 words)

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