This book is the first in English being entirely dedicated to Miniature Joule-Thomson Cryocooling. The category of Joule-Thomson (JT) cryocoolers takes us back to the roots of cryogenics, in 1895, with figures like Linde and Hampson. The "cold finger" of these cryocoolers is compact, lacks moving parts, and sustains a large heat flux extraction at a steady temperature. Potentially, they cool down unbeatably fast. For example, cooling to below 100 K (minus 173 Celsius) might be accomplished within only a few seconds by liquefying argon. A level of about 120 K can be reached almost instantly with krypton. Indeed, the species of coolant plays a central role dictating the size, the intensity and the level of cryocooling. It is the JT effect that drives these cryocoolers and reflects the deviation of the "real" gas from the ideal gas properties. The nine chapters of the book are arranged in five parts. •The Common Principle of Cyrocoolers shared across the broad variety of cryocooler types •Theoretical Aspects: the JT effect and its inversion, cooling potential of coolants, the liquefaction process, sizing of heat exchangers, level of pressurization, discharge of pressure vessels • Practical Aspects: modes of operation (fast cooldown, continuous, multi-staging, hybrid cryocoolers), pressure sources, configuration, construction and technologies, flow adjustment, MEMS, open and closed cycle, cooldown process and similarity, transient behavior • Mixed Coolant cryocooling: theory, practice and applications • Special Topics: real gas choked flow rates, gas purity, clog formation, optimal fixed orifice, modeling, cryosurgical devices, warming by the inverse JT effect The theoretical aspects may be of interest not only to those working with cryocoolers but also for others with a general interest in "real" gas thermodynamics, such as, for example, the inversion of the JT effect in its differential and integral forms, and the exceptional behavior of the quantum gases. A detailed list of references for each chapter comprises a broad literature survey. It consists of more than 1,200 relevant publications and 450 related patents. The systematically organized content, arranged under a thorough hierarchy of headings, supported by 227 figures and 41 tables, and accompanied by various chronological notes of evolution, enables readers a friendly interaction with the book. Dr. Ben-Zion Maytal is a Senior Researcher at Rafael-Advanced Defense Systems, Ltd., and an Adjunct Senior Teaching Fellow at the Technion-Israel Institute of Technology, Haifa, Israel. Prof. John M. Pfotenhauer holds a joint appointment in the Departments of Mechanical Engineering and Engineering Physics at the University of Wisconsin - Madison.

This book is the first in English being entirely dedicated to Miniature Joule-Thomson Cryocooling. The category of Joule-Thomson (JT) cryocoolers takes us back to the roots of cryogenics, in 1895, with figures like Linde and Hampson. The "cold finger" of these cryocoolers is compact, lacks moving parts, and sustains a large heat flux extraction at a steady temperature. Potentially, they cool down unbeatably fast. For example, cooling to below 100 K (minus 173 Celsius) might be accomplished within only a few seconds by liquefying argon. A level of about 120 K can be reached almost instantly with krypton. Indeed, the species of coolant plays a central role dictating the size, the intensity and the level of cryocooling. It is the JT effect that drives these cryocoolers and reflects the deviation of the "real" gas from the ideal gas properties. The nine chapters of the book are arranged in five parts. •The Common Principle of Cyrocoolers shared across the broad variety of cryocooler types •Theoretical Aspects: the JT effect and its inversion, cooling potential of coolants, the liquefaction process, sizing of heat exchangers, level of pressurization, discharge of pressure vessels • Practical Aspects: modes of operation (fast cooldown, continuous, multi-staging, hybrid cryocoolers), pressure sources, configuration, construction and technologies, flow adjustment, MEMS, open and closed cycle, cooldown process and similarity, transient behavior • Mixed Coolant cryocooling: theory, practice and applications • Special Topics: real gas choked flow rates, gas purity, clog formation, optimal fixed orifice, modeling, cryosurgical devices, warming by the inverse JT effect The theoretical aspects may be of interest not only to those working with cryocoolers but also for others with a general interest in "real" gas thermodynamics, such as, for example, the inversion of the JT effect in its differential and integral forms, and the exceptional behavior of the quantum gases. A detailed list of references for each chapter comprises a broad literature survey. It consists of more than 1,200 relevant publications and 450 related patents. The systematically organized content, arranged under a thorough hierarchy of headings, supported by 227 figures and 41 tables, and accompanied by various chronological notes of evolution, enables readers a friendly interaction with the book. Dr. Ben-Zion Maytal is a Senior Researcher at Rafael-Advanced Defense Systems, Ltd., and an Adjunct Senior Teaching Fellow at the Technion-Israel Institute of Technology, Haifa, Israel. Prof. John M. Pfotenhauer holds a joint appointment in the Departments of Mechanical Engineering and Engineering Physics at the University of Wisconsin - Madison.

The Oregon Convention Center, Portland, Oregon, was the venue for the 1997 Cryogenic Engineering Conference. The meeting was held jointly with the International Cryogenic Materials Conference. John Barclay, of the University of Victoria, and David Smathers, of Cabot Performance Materials, were conference chairmen. Portland is the home of Northwest Natural Gas, a pioneer in the use of liquid natural gas, and Portland State University, where cryogenic research has long been conducted. The program consisted of 350 CEC papers, considerable more than CEC-95. This was the largest number of papers ever submitted to the CEC. Of these, 263 papers are published here, in Volume 43 of Advances in Cryogenic Engineering. Once again the volume is published in two books. CEC PAPER REVIEW PROCESS Since 1954 Advances in Cryogenic Engineering has been the archival publication of papers presented at the biennial CEC!ICMC conferences. The publication includes invited, unsolicited, and government sponsored research papers in the research areas of cryogenic engineering and applications. All of the papers published must (1) be presented at the conference, (2) pass the peer review process, and (3) report previously unpublished theoretical studies, reviews, or advances in cryogenic engineering.

This book serves as an introduction to cryocooler technology and describes the principle applications of cryocoolers across a broad range of fields. It covers the specific requirements of these applications, and describes how the advantages and disadvantages of different cryocooler systems are taken into consideration. For example, Stirling coolers tend to be used only in space applications because of their high coefficient of performance, low weight and proven reliability, whilst Gifford-McMahon coolers are used for ground applications, such as in cryopumps and MRI shield cooling applications. Joule-Thomson cryocoolers are used in missile technology because of the fast cool down requirements. The cryocooler field is fast developing and the number of applications are growing because of the increasing costs of the cryogens such as Helium and Neon. The first chapter of the book introduces the different types of cryocoolers, their classification, working principles, and their design aspects, and briefly mentions some of the applications of these systems. This introductory chapter is followed by a number of contributions from prominent international researchers, each describing a specific field of application, the cooling requirements and the cryocooler systems employed. These areas of application include gas liquefaction, space technology, medical science, dilution refrigerators, missile systems, and physics research including particle accelerators. Each chapter describes the cooling requirements based on the end use, the approximate cooling load calculations, the criteria for cryocooler selection, the arrangement for cryocooler placement, the connection of the cooler to the object to be cooled, and includes genuine case studies. Intended primarily for researchers working on cryocoolers, the book will also serve as an introduction to cryocooler technology for students, and a useful reference for those using cryocooler systems in any area of application.