High pressure optical cell for synthesis and in situ Raman spectroscopy of hydrogen clathrate hydrates Rev. Sci. Instrum. 83, 113101 (2012) Thermosize effects and irreversibility on the performance of a macro/nano scaled refrigeration cycle J. Appl. Phys. 112, 084325 (2012) Cell-encapsulating droplet formation and freezing Appl. Phys. Lett. 101, 133701 (2012) A compact and miniaturized high resolution capacitance dilatometer for measuring thermal expansion and magnetostriction Rev. Sci.

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... 83, 095102 (2012) Compact radio-frequency resonator for cryogenic ion traps Rev. Sci. Instrum. 83, 084705 (2012) Additional information on AIP Conf. Proc. Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. Same as Report (SAR) 18. NUMBER OF PAGES 9 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) ABSTRACT Pulse tube refrigerators (PTRs) have made dramatic improvements in reliability, efficiency and usage. Inertance tube PTRs have been one of the keys to these improvements. The inertance tube is the component in the PTR that most easily affects the control of the PTR fluid dynamics. In one application in multistage cryocoolers, the performance of inertance tubes at the cryogenic temperatures is of interest. One purpose of this paper is to understand how temperature and the size of the reservoir influence the phase shift between mass flow rate and pressure at the inlet of the inertance tube. Various models including a two dimensional Computational Fluid Dynamics (CFD) will be compared to understand how these models can predict the phase shift and the acoustic power.