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Hsiao, F. Z., Lin, M. C., Wang, C., Lee, D. S., Chen, J. R., Hilbert, B., et al. (2001). The liquid helium cryogenic system for the superconducting cavity in SRRC. In Proc. Particle Accelerator Conference (Vol. 2, pp. 1604–1606).
Abstract: A 500 MHz superconducting cavity will replace the current copper cavity and begin to operate in the beginning of the year 2003. A liquid helium cryogenic system provides the cavity at 4.5 K a cooling capacity of 255 W without LN2 pre-cooling and a liquefaction rate of 110 liter/hour with LN2 pre-cooling. A safety factor of 1.5 is used to estimate the heat load from the superconducting cavity and the heat loss from the transfer lines. With the LN2 pre-cooling, this cooling system provides a cooling capacity of up to 450 W to cool down the additional superconducting Landau cavity. The capacity of the system can be tuned using a frequency driver installed at the compressor station. The pressure fluctuations of the dewar and of the suction line are kept to the same stability requirement that of the cavity cryostat to minimize the influence in cavity operation. A shutdown period for maintenance of more than 8000 hours for the cryogenic system is expected without interfering with the continuous operation of the superconducting cavity.
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Smirnov, A. V., Larionov, P. A., Finkel, M. I., Maslennikov, S. N., Voronov, B. M., & Gol'tsman, G. N. (2008). NbZr films for THz phonon-cooled HEB mixers. In Proc. 19th Int. Symp. Space Terahertz Technol. (pp. 44–47). Groningen, Netherlands.
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Divochiy, A., Marsili, F., Bitauld, D., Gaggero, A., Leoni, R., Mattioli, F., et al. (2008). Superconducting nanowire photon-number-resolving detector at telecommunication wavelengths. Nat. Photon., 2(5), 302–306.
Abstract: Optical-to-electrical conversion, which is the basis of the operation of optical detectors, can be linear or nonlinear. When high sensitivities are needed, single-photon detectors are used, which operate in a strongly nonlinear mode, their response being independent of the number of detected photons. However, photon-number-resolving detectors are needed, particularly in quantum optics, where n-photon states are routinely produced. In quantum communication and quantum information processing, the photon-number-resolving functionality is key to many protocols, such as the implementation of quantum repeaters1 and linear-optics quantum computing2. A linear detector with single-photon sensitivity can also be used for measuring a temporal waveform at extremely low light levels, such as in long-distance optical communications, fluorescence spectroscopy and optical time-domain reflectometry. We demonstrate here a photon-number-resolving detector based on parallel superconducting nanowires and capable of counting up to four photons at telecommunication wavelengths, with an ultralow dark count rate and high counting frequency.
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Tarkhov, M., Claudon, J., Poizat, J. P., Korneev, A., Divochiy, A., Minaeva, O., et al. (2008). Ultrafast reset time of superconducting single photon detectors. Appl. Phys. Lett., 92(24), 241112 (1 to 3).
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Cherednichenko, S., Kollberg, E., Angelov, I., Drakinskiy, V., Berg, T., & Merkel, H. (2005). Effect of the direct detection effect on the HEB receiver sensitivity calibration. In Proc. 16th Int. Symp. Space Terahertz Technol. (pp. 235–239). Göteborg, Sweden.
Abstract: We analyze the scale of the HEB receiver sensitivity calibration error caused by the so called “direct detection effect”. The effect comes from changing of the HEB parameters when whey face the calibration loads of different temperatures. We found that for HIFI Band 6 mixers (Herschel Space Observatory) the noise temperature error is of the order of 8% for 300K/77K loads (lab receiver) and 2.5% for 100K/10K loads (in HIFI). Using different approach we also predict that with an isolator between the mixer and the low noise amplifiers the error can be much smaller.
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