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Mel’nikov AP, Gurvich YA, Shestakov LN, Gershenzon EM. Magnetic field effects on the nonohmic impurity conduction of uncompensated crystalline silicon. Jetp Lett. 2001;73(1):44–7.
Abstract: The impurity conduction of a series of crystalline silicon samples with the concentration of major impurity N ≈ 3 × 1016 cm−3 and with a varied, but very small, compensation K was measured as a function of the electric field E in various magnetic fields H-σ(H, E). It was found that, at K < 10−3 and in moderate E, where these samples are characterized by a negative nonohmicity (dσ(0, E)/dE < 0), the ratio σ(H, E)/σ(0, E) > 1 (negative magnetoresistance). With increasing E, these inequalities are simultaneously reversed (positive nonohmicity and positive magnetoresistance). It is suggested that both negative and positive nonohmicities are due to electron transitions in electric fields from impurity ground states to states in the Mott-Hubbard gap.
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Hsiao FZ, Lin MC, Wang C, Lee DS, Chen JR, Hilbert B, et al. The liquid helium cryogenic system for the superconducting cavity in SRRC. In: Proc. Particle Accelerator Conference. Vol 2.; 2001. p. 1604–6.
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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Kroug M. Hot electron bolometric mixers for a quasi-optical terahertz receiver [Ph.D. thesis]. Chalmers University of Technology, Gothenburg, Sweden; 2001.
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Gershenson ME, Gong D, Sato T, Karasik BS, Sergeev AV. Millisecond electron-phonon relaxation in ultrathin disordered metal films at millikelvin temperatures. Appl. Phys. Lett.. 2001;79:2049–51.
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Karpov A, Miller D, Rice F, Zmuidzinas J, Stern JA, Bumble B, et al. Low noise 1.2 THz SIS receiver. In: Jet Propulsion Laboratory CIit.u.t.e of T, editor. Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 21–2.
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Shi SC, Chin CC, Wang MJ, Shan WL, Zhang W, Noguchi T. Development of a 600–720 GHz SIS Mixer for the SMART. In: Jet Propulsion Laboratory CIit.u.t.e of T, editor. Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. 215.
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Cherednichenko S, Kroug M, Merkel H, Kollberg E, Loudkov D, Smirnov K, et al. Local oscillator power requirement and saturation effects in NbN HEB mixers. In: Jet Propulsion Laboratory CIit.u.t.e of T, editor. Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 273–85.
Abstract: The local oscillator power required for NbN hot-electron bolometric mixers (P LO ) was investigated with respect to mixer size, critical temperature and ambient temperature. P LO can be decreased by a factor of 10 as the mixer size decreases from 4×0.4 µm 2 to 0.6×0.13 µm 2 . For the smallest volume mixer the optimal local oscillator power was found to be 15 nW. We found that for such mixer no signal compression was observed up to an input signal of 2 nW which corresponds to an equivalent input load of 20,000 K. For a constant mixer volume, reduction of T c can decrease optimal local oscillator power at least by a factor of 2 without a deterioration of the receiver noise temperature. Bath temperature was found to have minor effect on the receiver characteristics.
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Kroug M, Cherednichenko S, Choumas M, Merkel H, Kollberg E, Hübers H-W, et al. HEB quasi-optical heterodyne receiver for THz frequencies. In: Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 244–52.
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Merkel HF, Khosropanah P, Sigfrid Yngvesson K, Cherednichenko S, Kroug M, Adam A, et al. An active zone small signal model for hot-electron bolometric mixers. In: Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. 55.
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Betz AL, Boreiko RT, Sivananthan S, Ashokan R. HgCdTe photoconductive mixers for 2-8 THz. In: Jet Propulsion Laboratory CIit.u.t.e of T, editor. Proc. 12th Int. Symp. Space Terahertz Technol. San Diego, CA, USA; 2001. p. 92–101.
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