We perform a detailed experimental study of resistive cooling of large ensembles of highly charged ions such as ${\mathrm{Ar}}^{13+}$ in a cryogenic Penning trap. Different from the measurements reported by Vogel et al. [M. Vogel et al., Phys. Rev. A 90, 043412 (2014)], we observe purely exponential cooling behavior when conditions are chosen to allow collisional thermalization of the ions. We provide evidence that in this situation resistive cooling time constants and final temperatures are independent of the initial ion energy and that the cooling time constant of a thermalized ion ensemble is identical to the single-ion cooling time constant. For sufficiently high ion number densities, our measurements show discontinuities in the spectra of motional resonances which indicate a transition of the ion ensemble to a fluidlike state when cooled to temperatures below approximately 14 K. With the final ion temperature presently being 7.5 K, ions of the highest charge states are expected to form ion crystals by mere resistive cooling, in particular not requiring the use of laser cooling.We perform a detailed experimental study of resistive cooling of large ensembles of highly charged ions such as ${\mathrm{Ar}}^{13+}$ in a cryogenic Penning trap. Different from the measurements reported by Vogel et al. [M. Vogel et al., Phys. Rev. A 90, 043412 (2014)], we observe purely exponential cooling behavior when conditions are chosen to allow collisional thermalization of the ions. We provide evidence that in this situation resistive cooling time constants and final temperatures are independent of the initial ion energy and that the cooling time constant of a thermalized ion ensemble is identical to the single-ion cooling time constant. For sufficiently high ion number densities, our measurements show discontinuities in the spectra of motional resonances which indicate a transition of the ion ensemble to a fluidlike state when cooled to temperatures below approximately 14 K. With the final ion temperature presently being 7.5 K, ions of the highest charge states are expected to form ion crystals by mere resistive cooling, in particular not requiring the use of laser cooling.

arXiv:1809.08606Physical Review AAug 27, 201815 citations

The Resistive Transition of an Aluminium Hot Electron Bolometer Mixer with Normal Metal Cooling Banks

A. H. Verbruggen, T. M. Klapwijk, Wolfgang Belzig +1 more

We perform a theoretical analysis based on the superconducting proximity-effect model for the resistive transition of an aluminium superconducting hot electron bolometer mixer when the cooling banks are in the normal state. We compare our calculated result with a recently reported measurement. Our calculation qualitatively reproduces the observed feature in which the resistance drops quickly around Tc with decreasing temperature, but saturates at a value roughly being one half of the normal state resistance. It also opens the question about which type of cooling banks (normal or superconductor) is favourably for low noise performance.We perform a theoretical analysis based on the superconducting proximity-effect model for the resistive transition of an aluminium superconducting hot electron bolometer mixer when the cooling banks are in the normal state. We compare our calculated result with a recently reported measurement. Our calculation qualitatively reproduces the observed feature in which the resistance drops quickly around Tc with decreasing temperature, but saturates at a value roughly being one half of the normal state resistance. It also opens the question about which type of cooling banks (normal or superconductor) is favourably for low noise performance.

Softwaretechnik-TrendsDec 1, 20013 citations

Laser cooling

Ignacio Enrique Olivares Bahamondes, Patrick Carrazana

Institute of Physics eBooksSep 1, 20220 citations

Characterization of Quasi-Optical NbN Phonon-cooled Superconducting HEB Mixers

Ling Jiang, Wei Miao, Wen Zhang +10 more

--In this paper, we thoroughly investigate the performance of quasi-optical NbN phonon-cooled superconducting hot-electron bolometer (HEB) mixers, cryogenically cooled by a close-cycled 4-K refrigerator at 500 GI-1z and 850 GHz. The uncorrected lowest receiver noise temperatures measured are 800 K at 500 CHz without anti-reflection coating, and 1000 K @ 850 GHz with a 50 11M thick Mylar anti-reflection coating. The dependence of receiver noise temperature on the critical current and bath temperature of HEB mixer is also investigated here. Lifetime of quasi-optical superconducting NbN HEB mixers of different volumes, room temperature resistances, and critical temperatures are thoroughly studied. Increased room temperature resistance with time over the initial resistance changes between 1 and 1.2, and the reduced critical current with time over the initial value fluctuates slightly around 0.7 for most HEB mixers even of different volumes, room temperature resistances, and critical temperatures. The critical current degrades sharply vvhile room temperature resistance varies over 1.25.--In this paper, we thoroughly investigate the performance of quasi-optical NbN phonon-cooled superconducting hot-electron bolometer (HEB) mixers, cryogenically cooled by a close-cycled 4-K refrigerator at 500 GI-1z and 850 GHz. The uncorrected lowest receiver noise temperatures measured are 800 K at 500 CHz without anti-reflection coating, and 1000 K @ 850 GHz with a 50 11M thick Mylar anti-reflection coating. The dependence of receiver noise temperature on the critical current and bath temperature of HEB mixer is also investigated here. Lifetime of quasi-optical superconducting NbN HEB mixers of different volumes, room temperature resistances, and critical temperatures are thoroughly studied. Increased room temperature resistance with time over the initial resistance changes between 1 and 1.2, and the reduced critical current with time over the initial value fluctuates slightly around 0.7 for most HEB mixers even of different volumes, room temperature resistances, and critical temperatures. The critical current degrades sharply vvhile room temperature resistance varies over 1.25.

Softwaretechnik-TrendsMay 1, 20060 citations

Laser Cooling

Pierre Meystre

Graduate texts in physicsJan 1, 20210 citations

We perform a detailed experimental study of resistive cooling of large ensembles of highly charged ions such as

{\mathrm{Ar}}^{13+}

in a cryogenic Penning trap. Different from the measurements reported by Vogel et al. [M. Vogel et al., Phys. Rev. A 90, 043412 (2014)], we observe purely exponential cooling behavior when conditions are chosen to allow collisional thermalization of the ions. We provide evidence that in this situation resistive cooling time constants and final temperatures are independent of the initial ion energy and that the cooling time constant of a thermalized ion ensemble is identical to the single-ion cooling time constant. For sufficiently high ion number densities, our measurements show discontinuities in the spectra of motional resonances which indicate a transition of the ion ensemble to a fluidlike state when cooled to temperatures below approximately 14 K. With the final ion temperature presently being 7.5 K, ions of the highest charge states are expected to form ion crystals by mere resistive cooling, in particular not requiring the use of laser cooling.