| Presentation: | K. Arutyunov. (ppt). An interference effect was observed in a NIS microstructure. |
| Definitions: | A superconducting quantum interference device (SQUID) with SIS junctions is very sensitive device for current measurements. A question arises: Is it possible to build SQUID-like device with NIS junctions? (abbreviations are given in footnotes) |
| Prototype: | SQUID, commercially available device using industry approved SIS junction technology |
| Discussion: | K. Arutyunov. Minutes |
| Pro: | NISI is a new interesting device. It might appear a strong competitor to a conventional SQUID. |
| Contra: | Physics involved should be clarified. Contribution of the self-inductance should be considered. |
| Presentation: | N. Oukhanski. (ppt). A measured cooled PHEMT noise figure was TN = 50 -100 mK at frequencies 1-30 MHz. |
| Definitions: | Low noise bolometer readout circuits widely used for astronomy and space applications are optimized for frequencies between mHz and kHz and based on JFET, MOSFET or SQUID elements. PHEMT is a most sensitive device in microwave (GHz) region. Are any bolometer applications where PHEMT is competitive? (abbreviations are given in footnotes) |
| Prototypes: | JFET, MOSFET, bipolar-transistor. In 1970's noncooled p-JFET noise figure was TN < 50 mK at frequencies 1-100 kHz. |
| Discussion: | N. Oukhanski. Minutes |
| Pro: | It is very promising to use resonant PHEMT readout technique for CEB frequency domain multiplexing. |
| Contra: | No CEB device demonstration was made at frequencies higher than a few kHz.
Measurements of readout noise with modern JFET at optimal cooling should be conducted for comparison. |
| Presentation: | A. Vystavkin at a 10th LTD conference (ref., pdf) |
| Definitions: | For an N x N pixels image an N x N detector array with N 2 readouts usually used.
The method uses N x N detector array with N outputs. Each of them sum signals of each row. A set of M rotated positions of the array in image plane is used to restore second dimension of the image. The N x N image then should be reconstructed using computer methods from N x M readouts, M>N. |
| Prototypes: | N x N detector array with each pixel readout using FDM or TDM methods of multiplexing |
| Discussion | |
| Pro: | Possibilities: to reduce drastically amounts of wires connected to detectors, to simplify the scheme, and to increase significantly a signal-to-noise ratio in the system. |
| Contra: | Reduction of signal-to-noise ratio (and NEP) due to decrease of integration time for each readout (M>N), increase of noise due to summation of detector noises in a raw, dramatic decrease of signal-to-noise ratio during computer reconstruction (inverse problem). |
| Presentation: | L. Kuzmin, M. Tarasov. |
| Definitions: | Carbon nanotube with cross section of a few nm2 should be used in CEB as absorber instead of metal strip with cross section more than 104 nm2. (CEB, TES, KID abbreviations are given in footnotes) |
| Prototypes: | Normal or superconducting metal absorbers of CEB, TES, KID bolometers |
| Discussion | |
| Pro: | Extremely low volume of absorber is promising for high sensitivity in the case of high absorption efficiency |
| Contra: | Physics involved should be clarified. Mechanism of absorption is not determined. |
| Presentation: | Vladimir Mikheev, Simon Mitchenson (ppt). Michael Tarasov (ppt). |
| Definitions: | Cryofree (cryogen-free) refrigerators are systems not using cryogenic liquids. They don't need refilling liquid helium and nitrogen filling before a work. Some OI systems don't use cryo-liquids because a cryo-gas is maintained at supercritical temperature. |
| Prototypes: |
He-3 refrigerator FIAN. Troitsky 1984
He-3 sorption cooler/pulse tube CEA/SBT. Duband 1990, 2002, Dilution refrigerator KIPP. Edelman 2002 |
| Discussion: | S. Mitchenson. Minutes |
| Pro: | Wide range of applications: University laboratory experiments, ground-based and airborne astronomical observations. |
| Contra: | Mechanical vibration is a possible source of excess noise of detectors. Cooling parameters should be compared with that of prototypes. |
Vystavkin, A. N.; Pestriakov, A. V. The multiplexing of signals in direct detector arrays using projections method. Proceedings of the 10th International Workshop on Low Temperature Detectors. Nuclear Instruments and Methods in Physics Research Section A, v. 520, p. 562-565. (pdf)
V. Troitskii, A. Fradkov. Portable 3He refrigerator. Pribory i Tekhnika Eksperimenta, v. 27, 1984, p. 210-212.
Duband, L.; Alsop, D.; Lange, A.; Kittel, P. A rocket-borne He-3 refrigerator.
Advances in cryogenic engineering. Vol. 35B , 1990, p. 1447-1456.
"The first cryogen free system covering the range 300 K-300 mK":
Duband, L.; Clerc, L.; Ravex, A. Socool: A 300 K-0.3 K pulse tube/sorption cooler.
ADVANCES IN CRYOGENIC ENGINEERING: V. 613, pp. 1233-1240 (2002).
L. Duband. Sorption coolers versus ADR.
The 6th International Workshop "From Andreev Reflection to the International Space Station"
Bjorkliden, Kiruna, Sweden, April 4-11, 2002. Viewgaphs
A work done before Troitskii 1984 :
Simon. The proceedings of the
physical society, Vol. 60 part 5, 1 May 1948, no. 341
A quantitative study of the expansion method for liquefying helium.
Scott and Cook. The review of scientific Instruments, Vol. 19 no.12
December 1948. A Simon-type helium liquefier with transfer siphon.
Edelman, V.S. Operation of a dilution refrigerator in a micromode. Pribory i Tekhnika Eksperimenta, n. 3, 2002, p. 139-144.
ADR - Adiabatic Demagnetization Refrigerator
CEA/SBT - Service des Basses Temperatures, Grenoble, France
CEB - Cold Electron Bolometer
FDM - Frequency Domain Multiplexing
FIAN - P.N.Lebedev Physical Institute, Moscow
JFET - Junction Field-Effect Transistor
He-3 - Helium isotope 3He
HEMT - High Electron Mobility Transistor with a heterojunction as a channel
KID - Kinetic Inductance Detector
KIPP - P.L.Kapiza Institute of Physical Problems, Moscow
MOSFET - Metal-Oxide-Semiconductor Field-Effect Transistor
NEP - Noise Equivalent Power, a detector sensitivity threshold value
NIS - "Normal metal - Insulator - Superconductor"
NISI - NIS interferometer
PHEMT - Pseudomorphic HEMT using different lattice constant materials for a heterojunction
SIS - "Superconductor - Insulator - Superconductor"
SQUID - Superconducting Quantum Interference Device
TDM - Time Domain Multiplexing
TES - Transition Edge Sensor