Perspectives of Space Submillimeter Astronomy
St. Petersburg, Russia, 30 September - 2 October, 2002

Viewgaphs of the presentation

	V.D. Gromov. Cryogenic space telescope with cold electron nanobolometers array for submillimeter-wave astronomy
	Slide02 Project paricipants
	Slide03 Outline. Part 1.
	Slide04 Cosmic Microwave Background (CMB) is a relic of time when Universe was 10-5 of its present age. The spectrum of CMB was measured by bolometric instrument FIRAS on board of COBE satellite. NEPbol=10-14 W/Hz1/2.
	Slide05 Most of cosmologically distant sources are bright in submillimeter region and are invisible in optics as was shown by observation with ground-based SCUBA bolometer array. NEPbol=10-16 W/Hz1/2.
	Slide06 The CMB is remarkably uniform. An anisotropy less then 10-4 of its isotropic level was measured by bolometric instruments with balloon telescopes BOOMERANG and MAXIMA. NEPbol=2·10-17 W/Hz1/2.
	Slide07 Limits of detectors sensitivity at low background [Gromov 1983] are different for bolometric and coherent receivers. Fundamental advantage of direct detectors is a possiblility of unrestricted reducing of noise, while for coherent receivers noise temperature can not be less approximatly hν/k.
	Slide08 Greater improvements of bolometers can be achieved with novel technology
	Slide09 Andreev-Bolometer [Nahum, Martinis 1993] using tunnel junction (TJ)sensor. NEPbol=10-18 W/Hz1/2. Nanometric bolometer at temperature of milli-Kelvins is subject for Andreev physics.
	Slide10 Comparison of Thermistor Technologies
	Slide11 NEP comparision
	Slide12 Moor law for astronomy
	Slide13 16 point "jiggle" pattern needed for single image with usual horn antennae bolometric array [Griffin 2000] instead of 1 exposition for nanobolometers array.
	Slide14 Cold Electrons nanoBolometers with TJ as sensor and cooler (Chalmers University), an alternative for Transition Edge Sensor (TES) bolometers
	Slide15 Background Problem for TES bolometers. [Griffin 2000] Contradiction between sensitivity and workability in brighter regions of sky
	Slide16 Cold Electrons Bolometer (CEB) Noise improvement Background change adaptation Internal cooling reduces requirements for external cooling system
	Slide17 SQUID readout circuit for CEB This devices use TJ technology and are most perspective for nanobolometers array readout.
	Slide18 Practical Realization Al-Cr-Au Technology (Chalmers) instead Pb-Cu-Al [Nahum,Martinis,1993] CCNHEB device (Chalmers), AFM image and schematics.
	Slide19 Some conclusions

Part 2. Submillimetron project.

Gromov V.D. Quantum limit of radiation detectors at nonisothermal background. Space Research Institute, USSR Academy of Sciences, Moscow, 1983.

Griffin M.J. Bolometers for far-infrared and submillimetre astronomy Nuclear Instruments & Methods in Physics Research, Sect. A, v. 444, pp. 397-403, 2000.

Nahum, M.; Martinis, J.M. Ultrasensitive-hot-electron microbolometer Applied physics letters, v. 63, p. 3075, 1993.