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The gauge transformation of the hydrodynamic equations of superfluidity and superconductivity is considered. The vortex and heat momentum densities are defined and their evolution equations are derived. The physical meaning of these quantities is analyzed. The Lagrangian invariants of the new set of equations, which are similar to those obtained by Hollman for classical hydrodynamics, are derived.

A number of time analysing image converter tubes integrated with thinned, backside illuminated,electron bombarded (EB) CCDs was developed. Among them are PVOO 1 , PVOO3 , and PIFO 1 streak tubes differing from each other by their internal electron optics and external (metal-glass or metal-glass-ceramic) geometry. All tested EB CCD/streak tubes reveal a relatively good behaviour refering to the long term stability of their input S 1 photocathode and reproducibility of the matrix parameters. These tubes advantageously differ from their regular type, phoshor screen analogoues by rather high spatial resolution ( >40 lp/mm at 10% MTF for PV tyje tubes and >25 lp/mm at 10% MTF for PIF type tubes) , reasonably good threshold sensitivity of 10 J/cm2 in standard, 10 MHz CCD scanning mode at 850 nm input radiation, picosecond temporal resolution ( better 5 ps) at relatively acceptable value of the light transfer function ( -102). 2.INTRODUCTIONAmong problems in picosecond streak image technique which require fast solution, let us mention the followings: to simplify streak cameras maintaining, to match them with a personal computer in order to automate the process of quantative data recording processing and presentation, to improve streak systems realiability, and to reduce their cost. A promising approach in solving of some of the mentioned problems consists in replacing traditional luminescence screen in streak image tubes by a thinned, backside illuminated, electron bombarded (EB) 2 The rear face bombardment by 5-20 keY photoelectrons makes the detection of every incident electron a possibility3 due to high EBS gain in silicon, ranging from 50 to 3 .5 • 1o. Since the EBS cascade process takes place close to the rear face, it becomes necessary to thin the CCD up to 8-15 m in order to conserve both sensitivity and spatial resolution46.The replacement of phosphor screen with EB CCD sensors was successfully demonstrated by various group of authors who have developed a set of very sensitive image intensifiers for low light level vision79. However, to our knowledge, almost no reports besides a paper of J.C.Cheng et were published on EB CCD introduction in a vacuum body of ultrafast streak tubes.In 1988 we have presented our first experimental results on fabrication and static measurements of a picosecond streak tube incorporated with a thinned, backside illuminated EB CCD matrix2. Spatial resolution of our integrated EB CCD/PVOO3 tube was better than 40 lp/mm and its sensitivity was much higher than the sensitivity of the same tube but supplied with a regular luminescence screen These experiments encouraged us to continue investigations in designing a reliable and reproducible EB 94

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