[en] Some problems relating to cryopumps for selective pumping of impurity gases in the ''Globus'' tokamak are considered. The dependence on geometry of the pumping speed of the system was determined in molecular regime and taking into account the influence of unpumped hydrogen. The values of the heat load of the cryopumping systems are estimated under different operating conditions. Several types of cooling system are proposed. (Author)

[en] Within the framework of the European fusion technology programme, a primary vacuum pump for international thermonuclear experimental reactor (ITER) is being developed. As the tritium inventory accumulated by the pumps must be limited, short pumping cycles are required. At two facilities, different fast heating and cooling techniques of cryosorption panels were investigated. The results for the most advantageous methods are presented. It is shown that fast regeneration of ITER cryopanels is technically feasible. (orig.)

[en] The purpose of the paper is to raise and discuss problems connected with possible operating conditions of a helium condensation pump (HCP) with a capacity of 10⁶ l/s and higher, designed to pump out hydrogen in hot, thermonuclear, in particular, systems, and discussion of functional modes of a helium cryogenic supply system. This makes possible the development of efficient pumps with a low energy-rate factor W/S, where W is the power required for operation of the refrigerating device, determined by the amount of heat supplied to the cryogenic pumps and by the efficiency of the refrigerating device; S is the pumping rate of the HCP. It is shown that the geometry of the pumping-out system and of the cryogenic supply system should be selected with provision for the results of the analysis of factors listed in the tables and for operating conditions of cryogenic pumps. Model experiments showed that it is possible to construct HPC for pumping out hydrogen with a rather high energy-rate factor equal to (2-3)x10^-2 W/l/s

[en] The special problems related to the operation of the cryopumpsystems at JET during the active (D/T) phase are reviewed. The main aspects are the effects of neutrons - thermal load and activation of the cryogenic fluids and structure - the tritium inventory and safety, the radiation compatibility of cryostructure and instrumentation and the production of hazardous ozone under radiation conditions. Most of the results of the analysis can be applied to any other fusion cryosystem by appropriate scaling. (author). 9 refs.; 2 figs.; 3 tabs

[en] The cryogenic department of the IPN realized a cryopump of the liquid helium bath type. Performances are measured (pumping speed, consumption of cryofluids, holding time)

No abstract available

[en] A cryogenic pump is described, specially designed to be used in an electrostatic particle accelerator. The same tubular liquid helium bath provides pumping in the accelerating tube and around the beam. The temperature of the bath can be adjusted between 2.2 and 4.2 deg K, the liquid helium level, in the low pressure bath, is keeped constant through a feeding system made of an heat exchanger and an expansion valve. An auxiliary container for liquid nitrogen and liquid helium, at atmospheric pressure, allows a several days continuous run without filling. This system allows refilling of the container without changing the pressure on the bath

No abstract available

[en] A vacuum post for pumping-out of devices, used for adsorbents investigation, is described. Such vacuum post, generating pure oilless vacuum, is necessary to regenerate adsorbents under investigation. Pure oilless vacuum is produced with the help of two forevacuum pumps with the following pumping-out with highvacuum adsorption and titanium pumps. Adsorption pumps are cooled by liquid nitrogen. It is established in the result of the test of vacuum post with four devices with adsorbents connected with it, that using only adsorbtion pumps for pumping-out the pressure of P = 10^-1 Pa is achieved in devices; after preliminary blowing of all system with dry nitrogen P=10^-2 Pa; during the simultaneous operation of adsorption and titanium pumps at two-hour heating of devices with adsorbents P=6x10^-3 Pa, and at 6-hour heating P=3.2x10^-4 Pa. The limit vacuum, achieved by vacuum post, is equal to 5x10^-5 Pa with devices P=1.2x10^-4 Pa. The devices heating has been carried out at 200 deg C. All post sealings are resin. Described vacuum post permits to accelerate adsorbent regeneration in devices without pollution of studied adsorbent with working substance of pumps

[en] Design of a supersonic source with a plane skimmer and a cryopumped expansion chamber is described. Performance measurements of the cryopump were done using flow rates up to 5 torr l/s for Ar and N₂. Absolute centerline beam intensities and off-centerline intensity-profiles were determined. With argon a centerline intensity of 4.7 10¹⁸ molecules sterad^-1s^-1 was obtained at a nozzle flow of 8.2 10¹⁸ molecules s^-1