Liquid helium temperature cryogenic target for impact compression test

Abstract

The invention relates to a liquid helium temperature cryogenic target for impact compression test, which comprises an air-cooled screen cavity formed by an air-cooled screen inner barrel, an air-cooled screen outer barrel and a spiral groove on the wall of the inner barrel. The air-cooled screen inner barrel is provided with a front baffle plate, a neck pipe, an assembly, a corrugated pipe and a rear baffle plate in turn from front to back; and the assembly is provided with a liquid helium side tank, a liquid helium tank, a sample chamber, a probe, a thermometer, a return gas winding pipe, a sample gas inlet pipe, a liquid helium inlet pipe, a helium steam outlet, a joint and the like. Based on continuous liquid helium delivery and reduced pressure cooling, heat leakage of an environment on the sample chamber and the liquid helium tank is reduced by using combination of helium steam sensible heat and high-vacuum heat insulation; through a reasonable sealed structure, difficulties of low vacuum, low liquid helium latent heat, small liquid helium tank volume, small cryogenic target size and low-temperature seal on storage of liquid helium in the liquid helium tank and sample helium liquefaction are overcome; and the purpose of obtaining a stable liquid sample at any temperature of between 3.6 and 80K is fulfilled by controlling the power of a heating wire.

Description

technical field [0001] The invention belongs to the field of refrigeration and low temperature, and in particular relates to a liquid helium temperature low temperature target used for shock compression experiments to obtain uniform and stable liquid samples at 3.6K to 80K. Background technique [0002] The main technical requirements of the liquid helium temperature cryogenic target are as follows: 1. Accurate and controllable in the large temperature range of 4.2K ~ 80K, which can directly liquefy high-purity helium, hydrogen, deuterium and other sample gases, and can be directly used in liquid helium, liquid hydrogen, liquid Low temperature targets such as deuterium. 2. After the sample is liquefied, the temperature is stable and the density is uniform. 3. The consumption of liquid helium is as little as possible, and the cooling time is as short as possible. 4. There should be no obstacles between the target plate and the shrapnel. The structure size of the low-tempera...

AI Technical Summary

Problems solved by technology

Foreign low-temperature target devices only use the liquid helium pool to reduce the heat leakage from the environment to the sample chamber. If such a structure is applied to a 100Pa vacuum environment, there will be the following problems: First, the ambient temperature of 300K will affect the annular liquid helium pool through radiation and heat conduction. And the heat leakage of the liquid helium pool is very large, it is difficult to realize the storage of liquid helium

Second, the ambient temperature of 300K has a large heat leakage to the sample chamber through radiation and heat conduction, which makes the sample unable to liquefy; third, the structure does not make full use of the sensible heat of helium vapor, thereby increasing the consumption of liquid helium; fourth, The liquid helium pool with this structure has a larger volume and stores more liquid helium, which increases the risk of the experiment

[0005] Due to the high permeability of helium, the low-temperature target must have high sealing performance; the low latent heat of liquid helium and the small volume of the liquid helium pool require that the low-temperature target must have a good thermal insulation design, so the development of the liquid helium temperature low-temperature target has certain advantages. High technical barriers, although domestic research on liquid impact compression experiments has been carried out, a liquid nitrogen temperature cryogenic target ( figure 2 ), but there is no open literature about the liquid helium temperature cryogenic target supporting the secondary light gas gun in China

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