Scientists use lasers to focus on various materials to stimulate shock waves, electromagnetic radiation, etc., to simulate the nuclear test environment and conditions; radiation-free fusion power generation has broad application prospects and can replace existing nuclear fission power generation, clean and safe, and resources rich. It can be said that laser pointer focused shooting is an important driving application for defense military experiments and long-term civil fusion power generation.
What is a target? Target, as the name implies, is the target’s point of attack, and its action is commonly referred to as target. Targets are mainly divided into two types: flat targets and cavity targets. The shape of a flat target is relatively simple. It is generally made of a certain material into a flat shape; the cavity target is a laser injection that strikes a certain cylindrical cavity or spherical cavity. The structure is relatively complex. The size of the two types of targets is generally in the order of mm, and the spot size of the laser beam focusing target is generally in the order of 100 microns.
The planar target is generally composed of a substrate and a film. The substrate is generally a certain metal (such as aluminum, copper, tungsten, gold, etc.), and the film is generally composed of a compound of hydrogen atoms (such as CH film, etc.). By hitting a flat target of different materials, you can study related shock waves, plasma spray , X-ray/gamma ray and other electromagnetic radiation effects.
The target pill in the cavity target is a tritium deuterium pellet. The cavity is made of a high-Z material with a large atomic number (such as tungsten, gold, lead, etc.), and the cavity wall is coated with some conducive to absorption and conversion of laser energy. Composite material. The size of the cylindrical cavity target is generally on the order of a few mm, so its preparation process is more complicated and delicate, and it is usually made by manual or mechanical arms under the control of a magnifying glass.
Because the atmospheric fluid resistance is too large and the impurity particles are too large under normal pressure, the target usually “lives” in a closed high vacuum environment to obtain the best detection conditions. The most common way is to completely enclose the target with a metal sphere-like structure.
Over the years, the morphology, structure and size of the target ball of the green laser pointer device have changed greatly around the development of changes in physical experiments. In the early 1990s, Shenguang I was a cylindrical spherical target chamber (central cylinder, semi-circular on both sides) with a size of about 1m; in early 2000, Shenguang II produced a larger cylindrical spherical target chamber and a circular target chamber with dimensions The expansion is about 2m; after 2010, the round target ball of the Shenguang II upgrade device is close to 3m. Although the target is very small, considering the diameter of the laser beam before focusing (usually 200~400mm), the number of tens of hundreds of laser beams, and the installation position of various probes, etc., the shape and size of the target ball have been continuously improved.