Figure3 Optical microscope under observation

1. Understanding of the nuclear-film manufacturing principles

When the high-energy charged particles (fission fragments) through the polymer plastic film, the particles in the path, the plastic polymer chain were broken, leaving a narrow channel injury - nuclear track。Without a nuclear deal with the original track can not be used microscopes and electron microscopy directly observed. However, due to track the polymer chain was destroyed, a lot of free radicals, highly active chemicals, chemical reagents can easily be corrosion, to use a microscope can be observed in the porous. Charged particles through the process of a substance known as irradiation, a process of photographic camera. Chemical reagents corrosion nuclear track process is known as etching, a photographic image in the process.
Fig4 The C3 in a material CR-39 left the track in the AFM image

Plastic film in the nuclear track through proper handling of etching and chemical conditions, we can control the porous density and aperture size. People found that the production of porous plastic film there are many uses. This porous membrane called the nuclear track etched membrane (nuclear track-etched membrane), who Nuclepore membrane of foreign goods in China said the nuclear membrane hole.
Its specific manufacturing processes are as follows. First, the use of the reactor shielding the large number of thermal neutron bombardment of uranium 235 targets, some of uranium 235 in the atomic nucleus fission, the high-energy fissile fissile debris close to the speed of the speed of light bombardment of plastic film, plastic film in the form of track damage. Then, graphics imaging technology, in the original film, formed by the needs of exquisite design. Finally, etching technology in plastic film received by the cylindrical-shaped micro-porous composition of the nuclear track patterns of white membrane.　 Fig5 Track after the film etched SEM? 　Nuclear membrane-specific parameters:

1. Material: Polyester（PET）
2. Micro aperture :0.004-0.006 mm
3. - Density: 4-8 × 10⒌ Hole / cm2
4. Hole inclination distribution: 0 to 50 degrees
5. Micro Distribution: Random
6. Hole oblique direction Distribution: Random
7. Nuclear track the history of development of technology

Nuclear track in the early development, scientists with Wilson cloud chamber to detect nuclear particle tracks. That is, in the cavity filled with a vapor, when the nuclear particles through the cloud chamber, in its left on the path of a white track, and then keep track camera images. By measuring the distance and the track direction, we can know the size of the particle, energy and direction. Room size due to fog, cloud track to retain a short time, the need to take pictures left-track, very easy to use, but solid track being gradually replaced by a detector.
1960s by the U.S. General Electric Company laboratory RLFIEischer and others on a solid track detectors, when the high-energy particle radiation to the nuclear non-conductive material, the particles in the path, the non-conductive polymer material was interrupted Or lattice were displaced, at normal temperature for a long time to retain the nuclear track, and then the track can be used chemical reagents etched out on track the length and size and direction can be calculated that particles of energy, size And the direction of the incident。
R.L.FIEischerAnd others were on solid track detectors on the basis that when the nuclear radiation and particles penetrate plastic film, after etching in the plastic film can create a hole, the aperture can be made uniform, through a hole-shaped track - Film Company (Nuclepore Corporation), started the commercialization of the nuclear-film production. China is in the early 1980s, as the "June 5" science and technology research project started nuclear-membrane system, to the late 1980s has been a considerable scale of production capacity.
To the 1990s, the anti-counterfeiting of products to market requirements, the National Security Zhongshan Torch Hi-tech Development Co., Ltd. carrying nuclear technology, Design and Research Institute of Qinghua University in the nuclear membrane hole on the basis of conduct nuclear track security film studies. Use of the unique graphics imaging technology, the design based on user needs, through selective radiation or etching, plastic film in the local-made nuclear membrane, as the porous to diffuse light, the formation of a specific white logo. Nuclear track security by the late film production or a combination of commercialization of other anti-counterfeiting technology, by nuclear track comprehensive security logo or other types of nuclear track security logo.