JPH0531519B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention involves adding a specific amount of an additive such as carbon black to a secondary explosive such as a pen slit to adjust the specific gravity to a specific gravity.
It relates to a method of irradiating a laser beam with a pulse width of 11 μm and a pulse width of 0.1 to 10 ms to initiate an explosion. (Prior technology) High-power laser oscillation devices include ruby laser, YAG (yttrium), and solid-state laser.
Aluminum garnet) lasers, gas lasers include carbon dioxide lasers, etc. Laser oscillation methods include continuous oscillation and pulse oscillation. Among them, pulse oscillation method has pulse width
Normal pulse oscillation of about 0.1~10ms and pulse width 1~
There is a pulse oscillation method using a Q switch that generates a huge pulse in a short period of about 10 ns. Figure 1 shows the output characteristics of laser light in normal pulse oscillation and Q-switch oscillation methods. The pulse width of the former is ms
order and the output is large, whereas the latter is
It has a large power of ns order. Conventionally, using the above laser beam, one of Penslit (hereinafter referred to as PETN), tetryl, or hexogen (hereinafter referred to as RDX) is used, and this has a two-tier chamber structure, upper and lower. The chamber consists of an explosive whose specific gravity has been adjusted so that it will deflagrate when irradiated with a laser beam, and a metal plate is placed in contact with the surface opposite to the surface irradiated with the laser beam. After the upper explosive receives laser light and deflagrates, the gas pressure adjusts the specific gravity to such a value that it will detonate when the metal plate hits the lower explosive. There is a gap between it and the chamber to allow the metal plate to fly out. In this case, US Pat. No. 3,528,372 discloses a method in which the laser light used is not particularly limited as long as it has sufficient power or output to deflagrate the upper stage explosive. Other examples include PETN, tetryl,
One type of explosive consisting of RDX is used, and a metal plate is placed in contact with the side that is irradiated with the laser beam, and then regular pulsed or pulsed laser beam using a Q switch is applied. US Pat. No. 3,812,783 discloses a method of irradiating the metal plate to instantaneously vaporize the metal plate and generate a shock wave to detonate the explosive in contact with the metal plate. As another example, US Pat. No. 4,391,195 discloses a method of irradiating tricinate, which is a detonator, with ordinary pulsed laser light to detonate it. Furthermore, a method of adding a laser light absorbing substance to a secondary explosive such as PETN, RDX, or HMX and detonating it by irradiating it with pulsed laser light using a Q switch is described in "Industrial Explosives" Vol. 44, No. 5 ( 1983), 281~
It is described on page 287. (Problem to be solved by the invention) As described above, the method of detonating secondary explosives such as PETN, tetryl, RDX, etc. using laser light and using some kind of auxiliary means is structurally complicated. It has become a thing. In addition, in the case of methods using tricinate, etc., which are explosives, several
It can be detonated by direct irradiation with normal pulsed laser light of 10 to several 100 mJ, and as the detonator is highly sensitive to heat and shock, it must be handled with care. Furthermore, the method of adding a laser light absorbing substance and using a Q-switched pulse laser has problems in practical application because the adjustment of the device is delicate and the device is large. Therefore, as a result of intensive research over a long period of time, the inventors of the present invention took into account the above-mentioned problems.
By mixing a specific amount of a laser light absorbing material such as carbon black with a secondary explosive such as PETN, and adjusting the specific gravity of this mixture to a specific range, it easily absorbs the infrared heat energy of the laser and heats the explosive. We discovered that it is possible to do this without using a Q-switch oscillation type pulsed laser beam, which has a large power and is good for instantaneous energy injection, but requires delicate adjustment of the output device. It was discovered that it was possible to detonate using an oscillation type laser beam, and the present invention was completed. (Means for Solving the Problems) That is, the present invention provides a method for irradiating an explosive to which a laser light-absorbing substance is added by irradiating it with a laser beam. 0.5 to 10% by weight of one or more laser light absorbing substances selected from the group consisting of carbon black, graphite, and black dye is added to one or more secondary explosives to give a specific gravity of 1.1 to 1.1. Explosives adjusted to 1.4, with a wavelength of 0.6 to 11 μm,
This is a method of detonating explosives using laser light, which is characterized by irradiating laser light with a pulse width of 0.1 to 10 ms to detonate it. To briefly describe the detonation mechanism of explosives using laser light, when an explosive is irradiated with a huge pulse of laser light from a Q switch, the detonation starts mainly in response to the impact of the laser light irradiation. When an explosive is irradiated with a normal pulse of laser light, it starts detonating primarily in response to the thermal energy of the laser light. Therefore, the explosive used in the present invention must be an explosive that can effectively absorb the thermal energy of the laser beam and also initiate detonation using the thermal energy. Specifically, carbon black or the like is used as a material that absorbs the thermal energy of the laser beam, and PETN or the like is used as the main explosive. do
The explosive must be such that the particles, such as PETN, are effectively heated and reacted to initiate the detonation. To do this, the specific gravity of PETN etc. must be set to a specific gravity,
It is necessary to set the specific gravity of an explosive such as PETN to which carbon black or the like is added in a specific ratio to a specific specific gravity. Here, the specific gravity of the explosive used in the present invention will be described. The lower the specific gravity of the explosive, the smaller the amount of the explosive and additive per unit volume, and therefore the greater the amount of laser light irradiated per unit particle of the additive. Therefore, the temperature when heated becomes high. Furthermore, since the amount of explosive particles in the vicinity of the additive heated by absorbing laser light is small, the explosive particles are easily heated. In other words, a hot spot is formed, and detonation by laser beam irradiation can be easily achieved. However, in practical terms, the lower limit is a specific gravity of 1.1, considering the speed of detonation and ease of handling. Further, the upper limit should be 1.4 as a result of the experiment for the above-mentioned reason. If it exceeds this range, the object of the present invention cannot be achieved because it becomes non-explosive. Further, the purpose of adding the additive is to efficiently absorb infrared thermal energy of laser light with a wavelength of 0.6 to 11 μm. The additives used for this purpose must be carbon black, graphite, black dye. The addition ratio of the additive is such that laser light can be efficiently absorbed, and is 0.5 to 10% by weight.
If the addition ratio is too low or too high, the explosive cannot be completely detonated. The particle size of the explosive and the additive is not particularly limited, but the finer the particle size (usually about 50 mesh passes or less), the larger the contact area between the explosive and the additive, and the better the heat conduction from the additive to the explosive. Due to these features, it is possible to detonate using a normal pulsed laser beam without using any auxiliary means. (Effects of the Invention) According to the method of detonating an explosive using a laser beam of the present invention, which specifies the specific gravity of the explosive and the addition of a laser light absorbing substance within a specific range, it is possible to use the method of detonating an explosive with a laser beam of the present invention, in which the specific gravity of the explosive and the addition of a laser beam absorbing substance are specified within a specific range. The complex structure of the detonator,
The sensitivity can be improved even without using a complicated detonator structure with a metal plate placed on the laser beam irradiation surface, or without using a Q-switch pulse laser that is difficult to adjust and requires a large device to emit a huge pulse in a short time. It is possible to detonate secondary explosives such as PETN with a normal pulse of laser light, and with a relatively small energy of several joules, without using a detonator that has a high value and must be handled with care. It is possible to obtain unprecedented excellent effects such as miniaturization of the laser oscillation device, ease of adjustment, and safety due to slower detonation. (Example) Next, the present invention will be specifically explained with reference to Examples. Examples 1 to 20 The amount of carbon black added was 0.5, 1.0, 2.0,
The specific gravity of PETN mixed with the carbon black was changed to 5.0 and 10.0% by weight, respectively, and the specific gravity was changed to 1.10 and 1.10, respectively.
Explosive samples adjusted to 1.15, 1.20, and 1.40 were prepared. The particle size of PETN is 60-80 mesh pass 18% by weight, 80-100 mesh pass 47% by weight,
100-150 mesh pass 21% by weight, 150-200 mesh pass 13% by weight, 200 mesh pass or less 1% by weight
I used a moderate amount. Further, the particle size of carbon black used was approximately 30 μm. A detonation experiment was conducted using the above explosive sample. The method for carrying out this test is to prepare the explosive sample using the material shown in Figure 2.
Cu, 6.2mm inner diameter, 6.7mm outer diameter detonator tube body, 22mm length
I set it up and loaded it. In this case, when the specific gravity is 1.15, the drug amount is 0.74 g, and when the specific gravity is 1.40, the drug amount is 0.9 g. As shown in Figure 3, the optical fiber was fixed in contact with the drug surface using an optical fiber fixing plug made of Al material, and the detonator body containing the explosive sample was fixed using the detonator mounting plug. . A multimode optical fiber made of quartz with a core diameter of 0.8 mm and an attenuation rate of 6 dB/Km was used to guide the laser beam from the laser oscillator to the explosive surface. Also, the wavelength of laser light is
1.06μm YAG laser, pulse width 0.2~
We used a device with variable energy of 9 ms and energy in the range of 0.1 to 40.5 J. The results of the experiment are shown in Table 1. Examples 21-23 Using explosives shown in Table 1 instead of PETN,
Experiments were conducted in the same manner as in Examples 1 to 20, except that the additives shown in Table 1 were used in place of carbon black. The results are shown in Table 1. Comparative Examples 1 to 4 Examples 1 to 4 except that carbon black was not added
Samples were prepared in the same manner as in 20. Experiments similar to those in Examples were conducted using these samples. The results are shown in Table 1. Comparative Examples 5 to 7 First regarding specific gravity and amount of laser light absorbing substance added
Samples of explosives outside the range specified by the present invention as shown in the table were prepared in the same manner as in the Examples, and the same tests as in the Examples were conducted. The results are shown in Table 1.

【table】

[Table] Next, the test results of each comparative example and example will be explained in detail. In Examples 1 to 20, as a general tendency, as long as the amount of carbon black added is the same, the lower the specific gravity, the lower the minimum ignition energy of the laser is required, and the minimum detonation energy of the laser is about the same for specific gravity of 1.10 and 1.15. Furthermore, with the same specific gravity, carbon black added in an amount of about 1.0 to 2.0% could be detonated with a small amount of laser energy. Examples 21 to 23 were also able to complete the explosive test. In the case of PETN alone in Comparative Examples 1 to 4, complete explosion was not possible even with the laser irradiation energy of 40.5 J, which is the maximum value that can be generated by the oscillator in this experiment.
Those with specific gravity of 1.10 and 1.15 were semi-explosive, and those with specific gravity of 1.20 and 1.40 were non-explosive. This is thought to be because PETN alone is white and cannot absorb the laser light and reflects most of it, so the thermal energy of the laser light is not effectively transmitted to the explosive. In Comparative Examples 5 and 6, the specific gravity was within the range specified by the present invention, but the amount of carbon black added was outside the range specified by the present invention, and the laser energy of 40.5 J was half-explosion. In Comparative Example 7, the amount of carbon black added was within the range, but the specific gravity was outside the range.
It was 40.5J and non-explosive. From the above examples and comparative examples, it has been demonstrated that the detonation method of the present invention can detonate a secondary explosive using a normal pulsed laser beam having a pulse width on the order of milliseconds.

[Brief explanation of the drawing]

Figure 1 shows the output characteristics of laser light in normal pulse oscillation and Q-switch oscillation methods.
The figure shows a container loaded with an explosive sample in the example, and FIG. 3 is a diagram showing a method of fixing the container loaded with the explosive sample used in the example and fixing the optical fiber.

Claims (1)

[Scope of Claims] 1. A method of irradiating an explosive containing a laser light absorbing substance with a laser beam to detonate the explosive, comprising: one or more secondary particles selected from the group consisting of pensrite, tetryl, and hexogen; 0.5 to 10% by weight of one or more laser light absorbing substances selected from the group consisting of carbon black, graphite, and black dye is added to the explosive, and the specific gravity is adjusted to 1.1 to 1.4. ~11μm,
A method of detonating explosives using laser light, which is characterized by irradiating laser light with a pulse width of 0.1 to 10 ms.