| Start of section
Production, amateur Radio amateurs Aircraft model, rocket-model Useful, entertaining |
Stealth Master
Electronics Physics Technologies Inventions |
Secrets of the cosmos
Secrets of the Earth Secrets of the Ocean Tricks Map of section |
  |
| Use of the site materials is allowed subject to the link (for websites - hyperlinks) | |||
Navigation: => |
Home / Technology market / Current inventions and models / Back / |
|
INVENTION
Patent of the Russian Federation RU2104770
METHOD OF IRRADIATION OF MINERALS
Applicant's name: Petersburg Institute of Nuclear Physics named after BP Konstantinov RAS; Konoplev Kir Alexandrovich; Orlov Sergey Petrovich; Dmgh Chmishkyan
The name of the inventor: Konoplev KA ; Orlov, SP; Chmishkyan D.V.
The name of the patent holder: Petersburg Institute of Nuclear Physics named after BP Konstantinov RAS; Konoplev Kir Alexandrovich; Orlov Sergey Petrovich; Dmgh Chmishkyan
Address for correspondence: Petersburg Institute of Nuclear Physics named after BP Konstantinov RAS; Konoplev Kir Alexandrovich; Orlov Sergey Petrovich; Dmgh Chmishkyan
Date of commencement of the patent: 1996.06.04
The invention relates to radiation methods for processing minerals in order to enhance their jewelry value. The proposed method makes it possible to reduce the induced activity of the samples caused by thermal and resonant neutrons, which are formed in the working volume by slowing down fast neutrons. SUMMARY OF THE INVENTION: thermal neutrons are partially filtered by a cadmium foil wrapped around a container. The container is filled with a substance or a mixture of substances that absorb thermal and resonant neutrons, for example boron, cadmium, boron indium, cadmium-tantalum, cadmium-indium, etc. Then, the minerals are placed therein, the ratio of the proposed substances in the mixture and the filling density of the container being calculated from the condition that, at the time of irradiation in the container, the ratio of the fast neutron flux to the thermal neutron flux is greater than or equal to 10.
DESCRIPTION OF THE INVENTION
The invention relates to radiation methods for treating minerals in order to change their color, eliminate defects, etc. (In order to increase their jewelry value).
A method is known for treating minerals and precious stones using accelerated electrons with an energy of 3 to 45 MeV with an integral dose of 1 × 10 16 to 1 × 10 18 electron / cm 2 at a temperature of 80 ° C to 350 ° C (DE, N 2910520 , Cl. C 04 B 41/00, 1982).
A method for changing the color of minerals in a reactor by the action of a neutron and its associated gamma radiation is known. The irradiation is carried out by fast neutrons with an energy of not less than 0.5 MeV with an integral irradiation dose of 5 · 10 15 - 1 · 10 18 neutrons / cm 2 and at an integrated dose of gamma irradiation of 5 × 10 6 -1 · 10 9 x-rays at a temperature of no higher than 300 ° C. As the thermal neutron filter, cadmium foil is used (DE, No. 2934944, class C 04B 41/00, 1982) .
A method for irradiating minerals in a reactor in a fast neutron flux with an energy of not less than 0.5 MeV is also known with an integral dose of 5 × 10 15 -1 1 × 10 18 and an integrated dose of gamma radiation of 5 × 10 5 -1 × 10 9 x-ray. The thermal neutrons present in the nuclear reactor flow spectrum are filtered with cadmium foil (NL, No. 172467, class C 30 B 33/00, 1987) .
The method closest to the claimed method is the irradiation of minerals with neutron and gamma radiation from the reactor (SU, No. 601855, class B 01 J 19/08, 1983). The method consists in using fast neutrons with an energy of not less than 2 MeV in the integral fluxes of neutron radiation 5 · 10 15 - 5 · 10 18 neutrons / cm 2 and integral doses of gamma radiation 5 · 10 6 - 5 to optimize the characteristics of the resulting product · 10 9 X-ray. Thermal neutrons were partially filtered by cadmium foil, the color of minerals irradiated in this way proved to be resistant to light and thermal effects.
However, all the methods described above require a long flash to eliminate the induced activity.
The inventive method allows reducing the induced activity of the samples due to thermal and resonant neutrons produced by slowing down fast neutrons in the working volume. To this end, in the method for irradiating minerals in the reactor neutron flux, when thermal neutrons are partially filtered by means of cadmium foil, the following is proposed in accordance with the claimed invention.
The container (or container) containing the irradiated minerals is filled with a substance or a mixture of substances absorbing thermal and resonant neutrons, for example boron indium, cadmium-tantalum, cadmium-indium, the ratio of these substances in the mixture and the filling density of the container is calculated as In the manner that at the time of irradiation in a container, the condition 
Where Φ b.s. - a stream of fast neutrons with energy above 1 MeV;
The so-called. - thermal neutron flux.
Such a set of traits, as established experimentally, can reduce the induced activity after a two-week exposure to 
74 Bq / g, which according to IAEA standards does not represent a radiation hazard.
Since the materials usually contain activated impurities and their induced activity is proportional to the flux of thermal neutrons, and to obtain the desired color of the mineral, it is necessary to irradiate them with a fluence of fast neutrons of not less than 10 18 n / cm 2 , because In the nuclear reactor, the ratio of fast neutrons to thermal neutrons 1, the minerals under such irradiation will receive the same fluence of thermal neutrons, which leads to induced activity 1000 Bq / g, which is not permissible. The irradiated container with minerals has a certain volume, and its shielding by thermal neutron absorbing material, for example cadmium as a thermal neutron filter (which is used in the analogs and prototype discussed above), does not provide the necessary ratio between fast and thermal neutrons due to the generation of thermal neutrons inside the container Due to the slowing down of fast neutrons.
It was experimentally established that the ratio of the fast neutron flux to the thermal neutron flux inside the container at the time of irradiation at which various defects in minerals are eliminated, their coloring is improved, and the induced activity decreases by an order of magnitude. For this purpose, known absorbers of thermal and resonant neutrons, for example boron, indium, tantalum, etc., as well as mixtures thereof, can be used.
The density of filling the container with absorbing substances is calculated in each specific case (based on the weight of the minerals of the neutron flux at the site of irradiation, etc.), but the condition must be met that in the container at the time of irradiation
The possibility of implementing the method is confirmed by the following examples.
1. Topazes were placed in a 100 cc container, screened with cadmium, filled with 185 g minerals and 20 g boron carbide (p = 0.2 g / cm 3 ). This, according to calculations, provides in the container, at the time of irradiation, the ratio of the Ph. / Ph.D. = 12. The container was irradiated in the channel of the reactor, for 15 hours of neutron fluence irradiation (with energy above 1 MeV) was 3.9 × 10 18 n / cm 2 . After a two-week exposure, the activity of topaz was 47 Bq / g. After irradiation, the minerals acquired a dark blue color.
2. Topazes were placed in a 100 cc container, screened with cadmium, filled with 185 g of minerals, 20 g indium and 20 g boron carbide. This, according to calculations, provides in the container, at the time of irradiation, the ratio of the Ph. / Ph.D. = 25. The container was irradiated to a neutron fluence (with energy above 1 MeV) of 2.7 × 10 18 n / cm 2 . After a two-week exposure, the activity of topaz was 8 Bq / g. After irradiation, the minerals acquired a dark blue color.
CLAIM
A method for irradiating minerals in the neutron flux of a reactor in a container, characterized in that a substance or a mixture of substances containing elements absorbing thermal and resonant neutrons is placed in a container in which the irradiated minerals are placed, the ratio of these substances and the density of filling of the container calculated , That at the moment of irradiation of minerals in the container, the ratio of the fast neutron flux to the thermal neutron flux should be greater than or equal to 10.
print version
Date of publication 03.01.2007gg
Comments
When commenting on, remember that the content and tone of your message can hurt the feelings of real people, show respect and tolerance to your interlocutors even if you do not share their opinion, your behavior in the conditions of freedom of expression and anonymity provided by the Internet, changes Not only virtual, but also the real world. All comments are hidden from the index, spam is controlled.