Answer from Yovetlana Zemtsova[newbie]
Proton radiation is radiation consisting of a stream of protons (see Atom). Proton radiation is the main component of cosmic radiation (see). Under terrestrial conditions, protons of various energies are produced in charged particle accelerators (see). Being positively charged particles, protons, when passing through matter, interact with the negatively charged electrons of atoms and tear them out of their electron shells. As a result, ionization (see Ionizing radiation) of the atoms of the substance occurs. The ionization density by protons increases sharply at the end of the particle path. Due to this property, protons are convenient to use in radiation therapy (see Proton therapy) for selective irradiation of deep-seated tumors (for example, the pituitary gland). High-energy protons have a small scattering angle, which also contributes to dose localization in one place. High-energy protons, overcoming Coulomb repulsion, enter the nucleus and cause various nuclear reactions, which result in the formation of secondary radiation - neutron, gamma radiation, etc. In this regard, when a substance is irradiated with high-energy protons, ionization of the medium occurs not only due to primary protons; but also due to secondary radiation. This circumstance must be taken into account when calculating doses created by proton radiation.
Proton radiation is a stream of positively charged nuclear particles - protons. Proton radiation was first discovered in 1886 in the form of so-called channel rays in discharge tubes.
Sources of intense proton radiation are charged particle accelerators (see). With the help of accelerators, beams of P. and. with an energy of tens of billions of electron volts. Even greater energies of P. and. found in outer space. P. and. is the main component of galactic and solar cosmic radiation. Intense flows of P. and. discovered in near-Earth space - in the so-called radiation belts of the Earth.
P.'s ability and. penetrate through layers of matter depends on the energy of the proton beam (see) and the properties of the substance. P. and. with an energy of 10 MeV can pass through a layer of air (at normal temperature and pressure) of about 1 m. With increasing energy, P. and. up to 1000 MeV, the thickness of the layer increases to almost 3 km.
In heavy substances, P. is retained in thinner layers. So, in lead P. and. with an energy of 10 MeV it travels about 1/3 mm, and with an energy of 1000 MeV - slightly less than 60 cm. Proton radiation with an energy above 100 MeV can penetrate a body to a depth of 10 cm or more. The biological effect of proton radiation with an energy of hundreds of megaelectron volts during acute irradiation is generally similar to the effect of x-ray and gamma radiation.
At the same time, the biological effect of protons of such energies has some features compared to X-ray and gamma radiation (less distinct reaction from the hematopoietic organs in the early stages, greater severity of hemorrhagic syndrome, etc.). At relatively low energies, the biological effectiveness of P. and. higher than X-ray and gamma radiation. This is due to the higher ionizing ability of such protons. Unlike X-rays and gamma rays, protons passing through biological tissue are capable of producing nuclear reactions. As a result of nuclear reactions, secondary particles are formed that have a high ionizing ability, which leads to the absorption of a relatively large amount of energy in a small volume of tissue and to corresponding local tissue damage. This circumstance may be due to the greater blastomogenic effect of P. and. compared to x-rays and gamma radiation.
To protect against proton radiation, substances are used that effectively inhibit protons and form relatively few secondary particles during nuclear interactions

Penetrating radiation is a stream of gamma rays and neutrons emitted from the area of ​​a nuclear explosion.

The sources of penetrating radiation are nuclear reactions and radioactive decay of the products of a nuclear explosion.

The duration of action of penetrating radiation does not exceed 10-15 sec since the explosion. During this time, the decay of short-lived fission fragments formed as a result of a nuclear reaction ends. In addition, the radioactive cloud rises to a great height and radioactive radiation is absorbed by the air without reaching the earth's surface.

Penetrating radiation is characterized radiation dose , i.e., the amount of radioactive radiation energy absorbed per unit volume of the irradiated environment. The radiation dose quantitatively characterizes the ionization that fluxes of gamma rays and neutrons can produce in an air volume.

The ionization process consists of “knocking out” electrons from the electron shell of atoms. As a result, electrically neutral atoms turn into differently charged particles - ions.

Penetrating radiation is the sum of gamma radiation and neutron doses.

Gamma radiation , constituting the bulk of penetrating radiation, it occurs both directly at the moment of explosion in the process of an explosive nuclear reaction, and after the explosion as a result of radioactive capture of neutrons by the nuclei of atoms of various elements. The effect of gamma radiation lasts 10-15 sec.

The unit for measuring the dose of gamma ray radiation is the X-ray special international physical unit of dose (amount of energy).

X-ray - This is the amount of gamma radiation that at a temperature of 0° and a pressure of 760 mm creates 2 billion ion pairs in 1 cm 3 of dry air (more precisely, 2.08-10 9). Denoted by the letter X-ray R. A thousandth of a roentgen is called a milliroentgen and is designated Mr.

Neutron flux , occurring during a nuclear explosion, contains fast and slow neutrons, which have different effects on living organisms. The share of neutrons in the total dose of penetrating radiation is less than the share of gamma rays. It increases slightly with decreasing power of a nuclear explosion.

The main source of neutrons in a nuclear explosion is a nuclear chain reaction. The neutron stream is emitted within a fraction of a second after the explosion and can cause artificial induced radiation in metal objects and soil. Induced radioactivity is observed only in the area immediately adjacent to the explosion site.

The radiation dose of a neutron flux is measured by a special unit - the biological equivalent of an x-ray.

Biological equivalent of an x-ray(BER) is a dose of neutrons, the biological effect of which is equivalent to the effect of 1 R gamma radiation.

The damaging effect of penetrating radiation on people is caused by irradiation , which has a harmful biological effect on living cells of the body. The essence of the damaging effect of penetrating radiation on living organisms is that gamma rays and neutrons ionize the molecules of living cells. This ionization disrupts the normal functioning of cells and, in large doses, leads to their death. Cells lose their ability to divide, causing a person to become ill with the so-called radiation sickness.

The damage to people by penetrating radiation depends on the magnitude of the radiation dose and the time during which this dose is received.

Single dose of radiation over four days up to 50 R, as well as the dose of systematic radiation - up to 100 R within ten days, does not cause external signs of disease and is considered safe. Radiation doses over 100 R cause radiation sickness.

Depending on the radiation dose, there are three degrees of radiation sickness: first (mild), second (moderate) and third (severe).

Radiation sickness first degree occurs at a total radiation dose of 100 - 200 R The latent period lasts two to three weeks, after which malaise, general weakness, nausea, dizziness, and periodic fever appear. The content of white blood cells in the blood decreases. First degree radiation sickness is curable.

Second degree radiation sickness occurs at a total exposure dose of 200 - 300 R. The latent period lasts about a week, after which the same signs of the disease appear as with radiation sickness of the first degree, but in a more pronounced form. With active treatment, recovery occurs within 1.5-2 months.

Radiation sickness of the third degree occurs at a total radiation dose of 300-500 R. The latent period is reduced to several hours. The disease progresses more intensely. With active treatment, recovery occurs within a few months.

Radiation dose over 500 R for humans it is usually considered fatal.

Doses of penetrating radiation depend on the type, power of the explosion and the distance from the center of the explosion. The values ​​of the radii at which different doses of penetrating radiation are possible during explosions of various powers are given in Table 8.

This is the widest range of the electromagnetic spectrum because it is not limited to high energies. Soft gamma radiation is produced during energy transitions inside atomic nuclei, while harder gamma radiation is produced during nuclear reactions. Gamma rays easily destroy molecules, including biological ones, but, fortunately, do not pass through the atmosphere. They can only be observed from space.

Ultra-high-energy gamma quanta are generated during the collision of charged particles accelerated by powerful electromagnetic fields of space objects or terrestrial particle accelerators. In the atmosphere, they destroy the nuclei of atoms, generating cascades of particles flying at near-light speed. When braking, these particles emit light, which is observed by special telescopes on Earth.

With energy above 10 14 eV avalanches of particles break through to the surface of the Earth. They are recorded by scintillation sensors. Where and how ultra-high-energy gamma rays are formed is not yet entirely clear. Such energies are inaccessible to earthly technologies. The most energetic quanta - 10 20 –10 21 eV, come from space extremely rarely - approximately one quantum per 100 years per square kilometer.

Sources

The image was taken in 2005 by the HESS gamma-ray telescope. It confirmed that supernova remnants serve as sources of cosmic rays - energetic charged particles that, interacting with matter, generate gamma radiation (see). The acceleration of particles is apparently provided by the powerful electromagnetic field of a compact object - a neutron star, which is formed at the site of an exploding supernova.

Collisions of energetic charged cosmic ray particles with atomic nuclei in the interstellar medium generate cascades of other particles, as well as gamma rays. This process is similar to cascades of particles in the earth's atmosphere that arise under the influence of cosmic rays (see). The origin of the highest energy cosmic rays is still being studied, but there is already evidence that they can be generated in supernova remnants.

Accretion disk around a supermassive black hole ( rice. artist)

During the evolution of large galaxies, supermassive black holes are formed in their centers, weighing from several million to billions of solar masses. They grow due to the accretion (fall) of interstellar matter and even entire stars onto the black hole.

During intense accretion, a rapidly rotating disk is formed around a black hole (due to the conservation of the angular momentum of the matter falling onto the hole). Due to the viscous friction of the layers rotating at different speeds, it heats up all the time and begins to emit in the X-ray range.

During accretion, part of the matter can be ejected in the form of jets along the axis of the rotating disk. This mechanism ensures the activity of galactic nuclei and quasars. There is also a black hole at the core of our Galaxy (Milky Way). Currently, its activity is minimal, but according to some signs, about 300 years ago it was much higher.

Receivers

Located in Namibia, it consists of 4 parabolic dishes with a diameter of 12 meters, placed on an area of ​​250 meters. Each of them has 382 round mirrors with a diameter of 60 cm, which concentrate bremsstrahlung, which occurs when energetic particles move in the atmosphere (see diagram of the telescope).

The telescope began operating in 2002. It can equally be used to register energetic gamma rays and charged particles - cosmic rays. One of its main results was direct confirmation of the long-standing assumption that the remnants of supernova explosions are sources of cosmic rays.

When an energetic gamma ray enters the atmosphere, it collides with the nucleus of one of the atoms and destroys it. In this case, several fragments of the atomic nucleus and gamma quanta of lower energy are generated, which, according to the law of conservation of momentum, move almost in the same direction as the original gamma quantum. These fragments and quanta soon collide with other nuclei, forming an avalanche of particles in the atmosphere.

Most of these particles travel faster than the speed of light in air. As a result, the particles emit bremsstrahlung, which reaches the Earth's surface and can be recorded by optical and ultraviolet telescopes. In fact, the earth's atmosphere itself serves as an element of the gamma-ray telescope. For ultra-high-energy gamma rays, the divergence of the beam reaching the Earth's surface is about 1 degree. This determines the resolution of the telescope.

At an even higher energy of gamma rays, an avalanche of particles itself reaches the surface - a wide air shower (EAS). They are recorded by scintillation sensors. In Argentina, the Pierre Auger Observatory (in honor of the discoverer of EAS) is currently being built to observe gamma rays and ultra-high-energy cosmic rays. It will include several thousand tanks of distilled water. The photomultipliers installed in them will monitor flashes that occur in water under the influence of energetic EAS particles.

An orbital observatory operating in the range from hard X-rays to soft gamma rays (from 15 keV to 10 MeV), was launched into orbit from the Baikonur Cosmodrome in 2002. The observatory was built by the European Space Agency (ESA) with the participation of Russia and the United States. The station's design uses the same platform as the previously launched (1999) European X-ray observatory XMM-Newton.

Electronic device for measuring weak fluxes of visible and ultraviolet radiation. A PMT is an electron tube with a photocathode and a set of electrodes, to which a successively increasing voltage is applied with a total difference of up to several kilovolts.

Radiation quanta fall on the photocathode and knock out electrons from it, which move to the first electrode, forming a weak photoelectric current. However, along the way, the electrons are accelerated by the applied voltage and knock out a significantly larger number of electrons from the electrode. This is repeated several times - according to the number of electrodes. As a result, the flow of electrons coming from the last electrode to the anode increases by several orders of magnitude compared to the initial photoelectric current. This makes it possible to register very weak light fluxes, down to individual quanta.

An important feature of PMTs is their response speed. This allows them to be used for recording transient phenomena, such as flashes that occur in a scintillator when an energetic charged particle or quantum is absorbed.

Installation file “Gamma Stream. Hydraulic calculation" is available upon request.

The software has a license agreement built into it.

In version 1.1.0.1 of the Gamma-Stream software package the following changes and additions have been made:

1. Section “Calculation of gas mass”:

1.1 The range of modules has been expanded:

• A 160L module has been added. at a pressure of 60 bar.
• Added 80L modules. and 100l. for a pressure of 150 bar with a 40mm diameter for Freon 23.
• A line of MPU-type modules for CO2 with a ZPU diameter of 12 mm has been introduced.

1.2. For GFFE Freon FK-5-1-12, two standard concentration values ​​have been introduced:

• regulatory concentration Сн 4.2% in accordance with the current edition of SP5.13130-2009 (amendment No. 1)
• normative concentration Сн 5.4% in accordance with the draft new edition SP5.13130 ​​as amended. 2015

1.3. Fixed display of the remaining GFFS in the pipework

2. Section “Hydraulic calculation”:

2.1. Special nozzles for GOTV Freon FK-5-1-12 were introduced

2.2. The coefficients of hydraulic resistance of pipeline elements (turn, tee) have been clarified

2.3. Additional losses in vertical sections of the pipeline have been clarified.

The Gamma Stream software can be used within 10 days from the date of installation in test mode without restriction of functionality. Next, you need to register to receive a Registration Key.

Registration algorithm:

1. In the “Registration Information” window, click on the “Get registration key” button.
2. In the “Gamma Stream Program User Registration” window that opens, fill in the data fields.

By clicking the “OK” button, you confirm the accuracy of the specified data and agree to the storage and processing of data by NPO Fire Automation Service LLC.
Next, the Program will generate a registration file and offer to save it to your computer.
To receive a registration key, you must send this file to our address. In a response letter we will send the key to the program.

Use of collected information.

We do not distribute the information received for any purpose, including transferring it to third parties. The information received from you can be disclosed only in cases stipulated by the legislation of the Russian Federation or at your written request.

FAQ

After analyzing frequently asked questions from designers, our specialists developed:

• file for calculating the maximum operating pressure for pipes with different wall thicknesses (xls, ~21Kb);
• file for calculating the opening area for releasing excess pressure (xls, ~62Kb).

1. Question: Why the program uses pipes and fittings that cannot be purchased on the market.
Answer:

• About pipes: a pipe assortment has been entered into the Gamma-Potok software database in accordance with GOST 8732 and GOST 8734. The report for the hydraulic calculation shows the RECOMMENDED types of pipes selected by the program. However, the user of the program can independently create his own custom list with a range of pipes, based on the possibility of purchasing it in his region. Also, when contacting us with the task of performing a hydraulic calculation, the designer can indicate the list of pipes he needs. To check the correct choice of pipe wall thickness, the designer can use the file “Calculation of the maximum operating pressure for pipes with different wall thicknesses” posted on our website.
• About fittings: The hydraulic calculation report shows the RECOMMENDED types of fittings selected by the program. The standard nomenclature of bends according to GOST 17375 and tees according to GOST 17376 is very limited and insufficient for performing design calculations. Therefore, an assortment of fittings has been introduced into the Gamma-Potok software database, which includes both a standard assortment of bends and tees in accordance with the specified GOST, and a size range of fittings (in increments of 1 mm in internal diameter), which can be manufactured individually in accordance with the requirements specified by GOST specialized enterprises. Also, the standards do not prohibit the use of fittings, which can be manufactured by installation organizations independently from pipes in accordance with GOST 8732 and GOST 8734.

2. Question: why does the Gamma Potok software not provide for the calculation of the opening area for releasing excess pressure in accordance with SP 5.13130.2009
Answer:

• We did not include this calculation in the hydraulic calculation program deliberately, because We believe that it is only indirectly related to hydraulic calculations and requires separate understanding and collection of initial data related to building structures.
• to help the designer perform this calculation independently, we have developed

Penetrating radiation. Penetrating radiation refers to the flow of gamma rays and neutrons emitted from the zone of a nuclear explosion into the external environment

Penetrating radiation refers to the flow of gamma rays and neutrons emitted from the zone of a nuclear explosion into the external environment. These types of radiation differ in their physical properties, but what they have in common is the ability to spread in the air in all directions over distances of up to 2.5-3 km. The duration of action of penetrating radiation is 15-20 seconds and is determined by the time the explosion cloud rises to such a height at which gamma radiation is completely absorbed by the air and does not reach the surface of the earth. It is necessary to distinguish between penetrating radiation, which lasts only a few seconds, and radioactive contamination of the area, the damaging effect of which persists for a long time. The main source of gamma radiation is fission fragments of nuclear fuel, located in the explosion zone and radioactive cloud. Neutrons during a nuclear explosion are formed during fission reactions (in the process of a chain reaction), during thermonuclear fusion, and also as a result of the decay of fission fragments. Neutrons produced during fission and fusion reactions are emitted within fractions of a microsecond and are called instant, and neutrons produced during the decay of fission fragments are lagging. Under the influence of neutrons, some non-radioactive substances become radioactive. This process is called induced activity.

Neutrons and gamma radiation act almost simultaneously. Although neutrons are emitted mainly in the first seconds, and gamma radiation lasts a few more seconds, this fact is not significant. In this connection, the damaging effect of penetrating radiation is determined by the total dose received from the addition of gamma radiation and neutron doses. So called neutron ammunition, are nuclear weapons with a low-power thermonuclear charge, characterized by an increased yield of neutron radiation. In neutron munitions, such damaging factors as shock waves, light radiation, and radioactive contamination of the area are of secondary importance, and the main damaging factor in the explosion of neutron munitions is penetrating radiation. In the composition of penetrating radiation in such ammunition, the neutron flux predominates over gamma radiation.

The damaging effect of penetrating radiation on people depends on the received radiation doses, i.e. on the amount of energy absorbed by the body and the associated degree of ionization of tissues. The result of exposure to various doses of radiation on a person is acute radiation sickness (ARS) .

For protection against penetrating radiation Various materials are used to attenuate the effects of gamma radiation and neutrons. This ability of materials is characterized by the value half attenuation layer . By this we mean the thickness of the material, passing through which the gamma radiation and neutron flux are attenuated by 2 times. It should be remembered that gamma radiation is attenuated the more, the denser the substance, for example, lead, concrete, steel. The neutron flux is more strongly attenuated by light materials (water, polyethylene, paraffin, fiberglass) containing nuclei of light elements such as hydrogen, carbon, etc. It is believed that a layer of water 70 cm thick or a layer of paraffin 650 cm weakens the neutron flux by 100 times ( Table 1).