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ОБРАЗОВАНИЯ ДЕФЕКТОВ В TlInS2 ГЕКСАГОНАЛЬНОЙ МОДИФИКАЦИИ ОБЛУЧЕННЫХ γ-КВАНТАМИ
Р.С.Мадатов, М.А.Мамедов, М.А.Мехрабова, Н.М.Зейналов
Институт Радиационных Проблем НАНА
Кристаллы относятся к семейству слоистых полупроводников . В структуре гексагональной модификации (ГМ) между тригональными призмами находятся октаэдры. Основу этой структуры составляет четырехслойная анионная упаковка. Тригональные призмы заполнены атомами , а октаэдры атомами .

Известно, что ГМ- имеет более плотную упаковку, чем другие модификации . Поэтому ГМ- более радиационно устойчивые, чем другие модификации.

В данной работе анализируется образования дефектов в ГМ- и взаимодействие радиационных дефектов с дефектами структуры. На основе вычисленных пороговой энергии и энергии смещения [1] для атомов ГМ- и измеренных электрических и фотоэлектрических параметров объясняется дефектообразования в этих кристаллах. Определено, что для разрыва связи In-S и перевода атома серы в междоузельное положение необходима пороговая энергия =11,82 эВ, а для перевода атома индия в междоузельное положение необходима пороговая энергия =16,9 эВ. Также определено, что энергия смещения для атома серы =302,9 кэВ, а для смещения атома индия =571 кэВ. По этим данным можно предполагать, что при облучении ГМ- γ-квантами могут смещаться в основном атомы серы. По электрическим и фотоэлектрическим данным можно прийти к выводу, что при малых дозах происходит накопление радиационных дефектов в кристалле. При увеличении дозы облучения вследствие взаимодействия радиационных дефектов с исходными неоднородностями происходит образование сложных дефектов [2], в частности увеличивается концентрация неравновесных носителей заряда. В результате электропроводность увеличивается. Образованные структурные дефекты, ионы, неравновесные носители и другие факторы изменяют взаимодействие между дефектами. В результате эти факторы определяют эффективность таких процессов, как диффузия точечных дефектов, отжиг дефектных комплексов, перестройка дефектных комплексов и др.

Таким образом, на основе исследованных электрических и фотоэлектрических свойств установлены природа дефектов, механизм переноса носителей заряда, концентрация глубоких уровней. Получено, что за счет γ-облучения можно целенаправленно управлять проводимостью монокристалла ГМ-. Это дает возможность для использования этих материалов в качестве радиационностойких материалов.


Литература
1.Р.С.Мадатов, М.А.Мехрабова, М.А.Мамедов. Влияние γ-излучения на электрические параметры монокристалла .7-я международная конференция ,Ядерная и радиационная физика, 8-11 сениябр 2009 г.,Алматы, Казахстан,с. 74.

2. Под ред. Л.С.Смирнова, Физические процессы в облученных полупроводниках, Изд. «Наука», Новосибирск, 1977.



PROVISION OF RADIATION SAFETY AND NUCLEAR SECURITY IN AZERBAIJAN REPUBLIC
A.A.Qaribov, R.N.Mehdiyeva

Institute of Radiation Problems of ANAS

ravan.m.n.@rambler.ru


  • Objective:

  • To show the necessity of providing Radiation Safety and Nuclear Security in Azerbaijan Republic and to determine the ways of their provision

  • Goal:

  • In order to provide Radiation Safety and Nuclear Security to determine the situation in Azerbaijan Republic from this aspect, fight against the harmful sources and means, predict the unexpected accidents and develop proper proposals.

  • Justification:

  • Azerbaijan Republic has not yet any nuclear technology. However, Azerbaijan is bordered by the countries which have nuclear technology, nuclear reactor and weapons as well as an effort for terrorism, obtaining nuclear weapons. That’s why Nuclear Security of Azerbaijan Republic is characterized with external factors. The external factors threatening Radiation Safety and Nuclear Security of Azerbaijan

Republic are approximately divided into the following groups:

  • 1. Nuclear equipment and different reactors located in European part of Russia

  • 2. Technological equipment for nuclear material in Kazakhstan

  • The double-purpose nuclear reactor with high-speed neutrons with vapor and pollution output in Aktau (Kazakhstan). This reactor has been exploited for more than 25 years. Thus, the reactors located near Azerbaijan borders have been using for 25-30 years and they have high risk of accident.

  • 3. Armenian Nuclear Power Plant-presently there is WWER type reactor with power 315 MVt. The total operation period of the reactor is more than 20 years and probability of accident is high.

  • 4. The operation of research nuclear reactor was stopped in Georgia. But the complete liquidation of its operation is a process requiring a long time.

  • 5. WWER-1000 nuclear reactor is under construction in Iran (Busher)

  • Influences of wastes and spills by neighboring countries during accidents in the nuclear installations;

  • Nuclear weapons’ test: 1960-1980

  • Concentration of the radionuclides Sr-90 and Cs-137 in soil has changed

  • After the Chernobyl accident activity of the radionuclides Sr-90 and Cs-137 has increased for 2 times.

  • Transboundary radioactive spills into the Caspian Sea from Russia by the rivers of Volga and the Urals and other countries cause some changes in the Caspian Sea.

  • Transportation of nuclear materials to Azerbaijan Republic for terror purpose.

  • According to its geopolitical location the Republic of Azerbaijan is situated at the intersection of haulways leading from East to West and from North to South and serve as a peculiar “bridge” joining these parts of the world. The volume of transit cargoes transported across the territory of the country increase year by year and in this meaning adoption of the Statute “About Export Control” by Parliament on December 29, 2005 as well as the decision of the Cabinet of Ministers on implementation of the Statute is an original instrument to provide and strengthen international measures on nonproliferation of weapons of mass destruction and fight against international terrorism.

  • It is necessary to mention that the volume of freights transported across Azerbaijan sector of the traffic route Europe-Caucasus-Asia has increased for 1.5 times for the last 5 years and reached 41.6 million tonnes. The volume of freights increased for 13,2% in 2008 in comparison with 2007.

  • According to statistical data of State Statistics Committee the volume of freights transported across this traffic route constitutes 33.6% of all freights in the country, besides, 57.4% of the freights was transported by rail trains, 28.4% - by motor and 14.2%-by sea transport.

  • 41,6 million tonnes of the transported freights was composed of transit cargoes. Besides, 21.7% freights by rail trains and 87.1% freights by sea transport fall to the share of transit cargoes

  • Consequently, these statistical data show that strategically geographical location of Azerbaijan Republic makes its traffic route and it may be used both for illicit trafficking of weapons of mass destruction and corresponding cargoes. The reinforcement of export control and transit is needed for these kinds of items and prevention of illicit trafficking requires awareness and specialized knowledge among the representatives of power structures.

  • Nuclear and radioactive materials may be transported across Azerbaijan Republic from the neighboring countries’ nuclear installations by water, air and land. Here naturally contraband import and transit transportation can be mentioned. Before the assessment of nuclear and radiation harm risks by the above mentioned sources and means, the current situation should be studied.

  • Obviously, the realization of export control should protect national security, political, military and economic interests of Azerbaijan Republic.


The bodies of executive power performing the export control in accordance with the nomenclature of the products qualifying an export control are the followings:

  • The Cabinet of Ministers of Azerbaijan Republic;

  • The Ministry of Emergency Situations;

  • The Ministry of Ecology and Natural Resources;

  • The Ministry of Industry and Energy;

  • The Ministry of Health;

  • The Ministry of National Security;

  • The Ministry of Internal Affairs;

  • State Border Service (within the framework of its authority)

  • The Ministry of Agriculture;

  • National Academy of Sciences

  • The Ministry of Communication and Information Technologies (within the framework of its authority)

  • The Special State Protection Service (on protected items);

  • The Ministry of Defense;

  • The Ministry of Transport;

  • The Ministry of Defense Industry;

  • Agency of Author’s Rights.

  • It should be mentioned that the control on the export of the products which can be used in production of weapons of mass destruction and others or relate to nuclear energy is performed in account of fulfilling the responsibilities abiding the intergovernmental international agreements which Azerbaijan has joined.

  • Corresponding to the current legislation the control on the transportation of the products qualifying export control across the state border and customs territory of Azerbaijan Republic is performed by border and customs authorities of Azerbaijan Republic. However, the lack of sufficient practice and knowledge among the representatives of authority structures on the problems of weapons of mass destruction makes a favorable condition for illicit trafficking of such kinds of items. Consequently, it’s necessary to raise the level of awareness of the representatives of authority structures in the field of nonproliferation, export control and identification of products. Apparently, in order to provide an efficient activity of the export control system among state authorities participating in export control it’s important to establish a special cooperation. There’s a great necessity for providing corresponding coordinated efforts among the organizations involved in the realization of export control

  • Azerbaijan Republic has a collection of fundamental laws being in power in the field of the use of nuclear energy. Law on Radiation Safety of the Population was adopted on December 30, 1997. The law puts a requirement in front of Industrial Safety and Mining Supervision State Agency at the Ministries of Health, Ecology and Natural Resources and Emergency Situations as the main regulatory authority of all nuclear and radiation activities in Azerbaijan. Special cases are regulated in correspondence with The Criminal Code adopted in 2000 according to the Decree № 758 introduced by the President in 1998 and governmental support, Administrative Code, The Health Safety Law of 1999, and The Technical Safety Law of 1999, The Civil Code Law of 1998.

  • The norms and standards which have been comprehensively developed in the former Soviet Union and Russia are used in Azerbaijan. They include safety norms, specifications of 1996 on the processing of radioactive wastes, General Safety Norms and so on.

  • The norms and standards designed for the Radiation Safety of the Population are currently being developed in accordance with the international practice and warranties of IAEA.

  • In order to provide the effective realization of the measures keeping international standards in the field of Nuclear and Radiological activities and regulating these functions an independent regulatory authority- Nuclear and Radiological Activity Regulations State Agency was created at the Ministry of Emergency Situations, introduced by the Decree of the President of Azerbaijan Republic on April 24, 2008 and the Statute of the Agency was approved by the President of Azerbaijan in accordance with the decree introduced on April 3, 2009.


The main activity directions of the Agency are the followings:

  • participates in pursuing unique state policy in the field of nuclear and radiological activities within the framework of its authorities and provides the realization of this policy;

  • determines the mechanism of nuclear and radiological activity safety regulation;

  • controls nuclear and radiological activity realization and safety provision;

  • takes measures against the violations detected in the field of Nuclear Security and Radiation Safety provision within the framework of the legislation;

  • controls the observation of the norms and laws in the field of Nuclear Security and Radiation Safety provision;

  • Other directions designated within the framework of the legislation.


The duties of the Agency:

  • - make a report on the import, export, re-export, re-import and transportation of the technologies and “program provision” for the preparation, manufacturing and use of nuclear materials, technologies, devices, equipments, radioactive ionizing radiation sources, as well as radioactive wastes and isotope products (radioactive and artificially-obtained isotopes) and all other items of this category;

  • - participate in the provision of radiation safety of the population and the territory and in the radioecological monitoring of environment within its authorities;

  • - require taking necessary measures in order to prevent the violations detected in the field of Radiation Safety and Nuclear Security and provide radiation safety at the enterprises and organizations using ionizing radiation sources;

  • - make a report to the Ministry of Emergency Situations on providing the activities of solving radiation-concerned problems with special permissions and other qualifying documents within the framework of the legislation and laws;

  • -provide the transport means containing radioactive sources as well as used for the transportation of radioactive sources and wastes with qualifying documents within the framework of the legislation;

  • -take corresponding measures in cases of non-observation and violation of the regulations of the legislation on nuclear and radiological activities;

  • -improve the control system on the circulation of nuclear and radioactive materials and ionizing radiation sources, establish its database and carry out its registration;

  • - connect the activities of other authorities in the field of nuclear and radiological activity;

  • - make operative decisions in the field of nuclear and radiological activity;

  • - control the circulation of radioactive sources within the framework of the legislation.



The rights of the Agency are:

  • have a free entrance right into the installations not depending on their property forms in order to check the safety of nuclear and radioactive materials, ionizing radiation sources and the observation of Physical Security Law within the authorities of the Agency;

  • make urgent decisions about the installations of nuclear and radiation danger, enterprises, departments and organizations of ionizing radiation sources within the authorities of the Agency;

  • Cooperate and exchange practice with international organizations, corresponding governmental organizations of foreign countries within the responsibilities of the Agency.

  • We hope that the illicit trafficking of nuclear materials will be prevented in the territory of Azerbaijan Republic due to the activity of the Agency by provision of border check points with technical equipments and fighting against corruption in these organizations.

  • An International Convention for the Suppression of Acts of Nuclear Terrorism (“Nuclear Terrorism Convention”) adopted in April 13, 2005 by General Assembly of UNO was approved as a law in accordance with the Decree introduced by the President of Azerbaijan Republic on January 19, 2009. As the main direction of the policy of Azerbaijan Republic is the protection of international peace and security, development of friendly relations among nations, the peaceful use of nuclear energy and corporation while signing the convention we stated that our republic has no power to provide the implementation of the regulations of the convention in the territories occupied by Armenia until those areas become free. The Nagorny Karabagh and its neighbor areas are completely out of control and the illicit trafficking of nuclear materials across these areas is inevitable.



INTERNATIONAL RADIATION PROTECTION STANDARDS
Jalal Aslan Aghayev

Institute of Radiation Problems ANAS

j.aghayev@yahoo.com
Today the recommendations of ICRP have a profound influence on radiation protection all over the world. The latest recommendations were issued as publication no. 60 (ICRP 60 1991). This docu­ment elaborated a conceptual framework for radiation protection based on ethics, experimental work, and risk assessment. An important presumption of the ICRP conceptual framework is that even small doses of radiation may produce some deleterious effects. The three main principles of the ICRP for proposed or continuing radiation-protection practices are:

a) The justification principle

b) The optimization principle

c) The dose-limitation principle.

The justification principle prohibits practices involving additional radiation exposures unless they produce sufficient societal benefits. The optimization principle requires managers to keep radiation exposures as low as reasonably achievable (ALARA), taking into account economic and social fac­tors. The dose-limitation principle limits exposure of individuals to radiation. Because medical expo­sures are intended to be as low as possible and to provide a direct benefit to the patient, ICRP recom­mends in publication 60 that no one apply dose limits to medical exposures. As part of the process of justifying radiation exposures, the ICRP also implicitly uses the "substitution principle." For exam­ple, in medical diagnoses of pregnant women offspring, the ICRP recommends use of ultrasound rather than X-rays.

The system of radiological protection recommended by ICRP for intervention is based on two addi­tional principles:

d) The proposed intervention should do more good than harm,

e) One should optimize the form, scale, and duration of intervention.

Although the ICRP does not employ the term "precautionary principle," it does use the concept, at least implicitly. In fact, the whole philosophy of protection against stochastic effects is based not on proved harm from radiation, because hereditary damage from radiation has never been demonstrated conclusively, either in humans or at low doses. Rather, the ICRP and other agencies believe that adopting the linear, no-threshold hypothesis is reasonable, if one wishes to take ethical precautions in a situation of uncertainty. This hypothesis is, however, now being challenged by the Health Physics Society. The society states that quantitative risk assessment below individual doses of 50mSv (5 rem) per year or 100 mSv (10 rem) lifetime should be avoided because of insufficient epi­demiological data about health risks at such low exposure levels.

On 15 June, 1995 the Board of Governors of the IAEA adopted safety fundamentals relating to radia­tion protection and the safety of radiation sources (IAEA 1996b). These fundamentals are mainly ethical, and they are partly based on the protection principles given in ICRP publication 60 (ICRP 60 1991). According to (IAEA 1996b) the primary aim of radiation protection is to provide appropriate standards of protection and safety for humans without either unduly limiting the benefits of practices giving rise to radiation exposure or incurring disproportionate costs in the case of intervention. This aim is expressed by two specific protection and safety objectives:



Protection Objective: to prevent the occurrence of deterministic effects in individuals by keeping the doses below the relevant threshold and to ensure that all reasonable steps are taken to reduce the oc­currence of stochastic effects in the population at present and in the future.

Safety Objective: to protect individuals, society and the environment from harm by establishing and maintaining effective defenses against radiological hazards from sources.

These objectives are achieved by the application of the following eleven principles:

1. A practice shall be justified on the grounds that it produces sufficient benefit to the exposed individual(s) and to society to offset the radiation detriment it may cause.

2. For justified practices, other than those involving medical exposures, restrictions on the dose that individuals may incur (dose limits) are required in order to ensure that no person be subject to an un­acceptable risk attributable to radiation.

3. For any source, except for therapeutic medical exposure, the doses, the number of people exposed, and the likelihood of incurring exposures should all be kept as low as reasonably achievable.

4. All reasonably practicable measures shall be taken to enhance operational safety and to prevent radiation accidents and mitigate their consequences, should they occur.

5. Any proposed intervention shall do more good than harm.

6. The form, scale, and duration of any intervention shall be optimized so that the net benefit is maxi­mized.

7. Sources shall be located, taking into account those factors, which affect exposure, or potential ex­posure, of individuals and populations.

8. The design and construction of nuclear facilities shall ensure that a source is suited for reliable, stable and easily manageable operation that ensures protection and safety. For this purpose, consid­eration must be given to defense in depth, human factors, system testing, and feedback of operational experience.

9. The operation and use of sources shall be based upon procedures and conditions of operation, which promote safety, and security of the source, optimization of radiation protection, and which re­flect the lessons learned from operational experience.

10. The government shall establish a legal framework for regulation of practices and interventions, with clear allocation of responsibilities, including those of a Regulatory Authority.

11. Parties responsible under the legal framework shall, as appropriate, provide for radiation protec­tion and safety, verify its effectiveness, and prepare adequate emergency plans.






THE ROLE OF SCIENTIFIC INSTITUTIONS IN COMBATING ILLICIT TRAFFICKING OF NUCLEAR AND OTHER RADIOACTIVE MATERIALS IN THE REPUBLIC OF AZERBAIJAN

Gabulov Ibrahim Akram



Institute of Radiation Problems ANAS




gabulov@azdata.net; ibrahim_gabulov@yahoo.com



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