Experimental investigation and practical use of hard cosmic rays ; Kietosios kosminės spinduliuolės eksperimentiniai tyrimai ir praktinis taikymas
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Ana USOVAIT Ė EXPERIMENTAL INVESTIGATION AND PRACTICAL USE OF HARD COSMIC RAYS Summary of Doctoral Dissertation Technological Sciences, Environmental Engineering and Landscape Management (04T) 1200 Vilnius 2005 VILNIUS GEDIMINAS TECHNICAL UNIVERSITY Ana USOVAIT Ė EXPERIMENTAL INVESTIGATION AND PRACTICAL USE OF HARD COSMIC RAYS Summary of Doctoral Dissertation Technological Sciences, Environmental Engineering and Landscape Management (04T) Vilnius 2005 Doctoral dissertation was prepared at Vilnius Gediminas Technical University in 2001 – 2005 Scientific Supervisor Prof Dr Habil Dmitrijus STYRO (Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering and Landscape Management – 04T) The Dissertation is being defended at the Council of Scientific Field of Environmental Engineering and Landscape Management at Vilnius Gediminas Technical University: Chairman Prof Dr Habil Donatas BUTKUS (Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering and Landscape Management – 04T) Members: Prof Dr Habil Gintautas Jurgis BABONAS (Semiconductor Physics Institute, Physical Sciences, Physics – 02P) Dr Habil Saulius VAIKASAS (Lithuanian University of Agriculture, Technological Sciences, EnvironmentalManagement – 04T) Assoc Prof Dr Aloyzas GIRGŽDYS (Vilnius Gediminas Technical University,
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| Publié par | vilnius_gediminas_technical_university |
| Publié le | 01 janvier 2006 |
| Nombre de lectures | 41 |
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Ana USOVAITĖ EXPERIMENTAL INVESTIGATION AND PRACTICAL USE OF HARD COSMIC RAYS Summary of Doctoral Dissertation Technological Sciences, Environmental Engineering and Landscape Management (04T)
Vilnius
2005
1200
VILNIUS GEDIMINAS TECHNICAL UNIVERSITY Ana USOVAITĖ EXPERIMENTAL INVESTIGATION AND PRACTICAL USE OF HARD COSMIC RAYS Summary of Doctoral Dissertation Technological Sciences, Environmental Engineering and Landscape Management (04T)
Vilnius
2005
Doctoral dissertation was prepared at Vilnius Gediminas Technical University in 2001 2005 Scientific Supervisor Prof Dr Habil Dmitrijus STYRO(Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering and Landscape Management 04T) The Dissertation is being defended at the Council of Scientific Field of Environmental Engineering and Landscape Management at Vilnius Gediminas Technical University: Chairman Prof Dr Habil Donatas BUTKUS (Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering and Landscape Management 04T) Members: Prof Dr Habil Gintautas Jurgis BABONAS (Semiconductor Physics Institute, Physical Sciences, Physics 02P) Dr Habil Saulius VAIKASAS University of Agriculture, (Lithuanian Technological Sciences, Environmental Engineering and Landscape Management 04T) Assoc Prof Dr Aloyzas GIRGDYS (Vilnius Gediminas Technical University, Technological Sciences, Environmental Engineering and Landscape Management 04T) Dr Dalia STASYTYTĖ-BUNEVIČIENĖ (Vilnius University Hospital Santarikiųklinikos, Biomedical Sciences, Societys Health 10B) Opponents: Assoc Prof Dr Saulius VASAREVIČIUS Gediminas Technical (Vilnius University, Technological Sciences, Environmental Engineering and Landscape Management 04T) Assoc Prof Dr Habil Konstancija JANKAUSKIENĖ(Kaunas University of Medicine, Biomedical Sciences, Societys Health 10B) The dissertation will be defended at the public meeting of the Council of Scientific Field of Environment Engineering and Landscape Management in the Senate Hall of Vilnius Gediminas Technical University at 2 p. m. on 19 December 2005. Address: Saulėtekio al. 11, LT-10223 Vilnius-40, Lithuania Tel.: +370 5 274 49 52, +370 5 274 49 56; fax +370 5 270 01 12; e-mail doktor@adm.vtu.lt The summary of the doctoral dissertation was distributed on 18 November 2005 A copy of the doctoral dissertation is available for review at the Library of Vilnius Gediminas Technical University (Saulėtekio al. 14, Vilnius, Lithuania) © Ana Usovaitė, 2005
VILNIAUS GEDIMINO TECHNIKOS UNIVERSITETAS Ana USOVAITĖ KIETOSIOS KOSMINĖS SPINDULIUOTĖS EKSPERIMENTINIAI TYRIMAI IR PRAKTINIS TAIKYMAS Daktaro disertacijos santrauka Technologijos mokslai, aplinkos ininerija ir kratotvarka (04T)
Vilnius
2005
Disertacija rengta 2001 2005 metais Vilniaus Gedimino technikos universitete. Mokslinis vadovas prof. habil. dr. Dmitrijus STYRO (Vilniaus Gedimino technikos universitetas, technologijos mokslai, aplinkos ininerija ir kratotvarka 04T). Disertacija ginama Vilniaus Gedimino technikos universiteto Aplinkos ininerijos ir kratotvarkos mokslo krypties taryboje: Pirmininkas prof. habil. dr. Donatas BUTKUS (Vilniaus Gedimino technikos universitetas, technologijos mokslai aplinkos ininerija ir kratotvarka 04T). Nariai: prof. habil. dr. Gintautas Jurgis BABONAS (Puslaidininkių fizikos institutas, fiziniai mokslai, fizika 02P), habil. dr. Saulius VAIKASAS (Lietuvos emėsūkio universitetas, technologijos mokslai, aplinkos ininerija ir kratotvarka 04T), doc. dr. Aloyzas GIRGDYS(Vilniaus Gedimino technikos universitetas, technologijos mokslai, aplinkos ininerija ir kratotvarka 04T), dr. Dalia STASYTYTĖ-BUNEVIČIENĖ (Vilniaus universiteto ligoninės Santarikiųklinikos, biomedicinos mokslai, visuomenės sveikata 10B). Oponentai: doc. dr. Saulius VASAREVIČIUS (Vilniaus Gedimino technikos universitetas, technologijos mokslai, aplinkos ininerija ir kratotvarka 04T), doc. habil. dr. Konstancija JANKAUSKIENĖ (Kauno medicinos universitetas, biomedicinos mokslai, visuomenės sveikata 10B). Disertacija bus ginama vieame Aplinkos ininerijos ir kratotvarkos mokslo krypties tarybos posėdyje 2005 m. gruodio 19 d. 14 val. Vilniaus Gedimino technikos universiteto senato posėdiųsalėje. Adresas: Saulėtekio al. 11, LT-10223 Vilnius-40, Lietuva. Tel.: +370 5 274 49 52; +370 5 274 49 56; faksas +370 5 270 01 12; el. patas doktor@adm.vtu.lt Disertacijos santrauka isiuntinėta 2005 m. lapkričio 18 d. Disertaciją galima periūrėti Vilniaus Gedimino technikos universiteto bibliotekoje (Saulėtekio al. 14, Vilnius, Lietuva). VGTU leidyklos Technika 1200 mokslo literatūros knyga. © Ana Usovaitė, 2005
General characteristic of the dissertation Problem of the thesis The Earth surface is constantly exposed to ambient radionuclide radiation. The latter is accompanied by elementary particle radiation of cosmic origin. Amount and character of these cosmic particles keep changing in time due to such factors as heliomagnetic, geomagnetic, state of the Earth atmosphere, etc. As we know, the isotropic flux of cosmic particles continuously moves towards the Earth. Most of these particles come from the galaxy. Due to inevitable interaction with atmosphere gas atoms, the primary cosmic particles are not able to penetrate through the Earth atmosphere. That is why only the secondary particles are detected near the Earth surface, and most of them consist of muons and gamma quanta. It is obvious that cosmic ray flux (CRF) variations near the Earth surface depend on the parameters of the primary cosmic particle flux and their changes produced when on their way particles cross the geomagnetic field power lines. Thus, CRF variations close to the Earth surface may indirectly define the instabilities of the primary cosmic rays and geomagnetic field. Moreover, low-energy radioactive particle radiation, which is always in the air, prevails in first the atmosphere layer above the Earth surface. It is predetermined by radon atoms emanating from the soil and the resulting products of their fragmentation. Besides, the atmosphere is continuously polluted by radiation of technogenic origin. This rather aggravates the CRF researches and the employment of research findings. CRF consists of high-energy particles, known as a hard component of cosmic rays that is almost insensitive to weak external factors close to the earth surface. Thus, the hard cosmic ray flux (HCRF) variations could be used for the prognostic indication of geomagnetic field fluctuations. Geophysical and meteorological factors and changes in the Sun activity have negative impact on human organism, especially on that of sick people. The Sun activity that undergoes habitual changes affects a human being through multiple physical processes, including changes in the geomagnetic field. A result of this impact usually is felt several days later, as a human organism reaction tends to be inert. Observations of the magnetic field are inevitably aggravated by human-created electromagnetic fields that are formed by reason of industry, electrified transport, radio connection and many other reasons. Moreover, these observations require complicated and costly apparatus. Variations of hard cosmic ray flux might, therefore, be used as an indirect indicator of human health impairment, i.e. to the possible extent it should used in prognosis of premonitory prognosis of a possible human health state pathology.
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Topicality of the problem The thesis proposes an indirect indicator of the geomagnetic field variations, i.e. the hard cosmic ray flux. Analysing HCRF variations, a prognostic scheme of a leap of cardiovascular diseases was drafted. The application of this method, most probably, will inform people about the geomagnetic impact and will supplement other existing methods employed to reduce a leap of cardiovascular diseases. Aim of the work 1. Improvement of the construction of gamma spectrometric apparatus sensor by adapting it for the investigation of hard cosmic rays. 2. Investigation of the character of hard cosmic rays near the Earth surface and finding out of its peculiarities and variation regularities. 3. dynamics of cardiovascular diseases in Vilnius.Analysis of 4. Application of HCRF research findings for prognosis of cardiovascular diseases, establishment of prognosis criteria and definition of its efficiency. Tasks to be solved: 1. Assessment of cosmic ray researches and the analysis of the impact of geomagnetic, meteorological factors and the Sun activity changes on a human organism in the world and in Lithuania. 2. Improvement of the construction of gamma spectrometric apparatus sensor aiming at higher precision and reliability of measurement of the hard cosmic ray flux. 3. Observations of HCRF for the period 2001 to 2005 and processing of HCRF measurement findings in the integrated energy diapasons and the diapasons indicated in the work. Processing of the findings of observations carried out in 19971999. 4. of the hard cosmic ray flux and its changes.Investigation 5. on the number of cardiovascular diseases in VilniusCollection of the data and their statistical analysis. 6. Proposal of empiric criteria of HCRF changes that help to forecast a leap of cardiovascular diseases and apply statistical methods of mathematical simulation in order to find out the efficiency of the prognosis. 7. Finding out of the connection between the course of cardiovascular diseases and HCRF variations in the integrated diapason. Scientific novelty 1. A long-term monitoring of the hard cosmic ray flux was carried out, and the findings were processed investigating HCRF variations in energy diapasons. 2. The motion of HCRF change in time-span near the Earth surface.For the first time, the research was carried out trying to find out the connection between
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the changes of the secondary cosmic ray flux and a leap of cardiovascular diseases. 3. To forecast the leaps of cardiovascular diseases,for the first timean indirect indicator HCRF was applied, the variations of which define the changes in the geomagnetic field and their impact on a human being. 4. A connection between the hard cosmic ray flux variations in the integrated diapason and leaps of cardiovascular diseases was found out; besides, the reliability of this connection was estimated. Practical value 1. Gamma spectrometric apparatus used for measurement of the hard cosmic ray flux was improved. 2. In this work, geomagnetic field variations were assessed with the help of an indirect indicator, i.e. the hard cosmic ray flux variantions. The results of their observations give a supplementary warning about the impact of geomagnetic field variations on a human organism. 3. The carried out researches make it possible to forecast leaps of cardiovascular diseases taking account of the hard comsic ray flux variations. 4. It will be possible, most probably, to base on the results of this prognosis in the clinical practice. Work approval Eight scientific publications on the subject of the dissertation were published: one of them was published in a publication included into the list of the ISI; one in proceedings included into the list of the ISI, two in foreign journals, two in journals included into the LL list, two in proceedings of national scientific conferences. The results of the scientific researches were presented and discussed at four international conferences and five national conferences. The scope of the scientific work The thesis consists of an introduction, four chapters, general conclusions, references, publications and readers, reports on the subject of the thesis. In total, the thesis contains 126 pages of the text, 59 figures and 25 tables. 1. Variations of the hard cosmic ray flux and geomagnetic field and their impact on the environment In the upper atmosphere layers of the Earth, the primary cosmic rays expend their energy on rigid collision with nitrogen and oxygen atomic nuclei. As a result of these collisions, the secondary cosmic rays are formed that are able to reach the Earth surface. Investigation of the lengths of a free transit of the primary cosmic protons and heavier particles revealed that the total thickness of the atmosphere consists of 15 average free transit lengths of a
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proton nucleus and 41 average free transit length of a helium nucleus. Thus, the probability that the primary particles reach the Earth surface without any collisions is very low. Bellow 20 km, all cosmic rays are secondary. Every primary high-energy particle generates a cascade of secondary particles. Many secondary particles appear instead of a primary particle. They are divided into hadronic, muonic and electronic-photonic components. At the sea level, muon flux accounts for about 70% of the total amount of particles. The recent decades have seen extensive global researches on the impact of the Sun activity and geomagnetic field on a human organism. The impact of the Sun activity and the geomagnetic factors on cardiovascular diseases has been researched by many scientists. E. Stoupel has detected the connection between the primary cosmic ray intensity, the Sun activity, the geomagnetic field activity and the state of a human organism. Observation of the primary cosmic protons is a complex and costly matter. The number of observation stations that carry out this type of observation is below twenty all over the world. The variations of the primary cosmic particle amount may not reflect the changes of the geomagnetic field in a specific point, which rather aggravates the prognosis of the impact on a human organism. That is why HCRF observations near the Earth surface is a more appropriate method for the prognosis of certain diseases, including cardiovascular diseases. 2. Methodology for measurement of the hard cosmic ray flux The cosmic ionising radiation consists of the soft cosmic radiation component and the hard cosmic radiation component. The aim of the experimental tests is to investigate the hard cosmic component and to analyse its energy spectrum. The hard component consists of high-energy gamma quanta and muons. In this work all experimental tests are carried out in the gamma radiometry way.γ-spectrometric apparatus with a scintillation sensor NaI(Tl) was used for the tests of the hard cosmic ray flux. It is an apparatus that converts the absorbed gamma quantum intothe electric current impulse. intensity Its depends on gamma quantum energy. A gamma spectrometer, used for measurement of the hard cosmic ray flux intensity, operates on a principle of scintillation-photoelectric dosimetric meter. The main elements of a gamma spectrometer are a sensor and a photoelectric multiplier, assembled in a special steel frame covered with several layers of lead the so-called house. The sensitive elements of the measurement apparatus consists of a 6.3 cm wide and high NaI(Tl) crystal scintillation sensor and a photoelectric multiplier.
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A block scheme of measuring apparatus is given in Figure 2.1. Cosmic particles that penetrate through the protective layer of lead get into a scintillation NaI(Tl) crystal (1). In the crystal, they generate short light microflashes, the intensity of which depends on the particle energy. Further, the signal gets into the photoelectric multiplier (2), in which the light impulse is converted into the electric signal. A photoelectronic multiplier (2) forms electric impulses, the intensity of which also depends on the energy of falling particles [1, 3, 6]. NaI(Tl) crystal (1) and photoelectric multiplier (2) makes a solid apparatus a scintillation block. The photoelectric multiplier is supplied with 1,2 kV power from high tension power ack (Figure 2.1). 3 4 5 6 Figure 2.1. A block 1 NaI(Tl) scintillation sensor; scheme of HCRF meter: 2 photoelectric multiplier; 3 high tension power source; 4 linear amplifier; 5 discriminator; 6 computer; 7 protective layers of lead Further, the signal gets into the linear amplifier (4), from which, after being amplified to the necessary level, it gets into the impulse analyser (5). In the analyser, impulses that bear information about the amount of all measured particles of certain energy are emitted in the set period of time. The impulse converter-amplifier (4) and the impulse analyser (5) are assembled in a single integrated board in the computer (6). The scintillation block, NaI(Tl) crystal (1) and the photoelectric converter (2) are covered with multi-layer lead protection (7), i.e. put into the lead house. Its construction is given in Figure 2.2. The total thickness of multi-layer lead screens (6) inside and outside the house can be changed by inserting or removing extra lead plates. Moreover, individual lead layers are separated by steel sheets and air gaps (Figure 2.2). Thorium232these plates (5). Natural ionising radiationTh reference was put on was measured without a radioactive reference. The apparatus records the
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6 4
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amount of gamma quanta and muons after Compton scattering in the lead layer and apparatus sensor [1, 3, 6]. 5 7 3 Figure 2.2. The house construction: 1 scintillation NaI(Tl) crystal; 2 photoelectric multiplier; 3 lead screens; 4 holding constructions; 5 radioactive reference; 6 changeable lead protection layers; 7 air gaps In order to separate HCRF from other components of the general radioactive background, a minimal thickness of the lead screen, which prevented low-energy gamma quanta from entering, was chosen. A minimal 9 cm thick lead screen, which would prevent low-energy quanta from entering, was defined theoretically and proved experimentally. Increasing the thickness of the lead screen from 9 to 12 cm, the amount of penetrating particles did not change substantially. Thus, there is no need to increase the thickness of the screen above 9 cm [6]. HCRF measurement was carried out every 15 minutes. The work analyses the data of HCRF observations of 20012004 in four energy diapasons. In total, the primary data included more than 700 000 numbers. This is a lot, and these data were prepared for further processing and use. This could be possible only after creating a huge database adapted for the researches carried out in this work. The main peculiarity of the data processing system being created is that huge amounts of data are involved, although mathematical calculations are not complicated. To that end,an original database created; it facilitates working with was the data of 20012004.
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