1,721,029 research outputs found
Characterisation of the magnetized interstellar medium
No full textU ovom radu prikazana je analiza struktura u simuliranim polarimetrijskim opažanjima korištenjem metoda RM sinteze i Rolling Hough transformata. Simulirana su opažanja polariziranog intenziteta na rasponu frekvencija u radio području nekoliko magnetohidrodinamičkih modela kompresibilne turbulentne međuzvjezdane tvari i modela sudara super-ljuski. Pokazano je da je usmjerenost depolariziranih struktura u opažanjima turbulentne meduzvjezdane tvari prisutna samo ako model sadrži homogenu komponentu magnetskog polja, no da su dovoljne vrijednosti jakosti homogene komponente manje od onih opaženih u spiralnim krakovima Mliječnog puta. Nadalje, pokazano je da udio depolariziranih piksela pada povećanjem kinematičke viskoznosti i otpornosti te jakosti homogene komponente magnetskog polja. Naposljetku, pokazano je da su sudari super-ljuski opazivi polarimetrijskim mjerenjima te da izgled struktura ovisi o gustoći elektrona kozmičkih zraka koje uzrokuju emisiju unutar spomenutog modela.In this thesis we present an analysis of structure visible in synthetic polarimetric observations using Rotation measure synthesis and the Rolling Hough transform. We generated synthetic observations of polarized intensity over a range of radio frequencies for multiple magnetohydrodynamic models of compressible turbulent interstellar matter and a single model of a super-shell collision. It was found that depolarized structures in observations of the turbulent ISM show significant alignment only in models with a homogeneous magnetic field component, but that the sufficient strength was lesser than the values observed in the spiral arms of our Galaxy. Furthermore, it was shown that the percentage of depolarized pixels decreases with increasing kinematic viscosity, resistivity and strength of the homogeneous magnetic field component. Lastly, we have shown that super-shell collisions are detectable by radio polarimetric observations and that the visible structure largely depends on the synchrotron emitting local cosmic ray electron density
Nucleosynthesis in physics class
Get PDFOvaj diplomski rad će pokušati odgovoriti na bitna pitanja poput: Kako su elementi nastali? Zašto su neki elementi više puta zastupljeniji od drugih? Pri tome će se opisivati mehanizmi stvaranja elemenata, kako tijekom početka evolucije Svemira, tako i tijekom kasnijih perioda pa sve do danas. U radu će biti predstavljeni neki od najbitnijih procesa i reakcija odgovornih za današnji sastav tvari i elemenata. Opisivat će se više različitih mehanizama odgovornih za sintezu nekih od elemenata. Pokušat će se objasniti procesi u zvijezdama na način da to razumiju ne samo znanstvenici i fizičari, nego i srednjoškolci. Diplomski rad će pokušati sažeto objasniti nastanak svakog od bitnih elemenata, kako onih lakših, tako i onih težih. Konačno, analizirat će se gradivo nuklearne fizike u srednjoj školi preko udžbenika i usporeĎivati sa obrazovnim ishodima iz kurikuluma za fiziku u srednjoj školi. Na kraju će se pokušati dati okviran način uklapanja teme nukleosinteze u školski program.This thesis will try to answer important questions such as: How did elements come into existence? Why are some elements more abundant than others? In addition to that, we'll describe the mechanism of element creation, during the beginning stages of Universe's evolution, as well as during later periods up until today. In the work we'll also present some of the most important processes and reactions responsible for the current composition of substances and elements. Descriptions will include various mechanisms responsible for the synthesis of some of the elements. We'll try to explain the processes in the stars in a way that is understandable not only to scientists and physicists, but also to highschoolers. Furthermore, this thesis is an attempt to succintly explain the creation of every important element, lighter as well as heavier ones. Finally, the analysis will cover the material on nuclear physics that is studied in high school through textbooks and compare with the educational results from the curiculum for physics in high school. In the end, the attempt will be made to provide a broader way to include the subjects of nucleosynthesis in the school/educational progra
The 10B + 10B nuclear reactions and structure of light atomic nuclei
Get PDFLake atomske jezgre u okolici A = 10 pokazuju vrlo različite strukture na bliskim energijama pobuđenja, od ljuskastih do sasvim egzotičnih, kao što su molekulska stanja s više valentnih nukleona, ili Bose-Einsteinovi kondenzati. Eksperimentalni podaci u tom području nepotpuni su i često kontroverzni. S ciljem proučavanja jezgri iz tog masenog područja, nuklearne reakcije 10B + 10B mjerene su na dvije energije snopa = 50 i 72.2 MeV. Produkti reakcija bilježeni su detektorskim sustavom sastavljenim od četiri silicijska ΔE-E teleskopa, koji je pokrivao veliki prostorni kut i omogućavao mjerenje jednostrukih događaja, te dvo- i tročestičnih koincidencija. Proučavana je selektivnost pobuđivanja pojedinih stanja, te njihov sekvencijalni raspad. U skladu sa složenom strukturom jezgre 10B, čija su niskoležeća stanja mješavina ljuskastih (jednočestičnih) i klasterskih konfiguracija tipa 6Ligs + α ili 6Li(0+2 , 1) + α, te visoki spin osnovnog stanja jezgre 10B (Jπ = 3+), pobuđen je čitav niz stanja na visokim energijama pobuđenja, vjerojatno visokog spina, od kojih se mnoga uklapaju u modele koji predviđaju neobične klasterske strukture tih jezgara, a neka tek ugrađuju u novije teorijske modele. Mehanizmom prijenosa neutrona, odnosno protona, vrlo je jako pobuđeno nekoliko stanja u jezgrama 11B i 11C, na visokim energijama pobuđenja, za koja dosad nije zabilježeno pobuđivanje prijenosom jednog nukleona. U spektrima pobuđenja 9Be i 9B nedostaje prvo pobuđeno stanje izrazito klasterske građe, no s druge strane javljaju se stanja koja se vrlo lijepo uklapaju u rotacijske vrpce osnovnih stanja tih jezgra, kao članovi 9/2−. Prijenosom dva nukleona intenzivno je pobuđen kanal 8Be + 12C. Detekcija tri α- čestice nastale kroz ovaj kanal omogućila je rekonstrukciju detalja procesa 10B + 10B → 5α, koji se odvija preko Hoyleovog stanja u jezgri 12C, ali i rijetko isticanog stanja na Ex = 24.4 MeV, kojemu još nisu poznati spin i paritet. U tročestičnom izlaznom kanalu 10B + d + 8Be, pobuđeno je i rijetko viđeno stanje na visokoj energiji pobuđenja u 12C (na 30.33 MeV), koje se raspada kroz egzotični kanal 10B + d. Dobiveni spektri pokazuju veliku selektivnost pri prijenosu tri nukleona u stanja jezgre 13C, a jaki su i prijenosi α-čestice u pojedina stanja jezgre 14N, te 6Li u stanja jezgre 16O. Naročito je jako izraženo α-stanje na 18.9 MeV u 13C, te stanja 14N na 13.2 i 15.39 MeV, koja se uklapaju u vrlo nedavne AMD račune za jezgru 14N, kao glava i pobuđeno 5+ stanje rotacijske vrpce Kπ = 3+ bazirane na 10B(3+) + α strukturi. Još jedan rezultat ovog rada svakako je doprinos na području kalibracije DSSSD detektora, gdje je razvijena nova metoda i posebni programski paket prilagođen za njeno jednostavno korištenje.A rich variety of nuclear structures occur in light nuclei, in the vicinity of the A = 10 region, at similar excitation energies: from shell-model states to very exotic ones, e.g. molecular states with multiple valence nucleons or Bose-Einstein condensate states. Experimental data for this region is incomplete and often controversial. In order to study the structure of nuclei in this mass region, 10B + 10B reactions were measured at beam energies of 50 and 72.2 MeV. Reaction products were detected using a detector setup that consisted of four ΔE-E silicon detector telescopes, covering a large solid angle and allowing for the detection of single events as well as two- and three-particle coincidences. The selectivity of this reaction for populating different excited states was studied, together with a sequential decay of states in question. The complex structure of the low-lying states of the 10B nucleus, which can be described as a mixture of shell model and cluster configurations of the type 6Ligs + α or 6Li(0+2 , 1) + α, together with a high spin of the ground state Jπ = 3+, enables this reaction to populate a range of different high-spin states at high excitation energies. The theories predicting an existence of exotic structures of the A = 10 nuclei can model many of these states, while some of the states are yet to be studied using new theoretical models. One nucleon transfer reactions populated a few well defined high excitation energy states of the 11B and the 11C. Some of these states were populated in a one nucleon transfer reaction for the first time. In the excitation energy spectra for the 9B and the 9Be the first excited states, characterized as highly clustered structures, are missing. On the other hand, states that nicely fit into rotational bands of first excited states of these nuclei are clearly observed as their 9/2− members. Two nucleon transfer reactions strongly populated the 8Be + 12C channel. A coincident detection of three α-particles provided the information necessary to reconstruct the details of the 10B + 10B→5α reaction. That exotic reaction proceeds not only through the Hoyle state of the 12C, but also through a rarely mentioned 12C state at Ex = 24.4 MeV, whose parity and spin of are still unknown. In the three particle channel 10B + d + 8Be a seldom observed high energy state in 12C (Ex = 30.33 MeV) that decays through an exotic channel 10B + d was populated. Excitation energy spectra of 13C show a high selectivity in the three nucleon transfer channel. An α-transfer into states of the 14N is very strong, as well as 6Li transfer reaction to the states of the 16O. A very strong α-decaying state is seen at the Ex = 18.9 MeV in the 13C. Excited states of the 14N at 13.2 and 15.39 MeV of excitation energy fit nicely to a recent AMD calculations as the head and the 5+ state of the 10B(3+) + α rotational band (Kπ = 3+). For the needs of this theses a novel calibration method was developed. It was implemented in a set of tools that allow an easy and accurate calibration of DSSSD detectors
Nuclear reactions 10B+12C and the structure of light atomic nuclei
Get PDFU ovom se radu proučavaju nuklearne reakcije ulaznog kanala 10B+12C s ciljem istraživanja građe lakih atomskih jezgara oko nukleonskog broja A=10. Za jezgre iz tog masenog područja, poznata su mnoga stanja na bliskim energijama, koja se ne mogu opisati unutar istog modela. U ovom se radu stoga opisuju razni modeli, od običnog modela ljusaka do egzotičnih modela nuklearnih molekula i Bose-Einsteinovih kondenzata. S ciljem pronalaženja novih takvih stanja, izabrana je jezgra 10B kao projektil, s obzirom da su već njena niskoležeća stanja kombinacija modela ljusaka i klasterskih konfiguracija, a spin osnovnog stanja, iznimno je visok i iznosi Jπ =3+. Mjerenja su provedena na energiji snopa od 50 MeV-a, dok su produkti reakcije bilježeni sustavom od četiri ΔE-E silicijska detektora velikog prostornog kuta, koji omogućavaju mjerenja jednostrukih događaja, ali i dvo- i tročestičnih koincidencija. Analiza jednostrukih događaja, omogućila je rekonstrukciju spektara jezgri 12C, 13N, 15N, 15O i 16O, dok su iz dvočestičnih koincidencija rekonstruirani spektri 8Be i 14N. Na temelju tih spektara i recentnih eksperimentalnih i teorijskih radova, diskutirana je selektivnost pobuđivanja pojedinih stanja i struktura samih jezgara na koju ona ukazuju.In this work we study the nuclear reactions 10B+12C, with the goal of exploring the structure of light atomic nuclei around the nucleon number A=10. It is well known that those nuclei have many energy levels which are very close yet their structure and properties cannot be modeled in the same framework. For this reason we describe several different models, ranging from a simple Shell Model to several exotic ones, including the Nuclear Molecule model and the Bose-Einstein Condensate model. With the goal of finding states which correspond to these models, we have chosen the nucleus 10B as the projectile, because its low-lying states already have a mixture of shell model and cluster configurations and the spin of its ground state is extremely high, namely Jπ =3+. The projectile energy used was 50 MeV, while the detector system was made from four ΔE-E silicon detectors, covering a very wide solid angle. Both single-particle and multi-particle detection was possible. From the single particle detection, we have reconstructed the spectra of the following nuclei 12C, 13N, 15N, 15O and 16O, while the two particle detection was used to reconstruct the spectra of 8Be and 14N. A discussion on the selective activation of energy states and the corresponding structure of the nuclei is performed, based on the reconstructed spectra and the recent theoretical and experimental work in the field
Classification of variable stars using machine learning methods
No full textProučavanje promjenjivih događaja u svemiru koji se događaju na relativno kratkim vremenskim skalama od velikog je interesa za astrofizičare jer se iz njih mogu dobiti mnoge korisne informacije. Isto vrijedi i za promjenjive zvijezde, to jest zvijezde čiji sjaj nije konstantan. Promatranjem takvih zvijezda moguće je odrediti svojstva zvijezda, u nekim slučajevima i jednostavnije nego kod promatranja nepromjenjivih zvijezda, kao i udaljenosti u svemiru. Kako bismo bili sigurni da su dobivene informacije ispravne, važno je pravilno odrediti kojoj vrsti pripada promjenjiva zvijezda. Međutim, ručno određivanje kategorije za svaku od stotina tisuća promjenjivih zvijezda koje se opažaju u pregledima neba veoma je dug i težak proces. Kako bi se isti ubrzao i automatizirao, mogu se koristiti metode strojnog učenja. U ovom radu korištene su metode klasifikacije i grupiranja sadržane u Scikit-Learn paketu u programskom jeziku Python kako bi se kategoriziralo oko 100000 promjenjivih zvijezda opaženih u Catalina pregledu neba. Za klasifikaciju korišten je Support Vector Machine (SVM) algoritam nadziranog strojnog učenja, a za grupiranje Gaussian Mixture Model (GMM) algoritam nenadziranog strojnog učenja. Dobiveni rezultati uspoređeni su s kategorizacijom provedenom u Catalina pregledu neba kako bi se dobio uvid u to koja metoda je preciznija. Rezultati pokazuju da je SVM algoritam bolji izbor za klasifikaciju ovakvog tipa podataka, ali i on pokazuje neka odstupanja od Catalina pregleda neba. Zaključeno je da se metode strojnog učenja mogu koristiti u traženu svrhu, ali potrebno je još proučavanja kako bi se proces optimizirao.Studying variable cosmic events which happen on relatively short time scales is of great interest for astrophysicists because of a plenitude of useful information one can receive from them. The same is true for variable stars, which are stars whose light is not constant. By observing such stars, it is possible to determine properties of stars, in same cases with less difficulty than by observing non-variable stars, and cosmic distances. To assure that the received information is correct, it is of great importance to correctly determine the type of each variable star. However, determining categories of hundreds of thousands of variable stars in sky surveys is a very long and difficult process. In order to accelerate and automatise said process one can use the machine learning methods. In this paper, the methods of classification and clustering contained in the Scikit-Learn package of the Python programming language were used to categorise roughly 100000 variable stars observed in the Catalina Sky Survey. The supervised learning Support Vector Machine (SVM) algorithm was used for classification and the unsupervised learning Gaussian Mixture Model (GMM) algorithm was used for clustering. Obtained results were compared with the categorisation from the Catalina Sky Survey to gain an insight in the precision of each method. The results show that the SVM algorithm is a better choice for classification of this type of data, but it also shows some deviations from the Catalina Sky Survey. It was concluded that the machine learning methods can be used for desired purposes, but further study is needed to optimise the process
Neutron-rich potassium nuclei
Get PDFOsnovna tema ovoga rada je proučavanje neutronski bogatih jezgara kalija masenih brojeva 41–46. U okviru rada proučeni su podatci vezani uz elektromagnetske prijelaze pobudene nuklearnom reakcijom 40Ar+ 208Pb mjerenom magnetskim spektrometrom PRISMA u koincidenciji s detektorom γ-zračenja CLARA. Korištenjem neutronski bogatog stabilnog snopa 40Ar možemo u izlaznom kanalu imati pobuđene izotope koji su nastali pobiranjem ili ogoljavanjem nukleona. Kanali pobiranja protona od velikog su interesa jer su do sada na mjerenjima oko kulonske barijere samo nekoliko puta identificirani u atomskom i masenom broju. Upravo su izotopi kalija dobiveni reakcijama pobiranja i protona i neutrona. U ovom smo radu identificirali njihove karakteristične elektromagnetske prijelaze kroz cijeli lanac izotopa kalija. Ove rezultate smo usporedili s prethodno publiciranim rezultatima, kao i s teorijskim računom modela ljusaka. Uočeni su do sad nepoznati elektromagnetski prijelazi te se smještanjem stanja u sheme energijskih nivoa i usporedbom s teorijskim računima došlo do novih informacija o nivoima, koji su već uočeni, ali kojima nije dodijeljen spin i paritet. Uočili smo i da se udarni presjek u svim pobuđenim jezgrama kalija raspoređuje podjednako na stanja negativnog i na stanja pozitivnog pariteta. Uočili smo i snažno pobuđenje stanja najvišeg spina za danu energiju (“yrast”). Raspravljali smo o inverziji prvog pobuđenog i osnovnog stanja, 1/2+ i 3/2+ kod neparno-parnih i 3− i 2− kod neparno-neparnih jezgri, gdje do zamjene nivoa dolazi zbog jakog miješanja protonskih konfiguracija, kako se popunjava neutronska ljuska f7/2.The main topic of this thesis are neutron-rich potassium nuclei with mass numbers ranging from 41 to 46. As a part of this work we analysed and interpreted data related to the electromagnetic transitions excited by the nuclear reaction 40Ar + 208Pb measured with the PRISMA magnetic spectrometer coupled with the CLARA γ -ray detector. Using a neutron-rich stable beam of 40Ar we can observe excited isotopes in the exit channel, originating from nucleon pick-up or stripping. Proton pick-up channels are a major research interest as up to now they have rarely been identified in terms of their atomic and mass numbers in measurements near the Coulomb barrier. In our measurement isotopes of potassium are created by pick-up reactions of neutrons and protons. Our main objective was to identify their characteristic electromagnetic transitions throughout the complete potassium isotopic chain. These results were compared to previously published results and theoretical predictions of the nuclear shell model. We observed so far unknown electromagnetic transitions and, by embedding corresponding levels in the energy level scheme and comparing them with shell model calculations, obtained new information on previously known levels of unknown spin and parity. Furthermore, we observed that the cross section in all excited potassium nuclei is equally distributed among states of positive and negative parity. We also observed strong excitations of highest spin states for a given energy (“yrast”). Finally, we discussed the inversion of the first excited state and ground state, 1/2+ and 3/2+ for odd-even nuclei and 3− and 2− for odd-odd nuclei, in which the inversion is caused by strong mixing of proton configurations, as the neutron shell f7/2 is being filled
Modeling Radiation from the Solar Atmosphere in the sub-mm, mm and cm Wavelength Range
Get PDFNa slikama Sunca u milimetarskom području mogu se uočiti područja povećane emisije (visokotemperaturna područja, VTP) i područja povećane apsorpcije (niskotemperaturna područja, NTP). Termičko zakočno zračenje i žiromagnetsko (ciklotronsko) zračenje su procesi koji mogu objasniti temperature sjaja dobivene mjerenjima. Koristimo postupak za računanje temperature sjaja za danu valnu duljinu i model atmosfere koji integrira jednadžbu prijenosa zračenja za termičko zakočno zračenje. Do sada je ovaj postupak primijenjen samo na zračenje valne duljine od 8 mm. Cilj ovog rada je primijeniti modele za različite strukture Sunčeve atmosfere na širi spektar valnih duljina (od 0.3 mm do 1 cm), otprilike jednak onome na kojem radi Atacama Large Millimeter/submillimeter Array (ALMA) te dobivene rezultate usporediti s dostupnim mjerenjima. Zaključujemo kako je termičko zakočno zračenje dominantni mehanizam zračenja na submilimetarskim i milimetarskim valnim duljinama koji može objasniti dosadašnja mjerenja intenziteta zračenja Sunca. U bliskoj budućnosti, rezultati modela će se moći usporediti s novim mjerenjima pomoću teleskopa ALMA.Maps of the Sun in millimeter wavelength range reveal emission features (high temperature regions, HTR) and apsorptive features (low temperature regions, LTR). Thermal bremsstrahlung and gyromagnetic (cyclotron) radiation mechanism can be important for explaining the observed phenomena. We use a procedure for calculating the brightness temperature for a given wavelength and model atmosphere, which integrates the radiative transfer equation for thermal bremsstrahlung. Until now, it has been used just for the radiation with wavelength of 8 mm. The aim of the present work is to apply the models for different structures of the solar atmosphere on a broader wavelength range (from 0.3 mm to 1 cm), closely related to that of Atacama Large Millimeter/submillimeter Array (ALMA), and to compare the results with observations. We conclude that thermal bremsstrahlung is the only important radiation mechanism in the submillimeter and millimeter wavelength range, which can explain previous observations of the Sun’s intensity of radiation. In the near future, we will be able to compare the results of our models to new observations of ALMA telescope
Development of in situ setup for optical characterization of implanted NV colour centres in diamond
No full textZahvaljujući jedinstvenim optičkim i spinskim svojstvima, centar boje dušik-vakancija (NV) u dijamantu zauzima vrlo važno mjesto u grupi razmatranih sustava koji se predlažu kao osnova za nadolazeće kvantne tehnologije. Radi svoje robusnosti te mogućnosti pouzdane inicijalizacije, manipulacije i očitanja kvantnih stanja na sobnim temperaturama, primjenu je pronašao u području kvantne obrade podataka i komunikacija kao osnova za razvoj kvantnih bitova, u području nanotehnologija kao lokalni kvantni senzor za razne fizikalne parametre, u biotehnološkom području kao fluorescentni biomarker velike fotostabilnosti te u raznim drugim područjima. Učinkovite tehnike formacije i detekcije centara boje važan su aspekt realizacije svih nadolazećih novih tehnologija baziranih na njima. Sa svrhom objedinjena koraka formacije i detekcije centara boje, u ovom je radu prikazan razvoj novog in situ postava za optičku karakterizaciju NV centara boje u dijamantu. Mjerenjem ionoluminiscencije (IL) i fotoluminescencije (PL) na monokristalnom dijamantu tipa IIa uporabom postava za detekciju luminescencije inducirane ionskim snopom (IBIL) inkorporiranog u komoru mikroprobe i konfokalnog mikroskopa te usporedbom s IL, PL i iono-fotoluminescentnim (IPL) mjerenjima na monokristalnom dijamantu tipa IIa, polikristalnom dijamantu tipa Ia i monokristalnom dijamantu tipa Ib mjerenih uporabom novorazvijenog postava za detekciju luminescencije inducirane laserom i ionskim snopom (LIBIL), ispitane su ovisnost intenziteta emisijskih linija promatranih centara o deponiranoj dozi te mogućnosti i ograničenja razvijenog postava.Due to its unique optical and spin properties, the nitrogen-vacancy (NV) colour center in diamond is a very important physical system expected to serve as basis for the new generation of emerging quantum technologies. Owing to its robustness and the fact that its quantum state can be initialized, manipulated and measured with high fidelity at room temperature, it has found application in quantum information processing and communications as basis for the development of qubits, in nanotechnology as a local quantum sensor for a number of physical parameters, in biotechnology as a fluorescent biomarker of high photostability and many other fields. Efficient techniques for colour center formation and detection are a crucial aspect for development of all upcoming new technologies based on them. With the purpose of unifying the steps of formation and detection of colour centers, this thesis presents the development of a new in situ setup for optical characterization of NV colour centers in diamonds. Ionoluminescence (IL) and photoluminescence (PL) measurements on a type IIa single crystal diamond, measured on the ion beam induced luminescence (IBIL) detection setup incorporated into the microprobe chamber and the confocal microscope, were used as a benchmark for IL, PL an iono-photoluminescence (IPL) measurements on a type IIa single crystal diamond, type Ia polycrystalline diamond and type Ib single crystal diamond measured on a newly developed laser and ion beam induced luminescence (LIBIL) detection setup. By comparing the measurements from different techniques, the dependence of emission line intensity vs fluence and radiation hardness for observed colour centers were tested along with the advantages and limitations of the newly developed setup
Neutron-rich heavy nuclei
No full textU okviru rada identificirani su karakteristični elektromagnetski prijelazi jezgara olova 205-210^Pb proizvedeni nuklearnom reakcijom 40^Ar+208^Pb mjerenom magnetskim spektrometrom PRISMA u koincidenciji s detektorom gama-zračenja CLARA na akceleratorskom postrojenju INFN - LNL, Italija. U spektrima pobuđenja izotopa olova izazvanih reakcijom prijenosa neutrona opažena su snažna pobuđenja jednočestičnih stanja kao i kolektivnih stanja od kojih je najznačajnije 3^- stanje izotopa 208Pb. Stanje 3^- igra važnu ulogu u spektrima pobuđenja susjednih jezgara. Opažena su i pobuđenja koja se mogu opisati vezanjem kolektivnih i jednočestičnih stanja. Jakosti elektromagnetskih prijelaza korištene su za izvrednjavanje udarnih presjeka pobuđenih stanja te evaluaciju udarnog presjeka osnovnog stanja usporedbom podataka mjerenja fragmenata i fragmenata u koincidenciji s γ- zračenjem. Dobiveni rezultati uspoređeni su s kodom GRAZING. Takav postupak nam je pomogao u evaluaciji udarnog presjeka u drugim mjerenjima, posebno onih koji koriste (manje intenzivne) radioaktivne snopove. Pokazalo se da su reakcije prijenosa nukleona pogodne za proizvodnju neutronski bogatih teških jezgara kada se koriste neutronski bogati snopovi kao laki partneri u reakciji.Within the work, characteristic electromagnetic transitions of 205-210Pb isotopes, produced in the 40^Ar + 208^Pb nuclear reaction, were identified. The reaction was measured by a magnetic spectrometer PRISMA coupled to the CLARA gamma-ray detector at the INFN-LNL accelerator complex, Legnaro, Italy. In the neutron transfer channels, strong excitations of single-particle states as well as collective states were observed, the most significant of which was the 3^- state in 208^Pb. The 3^- state plays an important role in the excitation spectra of neighboring nuclei. Excitations of states with the structure that can be described as a coupling of collective and single-particle states have also been observed. The intensities of electromagnetic transitions were used to evaluate cross sections of the ground state by comparing the data where only fragments, with the data where fragments in coincidence with gamma radiation were detected. The obtained results were compared with the code GRAZING. Such a procedure helped us to evaluate cross sections of ground state in other measurements, especially those using (less intensive) radioactive beams. Multinucleon transfer reactions have been shown to be suitable for the production of neutron-rich heavy nuclei when neutron-rich beams are used as light partners in the reaction
7Li induced nuclear reactions on light nuclei
Get PDFU ovom radu proučavane su nuklearne reakcije izazvane snopom litijevih iona 7Li, energije 16 MeV na metama 12C, 7LiF i 6LiF. Izlazne čestice detektirane su dvostranim silicijskim vrpčastim detektorom (Micron Semiconductor tip W1 debljine 1000 μm) čije je središte bilo postavljeno na kutu od 21,8° u odnosu na smjer ulaznog snopa. Iz prikupljenih podataka rekonstruirani su energijski spektri pobuđenja jezgara 6,7Li, 9,10Be, 12C, 19F i 15N te su identificirana pobuđena stanja u rasponu energija 0-10 MeV. Detekcijom izlaznih čestica identificirani su procesi raspršenja iona 7Li na jezgrama meta 7Li, 12C, 19F i 27Al, elastično raspršenje (6Li(7Li, 6Li)7Li) sa detektiranim ionima 7Li i 6Li te procesi prijenosa tritona 7Li(7Li, α)10Be, 6Li(7Li, α)9Be, 12C(7Li, α)15N.The Diploma thesis examines nuclear reactions studied on multiple targets (12C, 7LiF, 6LiF) induced by the 7Li beam at energy of 16 MeV. The emitted particles were detected with double sided silicon strip detector (Micron Semiconductor type W1, 1000 μm of thickness) whose center was positioned at an angle of 21,8°to incident beam. Collected data was used for excitation energy spectra reconstruction of 6,7Li, 9,10Be, 12C, 19F and 15N nuclei. Based on the data, excitation states were identified in energy range of 0-10 MeV. Detected nuclear reactions include elastic and inelastic scattering of 7Li on 7Li, 12C, 19F and 27Al, detection of scattered 6Li from 6Li(7Li, 6Li)7Li reaction and triton cluster transfer reactions 7Li(7Li, α)10Be, 6Li(7Li, α)9Be, 12C(7Li, α)15N
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