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A feasibility study of the (3He,8He) reaction with the K600 magnetic spectrometerSwartz, Jacobus Andreas 03 1900 (has links)
Thesis (MSc (Physics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Highly exotic nuclei can be studied in rare reactions using stable beams, with macroscopic
intensities, and thick targets. Exotic nuclei are interesting for a number of reasons e.g. for
testing nuclear models under conditions of high isospins. In the case of very neutron-deficient
nuclei, two-proton decay is the most recently discovered nuclear decay mode and the subject of
many theoretical investigations involving cluster and shell models.
This thesis presents a feasibility study of investigating light exotic nuclei near the proton drip
line with the K600 magnetic spectrometer. The 27Al(3He,8He)22Al five-neutron pick-up reaction
was investigated at a spectrometer angle of θlab = 8◦ with a beam energy of Elab = 220 MeV.
This reaction can be used to populate highly neutron-deficient nuclei. Should the study of this
reaction prove to be feasible, then a number of nuclei on the proton drip line or beyond could be
investigated. A new data acquisition system, with VME electronics and MIDAS software, was
used along with one new drift chamber, which consists of both an X wire plane and a U wire
plane. The particles 1,2,3H and 3,4He were all identified as outgoing particles from the collision of
3He with 27Al. Cross section calculations were performed for these observed reactions. Discrete
spectra for the (3He,6He) and (3He,8He) reactions could not be identified.
The mass calculation of A ∼ 20 nuclei on the proton drip line depends on the determination
of the Coulomb energy, which differs a lot between mirror nuclei. Mass calculations were performed
for known nuclei in the mass region A ≤ 50, using the Isobaric Multiplet Mass Equation.
Agreement with experimental data was found to be far better in odd nuclei than in even nuclei.
Hence mass predictions were performed for odd nuclei along the proton drip line. / AFRIKAANSE OPSOMMING: Hoogs eksotiese kerne kan bestudeer word in seldsame reaksies deur middel van stabiele bundels,
met makroskopiese intensiteite, en dik teikens. Eksotiese kerne is interessant om verskeie
redes, onder andere om kernfisiese modelle te toets onder omstandighede van ho¨e isospin. In die
geval van baie neutron-arm kerne is twee-proton verval die nuutste ontdekte tipe van kernverval.
Dit is ook die onderwerp van vele teoretiese studies met betrekking tot bondel en skilmodelle.
Hierdie tesis beskryf ‘n uitvoerbaarheidstudie vir die ondersoek van ligte eksotiese kerne naby
die proton drup lyn met behulp van die K600 magnetiese spektrometer. Die 27Al(3He,8He)22Al
vyf-neutron kaapreaksie is ondersoek by ‘n spektrometer hoek van θlab = 8◦ met ‘n bundel energie
van Elab = 220 MeV. Sou die uitvoerbaarheidstudie van hierdie reaksie slaag, dan kan verskeie
kerne op of anderkant die proton drup lyn ondersoek word. ‘n Nuwe data verkrygingssisteem, met
VME elektronika en MIDAS sagteware, is gebruik saam met een nuwe dryfkamer, wat bestaan
uit beide ‘n X draadvlak en ‘n U draadvlak. Die partikels 1,2,3H en 3,4He is almal geidentifiseer
as uitgaande partikels van die botsing van 3He met 27Al. Kansvlak-berekeninge is uitgevoer vir
alle waargenome reaksies. Diskrete spektra kon nie gevind word vir die (3He,6He) of (3He,8He)
reaksies nie.
Die massa berekening van A ∼ 20 kerne op die proton drup lyn is afhanklik van die bepaling
van die Coulomb energie, wat baie verskil tussen spie¨elkerne. Massa berekeninge is uitgevoer vir
bekende kerne in die massa gebied A ≤ 50, deur die gebruik van die Isobariese Multiplet Massa
Vergelyking. Die ooreenstemming met eksperimentele data was baie beter in die geval van onewe
kerne as met ewe kerne. Daarom was die massa voorspellings uitgevoer vir slegs onewe kerne
naby die proton drup lyn.
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Time domain pulse shaping using a genetic algorithmMori, Andrew 03 1900 (has links)
Thesis (MSc (Physics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Through the use of complex Laser Pulse Shaping, numerous fundamental laser induced processes may be controlled as well as studied. This work serves as
an introduction into Laser Pulse Shaping, with the focus on a simple Pulse
Shaping experiment, as well as to determine whether future, more complex
processes may be similarly controlled.
A description of Laser Pulse Shaping theory is presented here, along with a
full explanation of a simple experiment to maximize second harmonic generation
(SHG) through Pulse Shaping. This experiment is simple on a theoretical
level yet complicated in both implementation as well as operation. The experimental
setup and software integration required hardware compatibility in
multiple programming languages. This work was successful in the sense that
a fully automated dispersion compensation system, accomplished through the
use of a genetic algorithm in a feedback controlled loop, was constructed and
tested.
The success of this experiment and the understanding gained in this work
has laid the foundation for further complex Pulse Shaping systems to be achieved
in future. / AFRIKAANSE OPSOMMING: Komplekse Laserpuls-vervorming kan gebruik word om verskeie fundamentele laser-geinduseerde prosesse beide te beheer asook te bestudeer. Hierdie navorsingstuk
dien as n inleiding tot Laserpuls-vervorming, spesifiek gefokus op
n eenvoudige Pulsvervormings-eksperiment. Meer komplekse Pulsvervormingsopstellings
kan toegepas word deur die kennis opgedoen in hierdie tesis.
Die teoretiese agtergrond van Laserpuls-vervormings word bespreek, tesame
met n eenvoudige eksperiment om die Tweede Harmoniek Skeppingsproses
(SHG) te maksimeer deur van Laserpuls-vervorming gebruik te maak. Die
eksperiment is teoreties eenvoudig, waar die implimentering asook bedryf meer
kompleks is. Die bedryf van die eksperiment word in 2 dele hanteer: die
hoofprogram en n Genetiese Algoritme gebruik in optimering. Die werking
van Genetiese Algoritmes asook Ultrakort Pulse (USPs) en pulskarakterisering
word ook bespreek.
Die suksesvolle opstelling van die experiment en ook die eind resultate
wat gevind is, maak dit moontlik om meer ingewikkeld komplekse laserpulsvervorming
experimente te bestudeer.
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Locating the inner edge of a neutron star crustVan Rooy, Milton William 12 1900 (has links)
Thesis (MSc (Physics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The overall goal of this project is to study neutron star properties and locate the transition density
from the core to the crust using fifteen parameter sets of the effective Skyrme nucleon-nucleon
interaction within a method called the dynamical method. Although another approach used to
describe nucleon-nucleon interactions called the modified Gogny interaction is briefly discussed
in this work, along with a second method for locating the transition density called the
thermodynamical method, results using this interaction and method were not generated, but lays
some foundation for a PhD project to be undertaken and potentially showing the relation between
the interactions and results. The importance of results depends on how well other theoretical
approaches to the problem can reproduce those results and to what accuracy. For models to be
valid there also has to be good agreement between the theoretical results and known observables.
In this project some properties of neutron stars, such as the equation of state, saturation density,
binding energy, symmetry energy, slope and incompressibility parameters of symmetry energy
are studied. The transition density is located using the dynamical method. Results of the fifteen
Skyrme parameter sets show excellent agreement with the published values of the properties of
neutron stars and are consistent with their empirical values inferred from nuclear laboratory data,
thus validating the use of the Skyrme interactions for describing nuclear matter. / AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie projek is om neutron ster eienskappe te bestudeer en die
oorgangsdigtheid vanaf die kors na die kern te vind deur gebruik te maak van vyftien parameter
stelle van die effektiewe Skyrme nukleon-nukleon interaksie binne ‘n metode genaamd die
dinamiese metode. Alhoewel ‘n ander benadering vir die beskrywing van nukleon-nukleon
interaksies, genaamd die gewysigde Gogny interaksie kortliks in hierdie werk beskryf word,
asook ‘n tweede metode, genaamd die termodinamiese metode om die oorgangsdigtheid te
bepaal, was resultate vir hierdie interaksie en metode nie gegenereer nie, maar l die fondasie vir
verdere werk aan ‘n PhD projek wat die verband tussen die twee interaksies en resultate kan wys.
Die belangrikheid van resultate hang af van hoe goed ander teoretiese benaderinge tot die
problem daardie resultate kan herproduseer en tot watter akkuraatheid. Vir modelle om geldig te
wees moet daar ook goeie ooreenkomste wees tussen teoretiese resultate en bekende
waarneembare eienskappe. In hierdie projek word sommige eieskappe van neutron sterre, soos
die toestandandsvergelyking, versadigingsdigtheid, bindingsenergie, simmetrie-energie, gradiënt
en onsaampersbaarheids parameters van die simmetrie-energie bestudeer. Die oorgangsdigtheid
word dan gevind deur gebruik te maak van die dinamiese metode. Resultate van die vyftien
Skyrme interaksie parameter stelle wys goeie ooreenstemming met die gepubliseerde waardes
van die eienskappe van neutron sterre en is konsistent met hulle empiriese waardes afgelei van
kern laboratorium data, wat die geldigheid van Skyrme interaksies vir die beskrywing van kernmaterie
bevestig.
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Cross sections and analysing power energy-sharing distributions of valence (p,2p)-knockout from 208Pb with a projectile of 200MeVBezuidenhout, Jacques 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT:
The aim of this work was to study the 208Pb(p,2p)207Tl quasi-free knockout process. The
experimental data were measured at the National Accelerator Centre using incident polarised
protons of 200 MeV. The two scattered particles, from the knockout reaction, were detected
in coincidence and their energies were determined using a magnetic spectrometer and a solid
state detector telescope.
Cross section and analysing power energy distributions were extracted from the experimental
measurements and these were compared with theoretical values for the Distorted Wave
Impulse Approximation. The theoretical cross-section calculations predict the experimental
cross-section distribution well for all combinations of distorting potentials and bound states
that were investigated, both with regard to shape, as well as absolute magnitude. However
the theoretical analysing power distributions did not agree with the experimental quantities.
Therefore it is not clear whether the analysing power is a useful tool to extract information on
the specifics of the quasi-free reaction mechanism. The spectroscopic factors were found to
be consistent with the results obtained in previous studies, thereby inspiring confidence that
the problem with the analysing power distribution is not ascribable to a possible deficiency in
the experimental techniques exploited in this work. / AFRIKAANSE OPSOMMING:
Die doel van die studie was om die kwasi vrye 208pb(p,2p )207TI verstrooingsproses te
ondersoek. Die eksperimentele data is ingewin by die Nasionale Versnellingsentrum deur
gebruik te maak van 'n 200 MeV gepolariseerde proton bundel. Die twee verstrooide
deeltjies is in koïnsidens gemeet. Vir die metings is 'n magnetiese spektrometer en 'n
vastetoestand detektorteleskoop gebruik.
Die kansvlak- en analiseervermoë-energieverdelings is uit die eksperimentele data verkry en
is vergelyk met die berekenings van die Vervormde Golf Impuls Benadering. Die teoretiese
kansvlak berekening het die eksperimetele data goed voorspel, vir die verskillende
parametrisering van potensiaal en gebonde toestande. Die berekeninge het goed
ooreengestem met betrekking tot beide vorm en absolute grootheid. Die berekende
analiseervermoë het egter nie goed met die eksperimentele data ooreengestem nie. Dit is dus
nie duidelik of die analiseervermoë 'n handige instrument is om inligting oor die betrokke
kwasi-vrye reaksie meganisme te bekom nie. Die spektroskopiese faktore was in
ooreenstemming met resultate wat in vorige studies verkry is. Dit versterk vertroue dat die
probleem met die analiseervermoë nie toegeskryf kan word aan die eksperimentele tegniek
wat gebruik is nie.
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Non-linear effects in quantum electrodynamicsKohler, Shane Jerome 12 1900 (has links)
Thesis (MSc (Physics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: See abstract in full text / AFRIKAANSE OPSOMMING: Sien opsomming in volteks
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Additional degrees of freedom associated with position measurements in non-commutative quantum mechanicsRohwer, Christian M. 12 1900 (has links)
Thesis (MSc (Physics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Due to the minimal length scale induced by non-commuting co-ordinates, it is not clear a priori
what is meant by a position measurement on a non-commutative space. It was shown recently in
a paper by Scholtz et al. that it is indeed possible to recover the notion of quantum mechanical
position measurements consistently on the non-commutative plane. To do this, it is necessary to
introduce weak (non-projective) measurements, formulated in terms of Positive Operator-Valued
Measures (POVMs). In this thesis we shall demonstrate, however, that a measurement of position
alone in non-commutative space cannot yield complete information about the quantum state
of a particle. Indeed, the aforementioned formalism entails a description that is non-local in that
it requires knowledge of all orders of positional derivatives through the star product that is used
ubiquitously to map operator multiplication onto function multiplication in non-commutative
systems. It will be shown that there exist several equivalent local descriptions, which are arrived
at via the introduction of additional degrees of freedom. Consequently non-commutative quantum
mechanical position measurements necessarily confront us with some additional structure
which is necessary (in addition to position) to specify quantum states completely. The remainder
of the thesis, based in part on a recent publication (\Noncommutative quantum mechanics
{ a perspective on structure and spatial extent", C.M. Rohwer, K.G. Zloshchastiev,
L. Gouba and F.G. Scholtz, J. Phys. A: Math. Theor. 43 (2010) 345302) will involve
investigations into the physical interpretation of these additional degrees of freedom. For
one particular local formulation, the corresponding classical theory will be used to demonstrate
that the concept of extended, structured objects emerges quite naturally and unavoidably there.
This description will be shown to be equivalent to one describing a two-charge harmonically
interacting composite in a strong magnetic eld found by Susskind. It will be argued through
various applications that these notions also extend naturally to the quantum level, and constraints
will be shown to arise there. A further local formulation will be introduced, where the
natural interpretation is that of objects located at a point with a certain angular momentum
about that point. This again enforces the idea of particles that are not point-like. Both local
descriptions are convenient, in that they make explicit the additional structure which is encoded
more subtly in the non-local description. Lastly we shall argue that the additional degrees of
freedom introduced by local descriptions may also be thought of as gauge degrees of freedom in
a gauge-invariant formulation of the theory. / AFRIKAANSE OPSOMMING: As gevolg van die minimum lengteskaal wat deur nie-kommuterende ko ordinate ge nduseer word
is dit nie a priori duidelik wat met 'n posisiemeting op 'n nie-kommutatiewe ruimte bedoel word
nie. Dit is onlangs in 'n artikel deur Scholtz et al. getoon dat dit wel op 'n nie-kommutatiewe
vlak moontlik is om die begrip van kwantummeganiese posisiemetings te herwin. Vir hierdie
doel benodig ons die konsep van swak (nie-projektiewe) metings wat in terme van 'n positief
operator-waardige maat geformuleer word. In hierdie tesis sal ons egter toon dat 'n meting
van slegs die posisie nie volledige inligting oor die kwantumtoestand van 'n deeltjie in 'n niekommutatiewe
ruimte lewer nie. Ons formalisme behels 'n nie-lokale beskrywing waarbinne kennis
oor alle ordes van posisieafgeleides in die sogenaamde sterproduk bevat word. Die sterproduk
is 'n welbekende konstruksie waardeur operatorvermenigvuldiging op funksievermenigvuldiging
afgebeeld kan word. Ons sal toon dat verskeie ekwivalente lokale beskrywings bestaan wat volg
uit die invoer van bykomende vryheidsgrade. Dit beteken dat nie-kommutatiewe posisiemetings
op 'n natuurlike wyse die nodigheid van bykomende strukture uitwys wat noodsaaklik is om
die kwantumtoestand van 'n sisteem volledig te beskryf. Die res van die tesis, wat gedeeltelik
op 'n onlangse publikasie (\Noncommutative quantum mechanics { a perspective on
structure and spatial extent", C.M. Rohwer, K.G. Zloshchastiev, L. Gouba and F.G.
Scholtz, J. Phys. A: Math. Theor. 43 (2010) 345302) gebaseer is, behels 'n ondersoek
na die siese interpretasie van hierdie bykomende strukture. Ons sal toon dat vir 'n spesi eke
lokale formulering die beeld van objekte met struktuur op 'n natuurlike wyse in die ooreenstemmende
klassieke teorie na vore kom. Hierdie beskrywing is inderdaad ekwivalent aan die van
Susskind wat twee gelaaide deeltjies, gekoppel deur 'n harmoniese interaksie, in 'n sterk magneetveld
behels. Met behulp van verskeie toepassings sal ons toon dat hierdie interpretasie op
'n natuurlike wyse na die kwantummeganiese konteks vertaal waar sekere dwangvoorwaardes na
vore kom. 'n Tweede lokale beskrywing in terme van objekte wat by 'n sekere punt met 'n vaste
hoekmomentum gelokaliseer is sal ook ondersoek word. Binne hierdie konteks sal ons weer deur
die begrip van addisionele struktuur gekonfronteer word. Beide lokale beskrywings is gerie
ik
omdat hulle hierdie bykomende strukture eksplisiet maak, terwyl dit in die nie-lokale beskrywing
deur die sterproduk versteek word. Laastens sal ons toon dat die bykomende vryheidsgrade in
lokale beskrywings ook as ykvryheidsgrade van 'n ykinvariante formulering van die teorie beskou
kan word.
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Self-organised criticality and seismicityBoonzaaier, Leandro 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: In this thesis we give an overview of self-organised criticality and its application to studying
seismicity. We recall some of the basic models and techniques for studying self-organised critical
systems. We discuss one of these, the sandpile model, in detail and show how various properties
of the model can be calculated using a matrix formulation thereof. A correspondence between
self-organised critical systems and seismicity is then proposed. Finally, we consider the timeevolution
of the sandpile model by using a time-to-failure analysis, originally developed in the
study of seismicity and obtain results for the sandpile model that show similarities with that of
the analyses of seismic data. / AFRIKAANSE OPSOMMING: In hierdie tesis gee ons 'n oorsig van self-organiserende kritikaliteit en die toepassing daarvan
in die studie van seismisiteit. Ons beskryf die basiese modelle en tegnieke vir die studie van
self-organiserende kritiese sisteme. Ons bespreek een van hierdie, die sandhoopmodel, in besonderheid
en wys hoe om verskeie eienskappe van die model te bereken deur gebruik te maak van 'n
matriks-formulering daarvan. Ons stel dan 'n korrespondensie tussen self-organiserende kritiese
sisteme en seismisiteit voor. Ter afsluiting ondersoek ons die tydontwikkeling van die sand hoopmodel
deur gebruik te maak van 'n deurbreektyd analise wat oorspronklik in die bestudering seismiese
data ontwikkel is. Die resultate vir die analise van die sandhoopmodel toon ooreenkomste
met dit wat verkry word vir seismiese data.
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Development and optimisation of a solid-state pulsed power supply for a CO₂ TEA laserStehmann, Timo 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: With technological advances in solid-state switches the modernization of conventional pulsed
power supplies utilizing thyratrons has become possible. A novel pulsed power supply is designed
where two series-stacked IGBTs (rated at 1700 V and 300 A each) are used to replace a thryatrondriven
pulsed power supply for a mini CO2 TEA laser.
The mini CO2 TEA laser is firstly characterized in order to optimize the design of the pulsed power
supply. It is found that stable laser discharges can be obtained with electrode voltage rise-times of
150 ns or less. Furthermore, the optical output energy and the efficiency of the laser have been
significantly increased by reducing the peaking capacitor size of the pulsed power supply.
The two stacked IGBTs switch a C-C transfer loop and the generated pulse is stepped up by a pulse
transformer and is compressed by a two-stage magnetic pulse compression unit. Theoretically and
through measurements it is shown that automatic voltage sharing between the two IGBTs can be
obtained if the turn-on time of the IGBTs is much faster than the transfer time of the switched C-C
transfer loop. Lifetime tests reveal that high-power IGBTs are able to reliably switch pulses with
peak currents between 4 and 5 times the rated average current of the device. Under laser fault
conditions, i.e. laser arcing or missing laser discharges, the reliability of the pulser can be increased
by using over-voltage snubbers. In addition, it was found that the internal diode of IGBT modules
can eventually fail under the prevalence of laser fault conditions.
A modular construction approach is used where components of the pulsed power supply are preassembled.
A new rectangular layout of the magnetic pulse compression unit is utilized in order to
minimize size and simplify the final construction and assembly. / AFRIKAANSE OPSOMMING: Nuwe ontwikkeling in vastetoestand-skakelaars het die modernisering van laser-pulskragbronne
moontlik gemaak. ’n Nuwe kragbron wat gebruik maak van twee seriegeskakelde IGBT’s is
ontwerp om ’n Tiratron-gedrewe laserkragbron te vervang, wat vir ’n mini-C02-TEA-laser gebruik
word.
Die laser is vooraf eers gekarakteriseer om sodoende die laserkragbron te optimeer. Daar is bevind
dat stabiele laserontladings verkry kan word met spanningstygtye van 150 ns of minder. Verder kan
die uittree-energie van die laser beduidend verhoog word deur die uittreekapasitore (eng.: peaking
capacitors) van die laserkragbron te verminder.
Die twee serie-geskakelde IGBT’s skakel ’n C-C oordraglus. Die spanning van die gegenereerde
puls word deur ’n pulstransformator verhoog en die stygtyd van die puls word met ’n twee-stadium
magnetiese pulskompressor verlaag. Teoreties en deur metings kan getoon word dat eweredige
spanningsverdeling tussen die twee IGBT’s outomaties verkry kan word indien die skakeltye van
die IGBT’s baie vinniger as die oordragstyd van die C-C oordraglus is. Toetse het getoon dat
IGBT’s pulse met piekstrome van tussen vier tot vyf keer die gespesifiseerde gemiddelde stroom
betroubaar kan skakel. Tydens laserfouttoestande kan die betroubaarheid van die IGBT verhoog
word deur oorspanningsgapsers te gebruik, maar onder fouttoestande wat voortduur, kan die IGBT
se interne diode vemietig word.
Die komponente van die laserkragbron is as modules vervaardig, wat op ’n maklike wyse
gemonteer kan word. ’n Nuwe reghoekige uitleg is gebruik vir die konstruksie van die magnetiese
pulskompressor, waarmee die grootte van die pulskompressor geminimeer en die konstruksie
vergemaklik is.
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Characterization of thulium doped fiber for mid infrared laser applicationsNdebeka, Wilfrid Innocent 03 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2011. / Please refer to full text to view abstract.
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Flattened Gaussian beam for laser paint removalDu Preez, Neil Carl 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Lasers are commonly used in the industry for various applications such as laser cutting, laser drilling, lithography, medical applications, surface cleaning and a myriad of other applications. In any application of a laser the beam properties are significant. In the paint removal application discussed in this thesis, the beam properties of the laser beam can have a large impact on the efficiency of the paint removal process. The pulse energy or the average output power of the laser is normally an important parameter in laser materials processing applications. The spatial profile or intensity distribution of the beam also has an influence on the process. The propagation of the laser beam from the laser to the working point is also significant in applying the laser beam to the material. In the ideal scenario one would like to control all the parameters of the laser in terms of the output, in energy or output power, the propagation of the laser beam and the intensity distribution of the beam.
The process of laser-based paint removal is no different to this. In this process a TEA CO2 laser is used for the ablation of paint from a substrate. In this application high pulse energy is required from the laser together with good beam propagation properties for delivery of the beam over a long distance. For this application the multimode beam of the TEA CO2 laser can be applied for the paint removal. The multimode beam has sufficiently high pulse energy for the paint removal process, but is not suitable for propagating over long distances through a beam path with a finite aperture. Furthermore the multimode beam does not have a uniform energy intensity distribution. It would therefore be ideal if the TEA CO2 laser could be designed with a custom beam that has a uniform intensity distribution, high pulse energy and good beam propagation.
These requirements lead to the study of flattened irradiance profile laser beams. In this thesis flattened irradiance profile beams in the form of Flattened Gaussian beams are investigated. The theory of the Flattened Gaussian profile as well as the propagation of the beam is investigated. Furthermore the generation of such a beam internally to the laser resonator is studied. In succession to this a custom laser resonator was designed and implemented on the TEA CO2 laser. The resulting Flattened Gaussian Beam was characterised and applied to the application of laser paint removal. It was finally shown that the Flattened Gaussian Beam could be successfully generated and applied with equal success in the application of laser paint removal. / AFRIKAANSE OPSOMMING: Lasers word algemeen in die industrie gebruik vir toepassings soos laser snywerk, laser boorwerk, litografie, mediese toepassings, oppervlakreiniging en verskeie ander. In enige toepassing van 'n laser is die eienskappe van die laserbundel van groot belang vir die proses. In die verf verwydering toepassing wat bespreek word in hierdie tesis het die bundel eienskappe 'n groot invloed op die effektiwiteit van die verf stropings proses. Die pulsenergie of uitset drywing van die laser is gewoonlik 'n belangrike parameter in 'n materiaalverwerkings toepassing. Die ruimtelike profiel of energie intensiteitprofiel van die bundel het ook 'n invloed op die proses. Die voortplanting van die bundel vanaf die laser na die werkspunt het ook 'n beduidende invloed op die toepassing van die laserbundel op die materiaal. In die ideale geval sal mens graag al die parameters van die laserbundel soos pulsenergie of drywing, die bundel voortplanting en energie intensiteitprofiel wil beheer.
Die toepassing van die laser vir verfverwydering vereis ook die beheer van hierdie unieke parameters wat reeds genoem is. In hierdie proses is 'n TEA CO2 laser gebruik vir die verwydering van verf van 'n substraat. Die toepassing vereis hoë pulsenergie saam met goeie bundel voortplantingseienskappe vir lewering van die bundel oor lang afstande. Die multimode bundel van die laser kan gebruik word vir hierdie toepassing. Die multimode bundel bevat genoegsame energie vir die verfstropings proses maar is nie geskik vir voortplanting oor lang afstande deur 'n bundelpad wat 'n beperking op die bundel grootte het nie. Verder het die multimode bundel ook nie 'n uniforme energie intensiteitprofiel nie. Dit sou ideal wees as die TEA CO2 laser toegerus kon word met 'n toepassingsgerigte bundel wat hoë puls energie, goeie bundel voortplanting en 'n uniforme intensiteitprofiel het.
Hierdie vereiste het gelei tot die studie van laserbundels met 'n uniforme plat energie intensiteitprofiel. In hierdie tesis word plat intensiteit bundels in die vorm van plat Gaussiese bundels ondersoek. Die teorie van plat Gaussiese bundels sowel as die voortplanting van hierdie bundels word hier ondersoek. Verder word die opwekking van hierdie bundels intern tot die laserresonator ook ondersoek. Na die ondersoek is daar oorgegaan in die ontwerp en implementering van 'n doelgemaakte resonator op 'n TEA CO2 laser. Die resonator het 'n plat Gaussiese bundel as uitset gelewer. Die bundel was gevolglik gekarakteriseer en aangewend in 'n
verfstropings toepassing. Ten einde is daar getoon dat 'n plat Gaussiese bundel suksesvol opgewek en toegepas kon word.
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