Automatization of TDS data evaluation

Tato práce se zabývá automatizací vyhodnocování dat termální desorpční spektroskopie (TDS). Teoretická část pojednává o procesích adsorpce a desorpce atomů a molekul a teplotní závislosti desorpce. Součástí práce je také kvantitativní analýza signálu měřícího přístroje. Hlavním cílem praktické části bylo vytvoření počítačového programu na automatizaci vyhodnocování dat TDS. Popis programu a uživatelská příručka jsou také součástí práce. Proběhlo testování programu na předchozích měření a kinetické parametry desorpce byly zjištěny u několika vzorků.This bachelor thesis is focused on automatization of post-processing and evaluation of thermal desorption spectroscopy (TDS) data. The theoretical part discusses the processes of adsorption and desorption of atoms and molecules on surfaces and the thermal dependence of the latter. This work also provides a quantitative analysis of the measured signal from the instrument. The main objective of the practical part is to create a computer tool for automatization of TDS data evaluation. Description of the program, as well as a user guide, is included in the work. Comprehensive tests of the created program were concluded on previously measured TDS spectra and the kinetic parameters of several samples were determined.

Electrostatic Deflection and Correction Systems

Tato diplomová práce se věnuje prozkoumání možností dynamické korekce vad v elektronové litografii. Pro výpočty byl zvolen elektronový litograf BS600. Práce se zabývá korekcí vad vychýlení třetího řádu: zklenutí pole, astigmatismu a zkreslení. Aberace byly spočteny jak pro současný magnetický vychyolvací systém, tak pro nově navržený elektrostatický deflektor. Vlastnosti a vady obou vychylovacích a korekčních systémů byly porovnány.The aim of this master's thesis is to explore and study dynamic aberration correction options in electron-beam lithography systems. For the calculations, the thesis uses the optical column of the BS600 electron-beam writer. The thesis focuses on corrections of the third order field curvature, astigmatism, and distortion aberrations of the currently used magnetic deflection system and a newly designed electrostatic deflection system. The parameters of the two deflection and correction systems were compared.

Parasitic Aberrations of Electrostatic Deflectors

Tato disertační práce se zabývá parazitickými aberacemi elektrostatických multipólových optických prvků vznikajícími v důsledku nepřesného seřízení elektrod. Přesnost výroby a seřízení mechanických částí může mít významný vliv na rozlišení elektronových mikroskopů a litografických systémů. Nepřesnosti výroby, chyby justáže a všechna další narušení symetrie generují takzvaná parazitická pole, jejichž účinky na elektronový svazek se označují jako vady seřízení. Poruchy osově souměrných čoček se obvykle řeší pomocí Sturrockova principu. Posunutí nebo naklonění celých multipólových prvků lze analyzovat v globálně posunutém nebo nakloněném souřadnicovém systému. Tato práce se zabývá vadami seřízení jednotlivých elektrod, které nelze jednoduše popsat zmíněnými přístupy, a obvykle je potřeba je řešit ve 3D. Výpočty ve 3D jsou obecně pomalejší a mají vyšší výpočetní nároky než 2D nástroje standardně používané v softwaru pro částicovou optiku. Pro výpočet parazitických polí generovaných nesprávně seřízenými elektrodami byla v této práci vyvinuta 2D perturbační metoda, kompatibilní s metodou konečných prvků, založená na lokálním posunutí souřadného systému u perturbované elektrody. Byly studovány nepřesnosti vzniklé posuvem elektrody v každé ose cylindrického souřadného systému (podélné, radiální a azimutální). Dále byly ukázány možné aplikace odvozené obecné metody, např. elipticita a příčný posun celého deflektoru. Pro každý z těchto případů jsou výsledné parazitické osové potenciály vypočítané 2D metodou a porovnány s 3D řešením. Kromě srovnání parazitických osových potenciálů byl také ukázán vliv vad seřízení na stopu elektronového svazku procházející optickou soustavou elektronového litografu. Ověření 3D výpočtem bylo v dobré shodě s 2D metodou. Navržený způsob výpočtu parazitických polí ve 2D umožňuje porozumět vlivům různých výrobních a montážních tolerancí, charakterizovat tyto vlivy, navrhnout zařízení potřebná pro korekci vzniklých aberací a optimalizovat požadavky na mechanické tolerance. Vyvinutá metoda je použitelná na jakémkoli standardním PC a je o 1--2 řády rychlejší než řešení porušeného systému ve 3D.The present doctoral dissertation deals with parasitic aberrations in electrostatic multipole optical components arising due to mechanical misalignment of the electrodes. Manufacturing and alignment precision of the mechanical parts can have a significant influence on the performance of electron beam machines such as microscopes and lithography (EBL) systems. Defects, imprecisions, and all other symmetry violations generate so-called parasitic fields whose effects on the particle beam are referred to as parasitic aberrations. Perturbations of axially symmetric lenses are usually treated using Sturrock's principle. Displacement or tilt of an entire multipole component can be analyzed in a globally shifted or tilted coordinate system. The present thesis deals with the misalignment of individual electrodes, which cannot be easily described with the mentioned approaches and usually need to be solved in 3D. Calculations in 3D are generally slower and have higher computational requirements than 2D tools standardly used in charged particle optics programs. To calculate parasitic fields generated by electrode misalignment, a 2D perturbation method compatible with the finite element method (FEM) has been developed in this thesis based on shifting the coordinate system locally around the affected electrode. Electrodes misaligned in each axis of the cylindrical coordinate system (longitudinal, radial, and azimuthal) are studied. Possible applications of the derived general method are shown, such as ellipticity and transverse shift of the entire deflector. For each of these cases, the resulting parasitic axial field functions (AFF) calculated in 2D are validated against the 3D solution. In addition to comparing parasitic AFFs, a case study is provided where the effect of parasitic aberrations on the electron beam in an entire optical column of an EBL system is shown, again validated against the 3D solution. The proposed method of calculating parasitic fields in 2D allows understanding the effects of different manufacturing and assembling tolerances, characterizing these effects, designing aberration correction devices, and optimizing mechanical tolerance requirements. The developed method can be run on any standard PC and is 1--2 orders of magnitude faster than solving the perturbed system in 3D.

State of the climate in 2022: introduction

Earth’s global climate system is vast, complex, and intricately interrelated. Many areas are influenced by global-scale phenomena, including the “triple dip” La Niña conditions that prevailed in the eastern Pacific Ocean nearly continuously from mid-2020 through all of 2022; by regional phenomena such as the positive winter and summer North Atlantic Oscillation that impacted weather in parts the Northern Hemisphere and the negative Indian Ocean dipole that impacted weather in parts of the Southern Hemisphere; and by more localized systems such as high-pressure heat domes that caused extreme heat in different areas of the world. Underlying all these natural short-term variabilities are long-term climate trends due to continuous increases since the beginning of the Industrial Revolution in the atmospheric concentrations of Earth’s major greenhouse gases.In 2022, the annual global average carbon dioxide concentration in the atmosphere rose to 417.1±0.1 ppm, which is 50% greater than the pre-industrial level. Global mean tropospheric methane abundance was 165% higher than its pre-industrial level, and nitrous oxide was 24% higher. All three gases set new record-high atmospheric concentration levels in 2022.Sea-surface temperature patterns in the tropical Pacific characteristic of La Niña and attendant atmospheric patterns tend to mitigate atmospheric heat gain at the global scale, but the annual global surface temperature across land and oceans was still among the six highest in records dating as far back as the mid-1800s. It was the warmest La Niña year on record. Many areas observed record or near-record heat. Europe as a whole observed its second-warmest year on record, with sixteen individual countries observing record warmth at the national scale. Records were shattered across the continent during the summer months as heatwaves plagued the region. On 18 July, 104 stations in France broke their all-time records. One day later, England recorded a temperature of 40°C for the first time ever. China experienced its second-warmest year and warmest summer on record. In the Southern Hemisphere, the average temperature across New Zealand reached a record high for the second year in a row. While Australia’s annual temperature was slightly below the 1991–2020 average, Onslow Airport in Western Australia reached 50.7°C on 13 January, equaling Australia's highest temperature on record.While fewer in number and locations than record-high temperatures, record cold was also observed during the year. Southern Africa had its coldest August on record, with minimum temperatures as much as 5°C below normal over Angola, western Zambia, and northern Namibia. Cold outbreaks in the first half of December led to many record-low daily minimum temperature records in eastern Australia.The effects of rising temperatures and extreme heat were apparent across the Northern Hemisphere, where snow-cover extent by June 2022 was the third smallest in the 56-year record, and the seasonal duration of lake ice cover was the fourth shortest since 1980. More frequent and intense heatwaves contributed to the second-greatest average mass balance loss for Alpine glaciers around the world since the start of the record in 1970. Glaciers in the Swiss Alps lost a record 6% of their volume. In South America, the combination of drought and heat left many central Andean glaciers snow free by mid-summer in early 2022; glacial ice has a much lower albedo than snow, leading to accelerated heating of the glacier. Across the global cryosphere, permafrost temperatures continued to reach record highs at many high-latitude and mountain locations.In the high northern latitudes, the annual surface-air temperature across the Arctic was the fifth highest in the 123-year record. The seasonal Arctic minimum sea-ice extent, typically reached in September, was the 11th-smallest in the 43-year record; however, the amount of multiyear ice—ice that survives at least one summer melt season—remaining in the Arctic continued to decline. Since 2012, the Arctic has been nearly devoid of ice more than four years old.In Antarctica, an unusually large amount of snow and ice fell over the continent in 2022 due to several landfalling atmospheric rivers, which contributed to the highest annual surface mass balance, 15% to 16% above the 1991–2020 normal, since the start of two reanalyses records dating to 1980. It was the second-warmest year on record for all five of the long-term staffed weather stations on the Antarctic Peninsula. In East Antarctica, a heatwave event led to a new all-time record-high temperature of −9.4°C—44°C above the March average—on 18 March at Dome C. This was followed by the collapse of the critically unstable Conger Ice Shelf. More than 100 daily low sea-ice extent and sea-ice area records were set in 2022, including two new all-time annual record lows in net sea-ice extent and area in February.Across the world’s oceans, global mean sea level was record high for the 11th consecutive year, reaching 101.2 mm above the 1993 average when satellite altimetry measurements began, an increase of 3.3±0.7 over 2021. Globally-averaged ocean heat content was also record high in 2022, while the global sea-surface temperature was the sixth highest on record, equal with 2018. Approximately 58% of the ocean surface experienced at least one marine heatwave in 2022. In the Bay of Plenty, New Zealand’s longest continuous marine heatwave was recorded.A total of 85 named tropical storms were observed during the Northern and Southern Hemisphere storm seasons, close to the 1991–2020 average of 87. There were three Category 5 tropical cyclones across the globe—two in the western North Pacific and one in the North Atlantic. This was the fewest Category 5 storms globally since 2017. Globally, the accumulated cyclone energy was the lowest since reliable records began in 1981. Regardless, some storms caused massive damage. In the North Atlantic, Hurricane Fiona became the most intense and most destructive tropical or post-tropical cyclone in Atlantic Canada’s history, while major Hurricane Ian killed more than 100 people and became the third costliest disaster in the United States, causing damage estimated at $113 billion U.S. dollars. In the South Indian Ocean, Tropical Cyclone Batsirai dropped 2044 mm of rain at Commerson Crater in Réunion. The storm also impacted Madagascar, where 121 fatalities were reported.As is typical, some areas around the world were notably dry in 2022 and some were notably wet. In August, record high areas of land across the globe (6.2%) were experiencing extreme drought. Overall, 29% of land experienced moderate or worse categories of drought during the year. The largest drought footprint in the contiguous United States since 2012 (63%) was observed in late October. The record-breaking megadrought of central Chile continued in its 13th consecutive year, and 80-year record-low river levels in northern Argentina and Paraguay disrupted fluvial transport. In China, the Yangtze River reached record-low values. Much of equatorial eastern Africa had five consecutive below-normal rainy seasons by the end of 2022, with some areas receiving record-low precipitation totals for the year. This ongoing 2.5-year drought is the most extensive and persistent drought event in decades, and led to crop failure, millions of livestock deaths, water scarcity, and inflated prices for staple food items.In South Asia, Pakistan received around three times its normal volume of monsoon precipitation in August, with some regions receiving up to eight times their expected monthly totals. Resulting floods affected over 30 million people, caused over 1700 fatalities, led to major crop and property losses, and was recorded as one of the world’s costliest natural disasters of all time. Near Rio de Janeiro, Brazil, Petrópolis received 530 mm in 24 hours on 15 February, about 2.5 times the monthly February average, leading to the worst disaster in the city since 1931 with over 230 fatalities.On 14–15 January, the Hunga Tonga-Hunga Ha'apai submarine volcano in the South Pacific erupted multiple times. The injection of water into the atmosphere was unprecedented in both magnitude—far exceeding any previous values in the 17-year satellite record—and altitude as it penetrated into the mesosphere. The amount of water injected into the stratosphere is estimated to be 146±5 Terragrams, or ∼10% of the total amount in the stratosphere. It may take several years for the water plume to dissipate, and it is currently unknown whether this eruption will have any long-term climate effect