Technology is the collection of techniques, skills and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques and the like, or it can be embedded in machines to allow for operation without detailed knowledge of their workings. Systems applying technology by taking an input, changing it according to the system's use, producing an outcome are referred to as technology systems or technological systems; the simplest form of technology is the use of basic tools. The prehistoric discovery of how to control fire and the Neolithic Revolution increased the available sources of food, the invention of the wheel helped humans to travel in and control their environment. Developments in historic times, including the printing press, the telephone, the Internet, have lessened physical barriers to communication and allowed humans to interact on a global scale. Technology has many effects, it has allowed the rise of a leisure class.
Many technological processes produce unwanted by-products known as pollution and deplete natural resources to the detriment of Earth's environment. Innovations have always influenced the values of a society and raised new questions in the ethics of technology. Examples include the rise of the notion of efficiency in terms of human productivity, the challenges of bioethics. Philosophical debates have arisen over the use of technology, with disagreements over whether technology improves the human condition or worsens it. Neo-Luddism, anarcho-primitivism, similar reactionary movements criticize the pervasiveness of technology, arguing that it harms the environment and alienates people; the use of the term "technology" has changed over the last 200 years. Before the 20th century, the term was uncommon in English, it was used either to refer to the description or study of the useful arts or to allude to technical education, as in the Massachusetts Institute of Technology; the term "technology" rose to prominence in the 20th century in connection with the Second Industrial Revolution.
The term's meanings changed in the early 20th century when American social scientists, beginning with Thorstein Veblen, translated ideas from the German concept of Technik into "technology." In German and other European languages, a distinction exists between technik and technologie, absent in English, which translates both terms as "technology." By the 1930s, "technology" referred not only to the study of the industrial arts but to the industrial arts themselves. In 1937, the American sociologist Read Bain wrote that "technology includes all tools, utensils, instruments, clothing and transporting devices and the skills by which we produce and use them." Bain's definition remains common among scholars today social scientists. Scientists and engineers prefer to define technology as applied science, rather than as the things that people make and use. More scholars have borrowed from European philosophers of "technique" to extend the meaning of technology to various forms of instrumental reason, as in Foucault's work on technologies of the self.
Dictionaries and scholars have offered a variety of definitions. The Merriam-Webster Learner's Dictionary offers a definition of the term: "the use of science in industry, etc. to invent useful things or to solve problems" and "a machine, piece of equipment, etc., created by technology." Ursula Franklin, in her 1989 "Real World of Technology" lecture, gave another definition of the concept. The term is used to imply a specific field of technology, or to refer to high technology or just consumer electronics, rather than technology as a whole. Bernard Stiegler, in Technics and Time, 1, defines technology in two ways: as "the pursuit of life by means other than life," and as "organized inorganic matter."Technology can be most broadly defined as the entities, both material and immaterial, created by the application of mental and physical effort in order to achieve some value. In this usage, technology refers to tools and machines that may be used to solve real-world problems, it is a far-reaching term that may include simple tools, such as a crowbar or wooden spoon, or more complex machines, such as a space station or particle accelerator.
Tools and machines need not be material. W. Brian Arthur defines technology in a broad way as "a means to fulfill a human purpose."The word "technology" can be used to refer to a collection of techniques. In this context, it is the current state of humanity's knowledge of how to combine resources to produce desired products, to solve problems, fulfill needs, or satisfy wants; when combined with another term, such as "medical technology" or "space technology," it refers to the state of the respective field's knowledge and tools. "State-of-the-art technology" refers to the high technology available to humanity in any field. Technology can be viewed as an activity that changes culture. Additionally, technology is the application of math, science, an
Johannes Wilhelm "Hans" Geiger was a German physicist. He is best known as the co-inventor of the detector component of the Geiger counter and for the Geiger–Marsden experiment which discovered the atomic nucleus, he was the brother of climatologist Rudolf Geiger. Geiger was born at Neustadt Germany, he was one of five children born to the Indologist Wilhelm Ludwig Geiger, a professor at the University of Erlangen. In 1902, Geiger started studying physics and mathematics at the University of Erlangen and was awarded a doctorate in 1906, his thesis was on electrical discharges through gases. He received a fellowship to the University of Manchester and worked as an assistant to Arthur Schuster. In 1907, after Schuster's retirement, Geiger began to work with his successor, Ernest Rutherford, in 1908, along with Ernest Marsden, conducted the famous Geiger–Marsden experiment; this process allowed them to count alpha particles and led to Rutherford's winning the 1908 Nobel Prize in Chemistry. In 1911 Geiger and John Mitchell Nuttall discovered the Geiger–Nuttall law and performed experiments that led to Rutherford's atomic model.
In 1912, Geiger was named head radiation research at the German National Institute of Science and Technology in Berlin. There he worked with James Chadwick. Work was interrupted when Geiger served in the German military during World War I as an artillery officer from 1914 to 1918. In 1924, Geiger used his device to confirm the Compton effect which helped earn Arthur Compton the 1927 Nobel Prize in Physics. In 1925, he began a teaching position at the University of Kiel where, in 1928 Geiger and his student Walther Müller created an improved version of the Geiger tube, the Geiger–Müller tube; this new device not only detected alpha particles, but beta and gamma particles as well, is the basis for the Geiger counter. In 1929 Geiger was named professor of physics and director of research at the University of Tübingen where he made his first observations of a cosmic ray shower. In 1936 he took a position with the Technische Universität Berlin where he continued to research cosmic rays, nuclear fission, artificial radiation until his death in 1945.
Beginning in 1939, after the discovery of atomic fission, Geiger was a member of the Uranium Club, the German investigation of nuclear weapons during World War II. The group splintered in 1942 after it was incorrectly determined that nuclear weapons would not play a major role in ending the war. Although Geiger signed a petition against the Nazi government's interference with universities, he provided no support to colleague Hans Bethe when he was fired for being Jewish. Geiger died in Potsdam, two months after the first nuclear bomb exploded over Japan. Geiger Geiger tube telescope Brief biographical material Annotated bibliography for Hans Geiger from the Alsos Digital Library for Nuclear Issues
Supersaturation is a solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances. It can refer to a vapor of a compound that has a higher pressure than the vapor pressure of that compound. Special conditions need to be met in order to generate a supersaturated solution. One of the easiest ways to do this relies on the temperature dependence of solubility; as a general rule, the more heat is added to a system, the more soluble a substance becomes.. Therefore, at high temperatures, more solute can be dissolved than at lower temperatures. If this solution were to be cooled at a rate faster than the rate of precipitation, the solution will become supersaturated until the solute precipitates to the temperature-determined saturation point; the precipitation or crystallization of the solute takes longer than the actual cooling time because the molecules need to meet up and form the precipitate without being knocked apart by water. Thus, the larger the molecule, the longer the solute will take to crystallize due to the principles of Brownian motion.
The condition of supersaturation does not have to be reached through the manipulation of heat. The ideal gas law suggests that pressure and volume can be changed to force a system into a supersaturated state. If the volume of solvent is decreased, the concentration of the solute can be above the saturation point and thus create a supersaturated solution; the decrease in volume is most generated through evaporation. An increase in pressure can drive a solution to a supersaturated state. All three of these mechanisms rely on the fact that the conditions of the solution can be changed quicker than the solute can precipitate or crystallize out. Supersaturated solutions will undergo crystallization under specific conditions. In a normal solution, once the maximum amount of solute is dissolved, adding more solute would either cause the dissolved solute to precipitate out and/or for the solute to not dissolve at all. There are cases wherein solubility of a saturated solution is decreased by manipulating temperature, pressure, or volume but a supersaturated state does not occur.
In these cases, the solute will precipitate out. This is. A supersaturated solution of gases in a liquid may form bubbles. Supersaturation may be defined as a sum of all gas partial pressures in the liquid which exceeds the ambient pressure in the liquid. Crystallization will occur to allow the solution to reach a lower energy state.. The activation energy comes in the form of a nuclei crystal being added to the liquid solution; this nuclei can be either added from another source, known as seeding, or can spontaneously form within the solution due to ion and molecule interactions. This process is known as primary nucleation, it is necessary for the nuclei to be identical to the solute, crystallizing. This will allow for the dissolved ions to build up on the nuclei and each other in the process of crystal growth or secondary nucleation. There are a multitude of factors that will affect the rate and order of magnitude with which crystallization proceeds as well as the difference in formation of crystallites and single crystals.
A crystallization phase diagram shows where undersaturation and supersaturation occur at certain concentrations. Concentrations below the solubility curve result in an undersaturation solution. Saturation occurs. If the concentrations are above the solubility curve, the solution is considered supersaturated. There are three mechanisms with which supersaturation occurs: precipitation and metastable. In the precipitation zone, the molecules in a solution are in excess and will separate from the solution to form amorphous aggregates; the excess of molecules aggregate to form a crystalline structure. In the metastable zone, the solution takes time to nucleate. In order to grow crystals while in the metastable zone, the conditions would require the formation of one nucleus while in the nucleation zone, just past the metastable region; the supersaturated solution can return to the metastable region. Supersaturation in vapor phase is related to the surface tension of liquids through the Kelvin equation, the Gibbs–Thomson effect and the Poynting effect.
The International Association for the Properties of Water and Steam provides a special equation for the Gibbs free energy in the metastable-vapor region of water in its Revised Release on the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of Water and Steam. All thermodynamic properties for the metastable-vapor region of water can be derived from this equation by means of the appropriate relations of thermodynamic properties to the Gibbs free energy. Table 1. Supersaturation measurement methods. Supersaturation has been a frequent topic of research throughout history. Early studies of these solutions were conducted with sodium sulfate known as Glauber’s Salt, due to the stability of the crystal and the rising role it had in industry. Through the use of this salt, an important scientific discovery was made by Jean-Baptiste Ziz, a botanist from Mayence, in 1809, his experiments allowed him to conclude that the crystallization of a supersaturated solution does not come from its agitation, but from solid matter entering and acting as a “starting” site for crystals to form
A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in 1929-1930 at the University of California and patented in 1932. A cyclotron accelerates charged particles outwards from the center along a spiral path; the particles are held to a spiral trajectory by a static magnetic field and accelerated by a varying electric field. Lawrence was awarded the 1939 Nobel prize in physics for this invention. Cyclotrons were the most powerful particle accelerator technology until the 1950s when they were superseded by the synchrotron, are still used to produce particle beams in physics and nuclear medicine; the largest single-magnet cyclotron was the 4.67 m synchrocyclotron built between 1940 and 1946 by Lawrence at the University of California at Berkeley, which could accelerate protons to 730 million electron volts. The largest cyclotron is the 17.1 m multimagnet TRIUMF accelerator at the University of British Columbia in Vancouver, British Columbia which can produce 500 MeV protons.
Over 1200 cyclotrons are used in nuclear medicine worldwide for the production of radionuclides. The first cyclotron was developed and patented by Ernest Lawrence in 1932 at the University of California, Berkeley, he used large electromagnets recycled from obsolete Poulsen arc radio transmitters provided by the Federal Telegraph Company. A graduate student, M. Stanley Livingston, did much of the work of translating the idea into working hardware. Lawrence read an article about the concept of a drift tube linac by Rolf Widerøe, working along similar lines with the betatron concept. At the Radiation Laboratory of the University of California at Berkeley Lawrence constructed a series of cyclotrons which were the most powerful accelerators in the world at the time, he developed a 467 cm synchrocyclotron. Lawrence received the 1939 Nobel prize in physics for this work; the first European cyclotron was constructed in Leningrad in the physics department of the Radium Institute, headed by Vitaly Khlopin.
This Leningrad instrument was first proposed in 1932 by George Gamow and Lev Mysovskii and was installed and became operative by 1937. In Nazi Germany a cyclotron was built in Heidelberg under supervision of Walther Bothe and Wolfgang Gentner, with support from the Heereswaffenamt, became operative in 1943. A cyclotron accelerates a charged particle beam using a high frequency alternating voltage, applied between two hollow "D"-shaped sheet metal electrodes called "dees" inside a vacuum chamber; the dees are placed face to face with a narrow gap between them, creating a cylindrical space within them for the particles to move. The particles are injected into the center of this space; the dees are located between the poles of a large electromagnet which applies a static magnetic field B perpendicular to the electrode plane. The magnetic field causes the particles' path to bend in a circle due to the Lorentz force perpendicular to their direction of motion. If the particles' speeds were constant, they would travel in a circular path within the dees under the influence of the magnetic field.
However a radio frequency alternating voltage of several thousand volts is applied between the dees. The voltage creates an oscillating electric field in the gap between the dees that accelerates the particles; the frequency is set. To achieve this, the frequency must match the particle's cyclotron resonance frequency f = q B 2 π m,where B is the magnetic field strength, q is the electric charge of the particle and m is the relativistic mass of the charged particle; each time after the particles pass to the other dee electrode the polarity of the RF voltage reverses. Therefore, each time the particles cross the gap from one dee electrode to the other, the electric field is in the correct direction to accelerate them; the particles' increasing speed due to these pushes causes them to move in a larger radius circle with each rotation, so the particles move in a spiral path outward from the center to the rim of the dees. When they reach the rim a small voltage on a metal plate deflects the beam so it exits the dees through a small gap between them, hits a target located at the exit point at the rim of the chamber, or leaves the cyclotron through an evacuated beam tube to hit a remote target.
Various materials may be used for the target, the nuclear reactions due to the collisions will create secondary particles which may be guided outside of the cyclotron and into instruments for analysis. The cyclotron was the first "cyclical" accelerator; the advantage of the cyclotron design over the existing "electrostatic" accelerators of the time such as the Cockcroft-Walton accelerator and Van de Graaff generator, was that in these machines the particles were only accelerated once by the voltage, so the particles' energy was equal to the accelerating voltage on the machine, limited by air breakdown to a few million volts. In the cyclotron, in contrast, the particles encounter the accelerating voltage many times during their spiral path, so are accelerated many times, so the output energy can be many times the accelerating voltage. Since the particles are accelerated by the voltage many times, the final energy of the particles is not dependent on the accelerating voltage but on the strength of the magnetic field and the diameter of the accelerating chamber, the dees.
Cyclotrons can only accelerate particles to speeds much slower than the speed of light, nonrelativistic sp
Donald A. Glaser
Donald Arthur Glaser was an American physicist and the winner of the 1960 Nobel Prize in Physics for his invention of the bubble chamber used in subatomic particle physics. Born in Cleveland, Glaser completed his Bachelor of Science degree in physics and mathematics from Case School of Applied Science in 1946, he completed his Ph. D. in physics from the California Institute of Technology in 1949. Glaser accepted a position as an instructor at the University of Michigan in 1949, was promoted to professor in 1957, he joined the faculty of the University of California at Berkeley, in 1959, as a Professor of Physics. During this time his research concerned short-lived elementary particles; the bubble chamber enabled him to observe the lifetimes of the particles. Starting in 1962, Glaser changed his field of research to molecular biology, starting with a project on ultraviolet-induced cancer. In 1964, he was given the additional title of Professor of Molecular Biology. Glaser's position was Professor of Neurobiology in the Graduate School.
Donald Glaser was born on September 21, 1926, in Cleveland, Ohio, to Russian Jewish immigrants and William J. Glaser, a businessman, he enjoyed music and played the piano and viola. He went to Cleveland Heights High School, where he became interested in physics as a means to understand the physical world, he died in his sleep at the age of 86 on February 2013 in Berkeley, California. He is survived by his wife, Lynn Glaser, his daughter, Louise Glaser, his son, William Glaser, his grandson Aaron Cohen, granddaughters Emily and Katherine Schreiner and Caroline and Julia Glaser. Glaser attended Case School of Applied Science, where he completed his bachelor's degree in physics and mathematics in 1946. During the course of his education there, he became interested in particle physics, he played viola in the Cleveland Philharmonic while at Case, taught mathematics classes at the college after graduation. He continued on to the California Institute of Technology, where he pursued his Ph. D. in physics.
His interest in particle physics led him to work with Nobel laureate Carl David Anderson, studying cosmic rays with cloud chambers. He preferred the accessibility of cosmic ray research over that of nuclear physics. While at Caltech he learned to design and build the equipment he needed for his experiments, this skill would prove to be useful throughout his career, he attended molecular genetics seminars led by Nobel laureate Max Delbrück. Glaser completed his doctoral thesis, The Momentum Distribution of Charged Cosmic Ray Particles Near Sea Level, after starting as an instructor at the University of Michigan in 1949, he received his Ph. D. from Caltech in 1950, he was promoted to Professor at Michigan in 1957. While teaching at Michigan, Glaser began to work on experiments that led to the creation of the bubble chamber, his experience with cloud chambers at Caltech had shown him that they were inadequate for studying elementary particles. In a cloud chamber, particles pass through gas and collide with metal plates that obscure the scientists' view of the event.
The cloud chamber needs time to reset between recording events and cannot keep up with accelerators' rate of particle production. He experimented with using superheated liquid in a glass chamber. Charged particles would leave a track of bubbles as they passed through the liquid, their tracks could be photographed, he created the first bubble chamber with ether. He experimented with hydrogen while visiting the University of Chicago, showing that hydrogen would work in the chamber, it has been claimed that Glaser was inspired to his invention by the bubbles in a glass of beer. His new invention was ideal for use with high-energy accelerators, so Glaser traveled to Brookhaven National Laboratory with some students to study elementary particles using the accelerator there; the images that he created with his bubble chamber brought recognition of the importance of his device, he was able to get funding to continue experimenting with larger chambers. Glaser was recruited by Nobel laureate Luis Alvarez, working on a hydrogen bubble chamber at the University of California at Berkeley.
Glaser accepted an offer to become a Professor of Physics there in 1959. Glaser was awarded the 1960 Nobel Prize for Physics for the invention of the bubble chamber, his invention allowed scientists to observe what happens to high-energy beams from an accelerator, thus paving the way for many important discoveries. After winning the Nobel Prize, Glaser began to think about switching from physics into a new field, he wanted to concentrate on science, found that as the experiments and equipment grew larger in scale and cost, he was doing more administrative work. He anticipated that the ever-more-complex equipment would cause consolidation into fewer sites and would require more travel for physicists working in high-energy physics. Recalling his interest in molecular genetics that began at Caltech, Glaser began to study biology, he attended biology seminars there. He spent a semester in Copenhagen with Ole Maaloe, the prominent Danish molecular biologist, he worked in UC Berkeley's Virus Lab, doing experiments with bacterial phages and mammalian cells.
He studied the development of cancer cells, in particular the skin cancer xeroderma pigmentosum. As with the bubble chamber
Georges Charpak was a Polish-born French physicist from a Jewish family, awarded the Nobel Prize in Physics in 1992. Georges Charpak was born Jerzy Charpak to Jewish parents and Maurice Charpak, in the village of Dąbrowica in Poland. Charpak's family moved from Poland to Paris when he was seven years old, beginning his study of mathematics in 1941 at the Lycée Saint Louis; the actor and film director André Charpak was his brother. During World War II Charpak served in the resistance and was imprisoned by Vichy authorities in 1943. In 1944 he was deported to the Nazi concentration camp at Dachau, where he remained until the camp was liberated in 1945. After classes préparatoires studies at Lycée Saint-Louis in Paris and at Lycée Joffre in Montpellier, he joined in 1945 the Paris-based École des Mines, one of the most prestigious engineering schools in France; the following year he became a naturalized French citizen. He graduated in 1948, earning the French degree of Civil Engineer of Mines becoming a pupil in the laboratory of Frédéric Joliot-Curie at the Collège de France during 1949, the year after Curie had directed construction of the first atomic pile within France.
While at the Collège, Charpak secured a research position for the National Centre for Scientific Research. He received his PhD in 1954 from Nuclear Physics at the Collège de France, receiving the qualification after having written a thesis on the subject of low radiation due to disintegration of nuclei. In 1959, he joined the staff of CERN in Geneva, where he invented and developed the multiwire proportional chamber; the chamber was patented and that superseded the old bubble chambers, allowing for better data processing. This new creation had been made public during 1968. Charpak was to become a joint inventor with Nlolc and Policarpo of the scintillation drift chamber during the latter parts of the 1970s, he retired from CERN in 1991. In 1980, Georges Charpak became professor-in-residence at École supérieure de physique et de chimie industrielles in Paris and held the Joliot-Curie Chair there in 1984; this is where he developed and demonstrated the powerful applications of the particle detectors he invented, most notably for enabling better health diagnostics.
He was the co-founder of a number of start-up in the biolab arena, including Molecular Engines Laboratories, Biospace Instruments and SuperSonic Imagine – together with Mathias Fink. He was elected to the French Academy of Sciences on 20 May 1985. Georges Charpak was awarded the Nobel Prize in Physics in 1992 "for his invention and development of particle detectors, in particular the multiwire proportional chamber", with affiliations to both École supérieure de physique et de chimie industrielles and CERN; this was the last time a single person was awarded the physics prize, as of 2017. In France, Charpak was a strong advocate for nuclear power. Charpak was a member of the Board of Sponsors of the Bulletin of the Atomic Scientists. Charpak married Dominique Vidal in 1953, they had three children. La vie à fil tendu, co-authored with Dominique Saudinos Devenez sorciers, devenez savants, co-authored with Henri Broch. Published in English as "Debunked!" by the Johns Hopkins University Press. Charpak, G. & M. Gourdin.
"The Kanti K System", European Organization for Nuclear Research, Paris University. Charpak, G. "Evolution of Some Particle Detectors Based On the Discharge in Gases", European Organization for Nuclear Research. Charpak, G. & F. Sauli, "High Accuracy, Two-Dimensional Read-Out in Multiwire Proportional Chambers", European Organization for Nuclear Research. Charpak, G.. Crittenden, J. A.. B.. D. M.. R.. N.. "Inclusive hadronic production cross sections measured in proton-nucleus collisions at. Sqrt. S = 27. 4 GeV". Physical Review D. 34: 2584. Bibcode:1986PhRvD..34.2584C. doi:10.1103/PhysRevD.34.2584. OSTI 7244218. Information from Official Nobel site Georges Charpak Georges Charpak U. S. Patents Georges Charpak on INSPIRE-HEP Georges Charpak, Nobel Luminaries Project, The Museum of the Jewish People at Beit Hatfutsot
Edwin Mattison McMillan was an American physicist and Nobel laureate credited with being the first-ever to produce a transuranium element, neptunium. For this, he shared the Nobel Prize in Chemistry with Glenn Seaborg in 1951. A graduate of California Institute of Technology, he earned his doctorate from Princeton University in 1933, joined the Berkeley Radiation Laboratory, where he discovered oxygen-15 and beryllium-10. During World War II, he worked on microwave radar at the MIT Radiation Laboratory, on sonar at the Navy Radio and Sound Laboratory. In 1942 he joined the Manhattan Project, the wartime effort to create atomic bombs, helped establish the project's Los Alamos Laboratory where the bombs were designed, he led teams working on the gun-type nuclear weapon design, participated in the development of the implosion-type nuclear weapon. McMillan co-invented the synchrotron with Vladimir Veksler, he returned to the Radiation Laboratory after the war, built them. In 1954 he was appointed associate director of the Radiation Laboratory, being promoted to deputy director in 1958.
On the death of Lawrence that year, he became director, he stayed in that position until his retirement in 1973. McMillan was born in Redondo Beach, California, on September 18, 1907, the son of Edwin Harbaugh McMillan and his wife Anna Marie McMillan née Mattison, he had Catherine Helen. His father was a physician, as was his father's twin brother, three of his mother's brothers. On October 18, 1908, the family moved to Pasadena, where he attended McKinley Elementary School from 1913 to 1918, Grant School from 1918 to 1920, Pasadena High School, from which he graduated in 1924. California Institute of Technology was only a mile from his home, he attended some of the public lectures there, he entered Caltech in 1924. He did a research project with Linus Pauling as an undergraduate and received his Bachelor of Science degree in 1928 and his Master of Science degree in 1929, writing an unpublished thesis on "An improved method for the determination of the radium content of rocks", he took his Doctor of Philosophy from Princeton University in 1933, writing his thesis on the "Deflection of a Beam of HCI Molecules in a Non-Homogeneous Electric Field" under the supervision of Edward Condon.
In 1932, McMillan was awarded a National Research Council fellowship, allowing him to attend a university of his choice for postdoctoral study. With his PhD complete, although it was not formally accepted until January 12, 1933, he accepted an offer from Ernest Lawrence at the University of California, Berkeley, to join the Berkeley Radiation Laboratory, which Lawrence had founded the year before. McMillan's initial work there involved attempting to measure the magnetic moment of the proton, but Otto Stern and Immanuel Estermann were able to carry out these measurements first; the main focus of the Radiation laboratory at this time was the development of the cyclotron, McMillan, appointed to the faculty at Berkeley as an instructor in 1935, soon became involved in the effort. His skill with instrumentation came to the fore, he contributed improvements to the cyclotron. In particular, he helped develop the process of "shimming", adjusting the cyclotron to produce a homogeneous magnetic field.
Working with M. Stanley Livingston, he discovered oxygen-15, an isotope of oxygen that emits positrons. To produce it, they bombarded nitrogen gas with deuterons; this was mixed with hydrogen and oxygen to produce water, collected with hygroscopic calcium chloride. Radioactivity was found proving that it was in the oxygen; this was followed by an investigation of the absorption of gamma rays produced by bombarding fluorine with protons. In 1935, McMillan and Robert Thornton carried out cyclotron experiments with deuteron beams that produced a series of unexpected results. Deuterons fused with a target nuclei, transmuting the target to a heavier isotope while ejecting a proton, their experiments indicated a nuclear interaction at lower energies than would be expected from a simple calculation of the Coulomb barrier between a deuteron and a target nucleus. Berkeley theoretical physicist Robert Oppenheimer and his graduate student Melba Phillips developed the Oppenheimer–Phillips process to explain the phenomenon.
McMillan became an assistant professor in 1936, an associate professor in 1941. With Samuel Ruben, he discovered the isotope beryllium-10 in 1940; this was both interesting and difficult to isolate due to its extraordinarily long half-life, about 1.39 million years. Following the discovery of nuclear fission in uranium by Otto Hahn and Fritz Strassmann in 1939, McMillan began experimenting with uranium, he bombarded it with neutrons produced in the Radiation Laboratory's 37-inch cyclotron through bombarding beryllium with deuterons. In addition to the nuclear fission products reported by Hahn and Strassmann, they detected two unusual radioactive isotopes, one with a half-life of about 2.3 days, the other with one of around 23 minutes. McMillan identified the short-lived isotope as uranium-239, reported by Hahn and Strassmann. McMillan suspected that the other was an isotope of a new, undiscovered element, with an atomic number of 93. At the time it was believed that element 93 would have similar chemistry to rhenium, so he began working with Emilio Segrè, an expert on that element from his discovery of its homolog technetium.
Both scientists began their work using the prevailing theory, but Segrè determined that McMillan's sample was not at all similar to rhenium. Instead, when he reacted it with hydrogen fluoride with a strong oxidizing agent present, it behaved like members of the rare-earth eleme