Louis Alexander Slotin (December 1, 1910 - May 30, 1946) is a Canadian physicist and chemist working at the Manhattan Project. During World War II, Slotin conducted research at Los Alamos National Laboratory. He conducted experiments with uranium and plutonium nuclei to determine the value of his critical mass. On May 21, 1946, Slotin staged a demonstration when he accidentally initiated a fission reaction, which released a loud radiation explosion. He received a lethal dose of radiation and died of acute radiation syndrome nine days later. Slotin is the second person to die of a critical accident, after the death of Harry Daghlian, who is exposed to radiation by the same core that kills Slotin. Slotin is openly hailed as a hero by the United States government for reacting quickly and preventing his accident killing co-workers. He was later criticized for failing to follow the protocol during the experiment.
Others are injured and their deaths several years later may result from exposure to their radiation. With the end of World War II, work to build additional nuclear devices was less urgent, and the accident ceased to work temporarily until an improved safety protocol was implemented at Los Alamos. The incidents and consequences have been dramatized in some fiction and non-fiction accounts.
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Slotin was the first child of three children born to Israel and Sonia Slotin, a Yiddish-speaking refugee who fled Russian pogroms to Winnipeg, Manitoba. He grew up in Winnipeg's North End neighborhood, a region with a large concentration of Eastern European immigrants. From the early days of Machray Primary School through his teenage years at St. John, Slotin is academically outstanding. His younger brother, Sam, later said that his brother "has an extreme intensity that allows him to study for hours."
At the age of 16, Slotin entered the University of Manitoba to pursue a degree in science. During his bachelor years, he received the University's Gold Medal in physics and chemistry. Slotin accepts B.Sc. degree in geology from the university in 1932 and M.Sc. Degree in 1933. With the help of one of his mentors, he won a scholarship to study at King's College London under the auspices of Arthur John Allmand, chair of the chemistry department, specializing in applied electrochemistry and photochemistry.
King's College King's College
While at King's College, Slotin differentiates himself as an amateur boxer by winning the college amateur bantam boxing championship. Later, he gave the impression that he had fought for the Spanish Republic and was trained to fly a fighter with the Royal Air Force. Author Robert Jungk recounts in his book More brilliant than a Thousand Sun: The Personal History of Atomic Scientists , the first report published on the Manhattan Project, that Slotin "has volunteered to serve in the Spanish Civil War, more for the sake of the tremor than for political reasons, he is often in extreme danger as an anti-aircraft gun. "During an interview several years later, Sam declared that his brother had" gone on a walking tour in Spain ", and he" did not participate in the war ". Slotin holds a Ph.D. degree in physical chemistry from the university in 1936. He won a prize for his thesis entitled "Investigation into Medium Molecular Formation Unstable During Some Chemical Reactions." After that, he spent six months working as a special investigator for Great Southern Railways Dublin, testing the nickel-zinc Drumm rechargeable battery used on the Dublin-Bray channel.
Maps Louis Slotin
Careers
University of Chicago
In 1937, after he failed to apply for a job at the National Research Council of Canada, the University of Chicago accepted him as a research associate. There, Slotin gained his first experience with nuclear chemistry, helping to build the first cyclotron in the western United States. The work was paid poorly and Slotin's father had to support him for two years. From 1939 to 1940, Slotin collaborated with Earl Evans, head of the university's biochemistry department, to produce radiocarbon (carbon-14 and carbon-11) from the cyclotron. While working together, the two men also used carbon-11 to show that plant cells have the capacity to use carbon dioxide for carbohydrate synthesis, through carbon fixation.
Slotin may have been present at the beginning of Enrico Fermi's "Chicago Pile-1", the first nuclear reactor, on December 2, 1942; event account does not agree on this point. So far, Slotin has also contributed to several papers in the field of radiobiology. His expertise on this issue attracted the attention of the United States government, and as a result he was invited to join the Manhattan Project, the United States' efforts to develop a nuclear bomb. Slotin works on the production of plutonium under future Nobel laureate Eugene Wigner at the university and later at Oak Ridge National Laboratory in Oak Ridge, Tennessee. He moved to Los Alamos National Laboratory in New Mexico in December 1944 to work in the group of bomb physics Robert Bacher.
Working at Los Alamos
At Los Alamos, the Slotin task consists of dangerous criticism testing, first with uranium in Otto Robert Frisch's experiments, and then with a plutonium core. Criticality testing involves bringing the mass of fissile material to a critical level to determine the value of its critical mass. Scientists call this flirting with the possibility of nuclear chain reactions as "tickling the tail of a dragon", based on statements by physicist Richard Feynman, who compared experiments to "tickle the sleeping dragon's tail". On July 16, 1945, Slotin collected the core for Trinity, the first atomic device to be detonated, and known as the "chief weapon of the United States" for his expertise in assembling nuclear weapons. Slotin received two round pins and a small circular silver for his work on the project.
In the winter of 1945-1946, Slotin surprised some of his colleagues with bold action. He repaired a six foot underwater instrument inside Pile Clinton while in operation, rather than waiting an extra day for the reactor to close. He does not wear his dosimetry badge, but his dose is estimated at least 100 roentgen. A dose of 1 Gy (~ 100 roentgen) can cause nausea and vomiting in 10% of cases, but generally can persist. Harry Daghlian's death Death of Harry Daghlian
On August 21, 1945, laboratory assistant Harry Daghlian, one of Slotin's close associates, conducted a critical mass experiment when he accidentally dropped a heavy tungsten carbide brick into a 6.2 kilogram (14 tons) plutonium-gallium alloy core. 24-year-old Daghlian is irradiated with large doses of neutron radiation. Subsequent estimates will show that this dose may not be fatal on its own, but it then receives additional delayed gamma radiation and burns the beta while unpacking its experiments. He quickly collapsed with acute radiation poisoning and died 25 days later at the Los Alamos hospital.
Planned back to teaching
After the war, Slotin expressed disdain for his personal involvement in the project. He commented, "I have been involved in a Navy test, it is very disgusting." Unfortunately for Slotin, his participation in Los Alamos is still needed because, as he says, "I am one of the few people left here who are experienced as bomb-makers." He is looking forward to continuing his teaching and research into biophysics and radiobiology at the University of Chicago. He started training substitutes, Alvin C. Graves, to take over his Los Alamos job.
Crash criticism
On May 21, 1946, with seven colleagues observing, Slotin conducted an experiment involving the manufacture of one of the first steps of a fission reaction by placing two half-balls of beryllium (a neutron reflector) around a 3.5-inch diameter (89 Â °). mm) core of plutonium. The experiment used a 6.2 kilogram plutonium core that had shone on Harry Daghlian, who was later called "demon core" for his role in two accidents. Slotin holds the top 228.6 mm (9 inches) beryllium section with his left hand through the thumb hole at the top while he maintains the half-split sphere using a screwdriver blade with his right hand, after removing the normally used shims. Using a screwdriver is not a normal part of the experimental protocol.
At 3:20, the screwdriver slips and the upper half of the beryllium falls, causing a "critical quick" reaction and a loud radiation explosion. At that time, the scientists in the room observed the blue light from ionizing the air and feeling the heat wave. Slotin had a sour taste in his mouth and an intense burning sensation in his left hand. He jerked his left hand up, lifted the upper half of the beryllium and dropped it to the floor, ending the reaction. However, he has been exposed to a lethal dose of neutron radiation. At the time of the accident, the dosimetry badge was inside a locked box about 100 feet (30 m) from the accident. Realizing that no one was in the room putting up their film badges, "immediately after the accident, Dr. Slotin requested that the badge be taken from the main box and placed on an important assembly". This strange response is associated with "vertigo" and there is no value to determine the actual dose received by the man in the room.
Others in the room at the time included Raemer E. Schreiber, Alvin Cushman Graves, Stanley Allan Kline, Marion Edward Cieslicki, Dwight Smith Young, Theodore P. Perlman, and Warrior. Patrick J. Cleary.
As soon as Slotin leaves the building, he vomits, a general reaction of exposure to intense ionizing radiation. Slotin colleagues immediately took him to the hospital, but radiation damage can not be changed.
On May 25, 1946, four of the eight men exposed during the incident had been discharged from the hospital. The Army doctor in charge of the hospital, Captain Paul Hageman, said that the immediate conditions of Slotin, Graves, Kline, and Young were satisfactory.
Slotin's Death
Despite intensive medical treatments and offers from various volunteers to donate blood for transfusion, Slotin's condition deteriorated rapidly. Slotin called his parents and they were flown at an Army cost from Winnipeg to be with their son. They arrived on the fourth day after the incident, and on the fifth day, Slotin's condition began to deteriorate rapidly.
Over the next nine days, Slotin suffers from "a set of radiation-induced trauma", including severe diarrhea, decreased urine output, swollen hands, erythema, "large blisters on the hands and forearms", intestinal paralysis, and gangrene. He has internal radiation burns all over his body, which a medical expert described as "three-dimensional sunlight". On the seventh day, he experienced periods of "mental confusion." His lips turned blue and he was put into an oxygen tent. He eventually experienced a "total disintegration of body functions" and went into a coma. Slotin died at 11 am on the morning of May 30, in the presence of his parents. He was buried at Shaarey Zedek Cemetery, Winnipeg, on June 2, 1946.
Other injuries and deaths
Graves, Kline and Young remain hospitalized after the death of Slotin. Graves, who stands closest to Slotin, also suffered from acute radiation and was hospitalized for several weeks. He survived, though he lived with neurological problems and chronic vision. Young also suffers from acute radiation syndrome, but recovers. On January 28, 1948 Graves, Kline and Perlman sought compensation for damages suffered during the incident. Graves completed his claim of $ 3,500.
Three of the observers eventually died of conditions known to be promoted by radiation: Graves of heart attack 20 years later at age 55; Cieslicki acute myeloid leukemia 19 years later at age 42; and Young from aplastic anemia and bacterial infection of the heart line 27 years later at age 83. Although some of these deaths may be the latent stochastic (random) effects of accidents, it is not possible to draw any definite conclusions from such small samples. set.
Core sharing
The involved core is intended for use in blasting Able, during the Crossroads series of nuclear weapons trials. The Slotin experiment is said to be the last performed before core detonation and is intended to be the final demonstration of its ability to be critical. After a critical accident it takes time to cool down. It was therefore rescheduled for the third test of the series, temporarily named Charlie , but this was canceled due to unexpected levels of radioactivity after the Baker underwater test and the inability to decontaminate the target warships. It is then melted and reused at the core then.
Radiation dose
The radiation dose received in these two accidents is unknown with any accuracy. Most doses are due to neutron radiation, which can not be measured with dosimetry equipment that day. Available equipment, film badges, not worn by personnel during accidents, and badges that should be planted under the table in the event of a disaster like this are not found. Disaster badge hanging on the wall does provide some useful data about gamma radiation.
The "tentative" estimates of the involved dose were made in 1948, based on dozens of assumptions, some of which are now known to be extremely untrue. In the absence of a personal dosimetry badge, study authors rely on measuring the activation of sodium in blood samples and urine victims as their primary data source. This activation will be caused by neutron radiation, but they convert all doses to equivalent doses of gamma or X-ray radiation. They conclude that Daghlian and Slotin may receive doses equivalent to 290 and 880 brakes (respectively) of gamma rays. The minimum and maximum estimates vary from about 50% to 200% of these values. The authors also calculated the doses equivalent to X-ray mixtures and soft gamma rays, which they believed gave a more realistic picture of exposure than equivalent gamma. In this model the equivalent X-ray dose is much higher, but will be concentrated in the network facing the source, while the gamma component penetrates the entire body. The equivalent dose of Slotin is estimated at 1930 R (roentgen) X-ray with 114Ã, R gamma, while the Daghlian equivalent dose is estimated at 480 R X ray with 110Ã, R gamma. Five hundred brakes are usually a lethal dose for humans.
In modern times dosimetry is done very differently. The equivalent dose will not be reported in roentgen; they will be calculated by different weighting factors, and they are not considered relevant to acute radiation syndrome as the absorbed dose. Recent documents have made various interpretations of the Slotin dose, ranging from 287 to 21 sievert. Based on excerpts and supporting reasons, the most reliable estimate is the Los Alamos memo of 1978 suggesting 10 Gy (n) 1.14 Gy (?) For Slotin and 2 Gy (n) 1.1 Gy (?) For Daghlian. This dose is consistent with the symptoms they experience.
Legacy
After the accident, Los Alamos ended all important assembly work. Future criticism testing of the fissile core is performed with remotely controlled machines, such as the "Godiva" series, with operators at a safe distance to prevent hazards in the event of an accident.
Pada 14 Juni 1946, associate editor dari Los Alamos Times , Thomas P. Ashlock, menulis sebuah puisi berjudul "Slotin - A Tribute":
The official story released at the time was that Slotin, quickly removing the top hemisphere, was a hero to end the critical reaction and shield seven other observers indoors: "Dr. Slotin's immediate reaction to the immediate risk of his own life was prevented. from experiments that will of course result in the deaths of seven people working with him, as well as serious injuries to others around the public. "The interpretation of this event was passed at that time by Alvin Graves, who stood closest to Slotin when the accident occurred. Graves, such as Slotin, had previously shown a low concern for nuclear safety, and would later allege that the risk of the fall "was created in the minds of weak lawmakers." Another witness to the accident, Raemer E. Schreiber, spoke publicly decades later, arguing that Slotin used improper and insecure procedures, endangering others in the lab with himself. Robert B. Brode has reported a rumor to that effect in 1946.
The event was told in the 1955 novel Dexter Masters The Accident , a fictional story of the last few days of the life of a nuclear scientist who suffered radiation poisoning. The portrayal of critical incidents includes the 1989 film Fat Man and Little Boy, in which John Cusack plays a fictional character named Michael Merriman based on Slotin, and Louis Slotin Sonata , a drama outside Broadway in 2001 directed by David P. Moore.
In 1948, Slotin colleagues at Los Alamos and the University of Chicago initiated the Louis A. Slotin Memorial Fund for the lectures on physics given by eminent scientists such as Robert Oppenheimer and Nobel laureates Luis Walter Alvarez and Hans Bethe. The warning fund lasted until 1962. In 2002, an asteroid discovered in 1995 was named 12423 Slotin in his honor.
Unit dollar reactivity
According to Weinberg and Wigner, Slotin was the first to propose the name of the dollar for a reactivity interval between delayed and rapidly delayed criticisms; 0 is a stand-alone chain reaction point, a dollar is the point at which neutrons are released slowly, no longer needed to support chain reactions, and enter a domain called "super-" critical. The stable nuclear reactor operates between 0 and one dollar; travel and nuclear explosives operate on a dollar. The hundredth part of a dollar is called a cent (reactivity). When talking about a really fast critical event, some users call the sen "too critical" as a relative unit.
Note
References
External links
- Louis P. Slotin - The Heritage Conservation Association of the Manhattan Project
- Louis Slotin, profile - GCS Research Research
- The Secret Life of Louis Slotin - The Canadian Nuclear Society
- Louis Slotin in Discover Mausoleum
Source of the article : Wikipedia
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