Semion Braude
Encyclopedia
Semion Yakovlevich Braude was a Ukrainian physicist and radio astronomer.
Of Ashkenazi Jewish descent, Buaude was born in Poltava
, Ukraine
, and pursued his higher education at the Kharkov University (KU), receiving his undergraduate degree from the Physics and Mathematics Department in 1932. He then joined the staff of ths Laboratory of Electromagnetic Oscillations (LEMO) at the Ukrainian Physico-Technical Institute (UPTI), and also began graduate work at KU. His mentor was Abram A. Slutskin
, professor at KU as well as head of the LEMO.
Much of the activities of the LEMO involved the development of magnetrons for generating ultra-high frequency (UHF) signals. In 1936, the LEMO was tasked to study the application of magnetrons in a pulsed radio-location (radar) system for use by anti-aircraft batteries. For this project, Braude designed a superheterodyne receiver
, using a low-power, tunable magnetron for use as the local oscillator. He also completed the Kandidat Nauk (Candidate of Science – approximatelt equivalent to a Ph.D. degree) in 1937.
The radio-location system, code-named Zenit (a popular football team at that time), was first tested in 1938, detecting an aircraft at a distance of 3 km. After improvements were made, the revised system was tested in 1940, providing range, altitude, and azimuth for a target aircraft at up to 25 km distance. Although the time required to make the measurements was too great for anti-aircraft applications, the Zenit was the first three-coordinate radio-location system developed in the Soviet Union.
The German invasion of the Soviet Union started in June 1941, and all of the UPTI was evacuated to the Far East. The LEMO, including Slutskin, went to Bukhar in Uzbekistan
. There Braude continued work on radio-location equipment, particularly the Rubin, a further improvement of the Zenit. He also continued his studies under Slutskin, being awarded the higher D.Sc. degree in 1943. He was given the title of Professor
in 1944. The preliminary testing of Rubin turned up a previously unreported phenomena in radio-signal propagation, later called surface or atmospheric duct
ing, resulting in a major decrease in signal attenuation; Braude initiated studies in this area.
Following the war, the LEMO returned to Kharkov in mid-1945, remaining independent of the UPTI.. There Braude continued research in large-scale radio propagation, eventually turning his full interest to interferometry
and radio-signal analysis. In 1955, the LEMO became the Institute of Radiophysics and Electronics (IRE) of the National Academy of Sciences of Ukraine (NASU); Braude played a major role in forming the IRE. He was made a Vice-Director of the IRE, heading the Radio Astronomy Department and pioneering decametre
-wavelength radio astronomy in Ukraine. In 1985, he was instrumental in forming a new academic establishment, the Institute of Radio Astronomy of NASU, branched off IRE on the basis of the former Radio Astronomy Department.
Braude’s research at the IRE centered on developing large-scale radio interferometers for precisely examining extraterrestrial radio sources. He headed a program that created the Ukrainian T-shaped Radio telescope, second modification
. This was the world's largest radio telescope
at decametre
wavelengths, with a resolution on the order of an arcsecond
and a sensitivity of about 10 Jy (jansky
).
Braude was a member of the editorial board of the Radiophysics and Quantum Electronics journal since it was founded in 1958. During his lifetime, he published 5 nomographs and over 300 scientific papers, and mentored some 35 doctoral students. He remained professionally active until his death in 2003.
Of Ashkenazi Jewish descent, Buaude was born in Poltava
Poltava
Poltava is a city in located on the Vorskla River in central Ukraine. It is the administrative center of the Poltava Oblast , as well as the surrounding Poltava Raion of the oblast. Poltava's estimated population is 298,652 ....
, Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
, and pursued his higher education at the Kharkov University (KU), receiving his undergraduate degree from the Physics and Mathematics Department in 1932. He then joined the staff of ths Laboratory of Electromagnetic Oscillations (LEMO) at the Ukrainian Physico-Technical Institute (UPTI), and also began graduate work at KU. His mentor was Abram A. Slutskin
Abram A. Slutskin
Abram A. Slutskin was a Russian scientist and professor who had a major role in shaping radio science in the Soviet Union. He was a pioneer in cavity magnetron development and the application of these devices in radio-location systems....
, professor at KU as well as head of the LEMO.
Much of the activities of the LEMO involved the development of magnetrons for generating ultra-high frequency (UHF) signals. In 1936, the LEMO was tasked to study the application of magnetrons in a pulsed radio-location (radar) system for use by anti-aircraft batteries. For this project, Braude designed a superheterodyne receiver
Superheterodyne receiver
In electronics, a superheterodyne receiver uses frequency mixing or heterodyning to convert a received signal to a fixed intermediate frequency, which can be more conveniently processed than the original radio carrier frequency...
, using a low-power, tunable magnetron for use as the local oscillator. He also completed the Kandidat Nauk (Candidate of Science – approximatelt equivalent to a Ph.D. degree) in 1937.
The radio-location system, code-named Zenit (a popular football team at that time), was first tested in 1938, detecting an aircraft at a distance of 3 km. After improvements were made, the revised system was tested in 1940, providing range, altitude, and azimuth for a target aircraft at up to 25 km distance. Although the time required to make the measurements was too great for anti-aircraft applications, the Zenit was the first three-coordinate radio-location system developed in the Soviet Union.
The German invasion of the Soviet Union started in June 1941, and all of the UPTI was evacuated to the Far East. The LEMO, including Slutskin, went to Bukhar in Uzbekistan
Uzbekistan
Uzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....
. There Braude continued work on radio-location equipment, particularly the Rubin, a further improvement of the Zenit. He also continued his studies under Slutskin, being awarded the higher D.Sc. degree in 1943. He was given the title of Professor
Professor
A professor is a scholarly teacher; the precise meaning of the term varies by country. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences; a teacher of high rank...
in 1944. The preliminary testing of Rubin turned up a previously unreported phenomena in radio-signal propagation, later called surface or atmospheric duct
Atmospheric duct
In telecommunication, an atmospheric duct is a horizontal layer in the lower atmosphere in which the vertical refractive index gradients are such that radio signals are guided or ducted, tend to follow the curvature of the Earth, and experience less attenuation in the ducts than they would if...
ing, resulting in a major decrease in signal attenuation; Braude initiated studies in this area.
Following the war, the LEMO returned to Kharkov in mid-1945, remaining independent of the UPTI.. There Braude continued research in large-scale radio propagation, eventually turning his full interest to interferometry
Interferometry
Interferometry refers to a family of techniques in which electromagnetic waves are superimposed in order to extract information about the waves. An instrument used to interfere waves is called an interferometer. Interferometry is an important investigative technique in the fields of astronomy,...
and radio-signal analysis. In 1955, the LEMO became the Institute of Radiophysics and Electronics (IRE) of the National Academy of Sciences of Ukraine (NASU); Braude played a major role in forming the IRE. He was made a Vice-Director of the IRE, heading the Radio Astronomy Department and pioneering decametre
Decametre
A decametre or dekametre is a very rarely used unit of length in the metric system, equal to ten metres, the SI base unit of length. It can be written in scientific notation as , meaning .This measure is included mostly for completeness...
-wavelength radio astronomy in Ukraine. In 1985, he was instrumental in forming a new academic establishment, the Institute of Radio Astronomy of NASU, branched off IRE on the basis of the former Radio Astronomy Department.
Braude’s research at the IRE centered on developing large-scale radio interferometers for precisely examining extraterrestrial radio sources. He headed a program that created the Ukrainian T-shaped Radio telescope, second modification
Ukrainian T-shaped Radio telescope, second modification
The Ukrainian T-shaped Radio telescope, second modification is the world's largest radio telescope at decametre wavelengths. It was built in the early 1970s near the village of Grakovo , 65 km south-east from Kharkov, Soviet Union...
. This was the world's largest radio telescope
Radio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...
at decametre
Decametre
A decametre or dekametre is a very rarely used unit of length in the metric system, equal to ten metres, the SI base unit of length. It can be written in scientific notation as , meaning .This measure is included mostly for completeness...
wavelengths, with a resolution on the order of an arcsecond
Minute of arc
A minute of arc, arcminute, or minute of angle , is a unit of angular measurement equal to one sixtieth of one degree. In turn, a second of arc or arcsecond is one sixtieth of one minute of arc....
and a sensitivity of about 10 Jy (jansky
Jansky
The flux unit or jansky is a non-SI unit of spectral flux density equivalent to 10−26 watts per square metre per hertz...
).
Braude was a member of the editorial board of the Radiophysics and Quantum Electronics journal since it was founded in 1958. During his lifetime, he published 5 nomographs and over 300 scientific papers, and mentored some 35 doctoral students. He remained professionally active until his death in 2003.
Awards and honors
- State Prize of the Soviet Union for science and engineering, 1952.
- State Prize of the Ukraine for science and engineering, 1977.
- A. S. Popov Golden Medal by the USSR Academy of Sciences, 1983.
- Prize and Medal of the Euro-Asian Astronomical Society, 1997.
- On April 17, 2009, the International Astronomical UnionInternational Astronomical UnionThe International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...
named the Braude crater on the MoonMoonThe Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
after him.