Harry Boot

Last updated

Harry Boot
Born29 July 1917
Died8 February 1983 (aged 65)
Alma mater University of Birmingham
Known for cavity magnetron
Scientific career
Fields physics
Doctoral advisor Mark Oliphant

Henry Albert Howard "Harry" Boot (29 July 1917 – 8 February 1983) was an English physicist who with Sir John Randall and James Sayers developed the cavity magnetron, which was one of the keys to the Allied victory in the Second World War. [1]

Sir John Turton Randall, was an English physicist and biophysicist, credited with radical improvement of the cavity magnetron, an essential component of centimetric wavelength radar, which was one of the keys to the Allied victory in the Second World War. It is also the key component of microwave ovens.

Professor James Sayers was an important Northern Irish physicist, who played a crucial role in developing centimetric radar - now used in microwave ovens.

Cavity magnetron device for generating microwaves

The cavity magnetron is a high-powered vacuum tube that generates microwaves using the interaction of a stream of electrons with a magnetic field while moving past a series of open metal cavities. Electrons pass by the openings to these cavities and cause radio waves to oscillate within, similar to the way a whistle produces a tone when excited by an air stream blown past its opening. The frequency of the microwaves produced, the resonant frequency, is determined by the cavities' physical dimensions. Unlike other vacuum tubes such as a klystron or a traveling-wave tube (TWT), the magnetron cannot function as an amplifier in order to increase the intensity of an applied microwave signal; the magnetron serves solely as an oscillator, generating a microwave signal from direct current electricity supplied to the vacuum tube.


Poynting Physics Building, Birmingham University Poynting Physics building 2.jpg
Poynting Physics Building, Birmingham University
An original six-cavity magnetron. Original cavity magnetron, 1940 (9663811280).jpg
An original six-cavity magnetron.
University of Birmingham - Poynting Physics Building - blue plaque University of Birmingham - Poynting Physics Building - blue plaques group - Randall Boot.jpg
University of Birmingham – Poynting Physics Building – blue plaque

Henry Boot was born in Birmingham and attended King Edward's School, Birmingham and the University of Birmingham. [2] While working on his PhD the war broke out. His professor Mark Oliphant had seen the klystron at Stanford University but it produced insufficient power to be useful as a radar transmitter. He assigned John Randall and Boot to the problem. By late February 1940, they had invented the much more powerful cavity magnetron which was fitted in an experimental radar by May 1940. [2]

Birmingham City in the English Midlands, 2nd highest population of UK cities

Birmingham is the second-most populous city in the United Kingdom, after London, and the most populous city in the English Midlands. It is also the most populous metropolitan district in the United Kingdom, with an estimated 1,137,123 inhabitants, and is considered the social, cultural, financial, and commercial centre of the Midlands. It is the main local government of the West Midlands conurbation, which is the third most populated urban area in the United Kingdom, with a population of 2,897,303 in 2017. The wider Birmingham metropolitan area is the second largest in the United Kingdom with a population of over 4.3 million. It is frequently referred to as the United Kingdom's "second city".

King Edwards School, Birmingham independent day school for boys in Birmingham, England

King Edward's School (KES) is an independent day school for boys in Edgbaston, an area of Birmingham, England. Founded by King Edward VI in 1552, it is part of the Foundation of the Schools of King Edward VI in Birmingham.

University of Birmingham university in Birmingham, England, United Kingdom

The University of Birmingham is a public research university located in Edgbaston, Birmingham, United Kingdom. It received its royal charter in 1900 as a successor to Queen's College, Birmingham and Mason Science College, making it the first English civic or 'red brick' university to receive its own royal charter. It is a founding member of both the Russell Group of British research universities and the international network of research universities, Universitas 21.

James Sayers later refined the magnetron still further by strapping alternate cavities. [3] As with many British inventions of this period, the magnetron was provided to the US for free when they entered World War II. Initially Boot and Randall were awarded £50 each for the magnetron for "improving the safety of life at sea", but in 1949 Boot, Randall and Sayers received a £36,000 prize for their work.

World War II 1939–1945 global war

World War II, also known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries. The major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China. It included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, and the only use of nuclear weapons in war.

After a brief time at British Thomson-Houston, Rugby, in the latter years of the war, Boot returned to Birmingham as the Nuffield Research Fellow. After some work on nuclear physics, Boot returned to magnetrons and after the war built a cyclotron at Birmingham.

British Thomson-Houston company

British Thomson-Houston (BTH) was a British engineering and heavy industrial company, based at Rugby, Warwickshire, England and founded as a subsidiary of the General Electric Company (GE) of Schenectady, New York, USA. They were known primarily for their electrical systems and steam turbines. BTH was taken into British ownership and amalgamated with the similar Metropolitan-Vickers company in 1928 to form Associated Electrical Industries (AEI), but the two brand identities were maintained until 1960. The holding company, Associated Electrical Industries (AEI), later merged with GEC, the remnants of which exist today as Marconi Corporation.

Cyclotron a type of particle accelerator

A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in 1929-1930 at the University of California, Berkeley, 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 rapidly varying electric field. Lawrence was awarded the 1939 Nobel prize in physics for this invention.

In 1948 he joined the Scientific Civil Service, and was appointed Principal Scientific Officer (PSO) at Services Electronic Research Laboratories, in Baldock in Hertfordshire, where he undertook research on microwaves, magnetrons, plasma physics and lasers.

Baldock historic market town in Hertfordshire, England

Baldock is a historic market town in the local government district of North Hertfordshire in the ceremonial county of Hertfordshire, England where the River Ivel rises. It lies 33 miles (53 km) north of London, 15 miles (24 km) southeast of Bedford, and 14 miles (23 km) north northwest of the county town of Hertford. Nearby towns include Royston to the northeast, Letchworth and Hitchin to the southwest and Stevenage to the south.

Hertfordshire County of England

Hertfordshire is one of the home counties in England. It is bordered by Bedfordshire and Cambridgeshire to the north, Essex to the east, Greater London to the south, and Buckinghamshire to the west. For government statistical purposes, it is placed in the East of England region.

He enjoyed sailing, owning two boats at Salcombe in Devon. He frequently went down there to the family holiday home with his wife Penelope, and his two sons, Christopher and Nicholas.

Salcombe a town in South Hams, United Kindom

Salcombe is a popular resort town in the South Hams district of Devon, south west England. The town is close to the mouth of the Kingsbridge Estuary, mostly built on the steep west side of the estuary. It lies within the South Devon Area of Outstanding Natural Beauty (AONB). The town's extensive waterfront and the naturally sheltered harbour formed by the estuary gave rise to its success as a boat and shipbuilding and sailing port and, in modern times, tourism especially in the form of pleasure sailing and yachting. The town is also home to a traditional shellfish fishing industry. The town is part of the electoral ward of Salcombe and Malborough, for which the 2011 census recorded a total population of 3,353.

He retired in 1977 and died in Cambridge on 8 February 1983. [4]

Related Research Articles

Mark Oliphant 27th Governor of South Australia

Sir Marcus Laurence Elwin "Mark" Oliphant was an Australian physicist and humanitarian who played an important role in the first experimental demonstration of nuclear fusion and in the development of nuclear weapons.

John Cockcroft British physicist

Sir John Douglas Cockcroft, was a British physicist who shared with Ernest Walton the Nobel Prize in Physics in 1951 for splitting the atomic nucleus, and was instrumental in the development of nuclear power.

Sir Henry Thomas Tizard was an English chemist, inventor and Rector of Imperial College, who developed the modern "octane rating" used to classify petrol, helped develop radar in World War II, and led the first serious studies of UFOs.

History of radar aspect of history

The history of radar started with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects. This possibility was suggested in James Clerk Maxwell's seminal work on electromagnetism. However, it was not until the early 20th century that systems able to use these principles were becoming widely available, and it was German inventor Christian Hülsmeyer who first used them to build a simple ship detection device intended to help avoid collisions in fog. Numerous similar systems, which provided directional information to objects over short ranges, were developed over the next two decades.

The Tizard Mission, officially the British Technical and Scientific Mission, was a British delegation that visited the United States during the Second World War in order to obtain the industrial resources to exploit the military potential of the research and development (R&D) work completed by the UK up to the beginning of World War II, but that Britain itself could not exploit due to the immediate requirements of war-related production. It received its popular name from the program's instigator, Henry Tizard. Tizard was a British scientist and chairman of the Aeronautical Research Committee, which had propelled the development of radar.

Edward George "Taffy" Bowen, CBE, FRS was a Welsh physicist who made a major contribution to the development of radar, and so helped win both the Battle of Britain and the Battle of the Atlantic. He was also an early radio astronomer, playing a key role in the establishment of radioastronomy in Australia and the United States.

Albert W. Hull American inventor

Albert Wallace Hull is an American physicist and electrical engineer who made contributions to the development of vacuum tubes, and invented the magnetron. He was a member of the National Academy of Sciences.

GEC Hirst Research Centre was one of the first specialised industrial research laboratories to be built in Britain, and was part of the General Electric Company plc empire. It was demolished in the early 1990s primarily because GEC had stopped funding serious research, as it was not immediately profitable.

The Radiation Laboratory, commonly called the Rad Lab, was a microwave and radar research laboratory located at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts (US). It was first created in October 1940 and operated until 31 December 1945 when its functions were dispersed to industry, other departments within MIT, and in 1951, the newly formed MIT Lincoln Laboratory.

Albert Percival Rowe, CBE, often known as Jimmy Rowe or A. P. Rowe, was a radar pioneer and university vice-chancellor. A British physicist and senior research administrator, he played a major role in the development of radar before and during World War II.

Yoji Ito Japanese physicist

Yoji Ito was an engineer and scientist that had a major role in the Japanese development of magnetrons and the Radio Range Finder.

W. A. S. Butement Australian scientist

William Alan Stewart Butement was a defence scientist and public servant. A native of New Zealand, he made extensive contributions to radar development in Great Britain during World War II, served as the first chief scientist for the Australian Defence Scientific Service, then ended his professional career with a research position in private business.

Abram A. Slutskin (1881–1950) 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 (radar) systems.

John Tasker Henderson was a Canadian Physicist whose career was with the National Research Council (NRC). Educated at McGill and London, Henderson joined the NRC in 1933 where he worked on the effects of the ionosphere on radio signals and the Direction Finder invented by A.G.L. McNaughton and W.A. Steel.

John G. Trump American engineer and physicist

John George Trump was an American electrical engineer, inventor, and physicist. A professor at the Massachusetts Institute of Technology from 1936 to 1973, he was a recipient of U.S. President Ronald Reagan's National Medal of Science and a member of the National Academy of Engineering. John Trump was noted for developing rotational radiation therapy. Together with Robert J. Van de Graaff, he developed one of the first million-volt X-ray generators. He was the paternal uncle of Donald Trump, who would later go on to become the 45th president of the United States.

Eric Burhop Australian physicist and humanitarian

Eric Henry Stoneley Burhop, was an Australian physicist and humanitarian.


  1. "Briefcase 'that changed the world'". BBC. 20 October 2017.
  2. 1 2 "Archives Biographies: Henry Boot". The Institution of Engineering and Technology. Retrieved 26 November 2018.
  3. Early Centimetric Ground Radars – A Personal Reminiscence
  4. "Waymarking.com" . Retrieved 30 May 2012.