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Brooks, Harriet

thorium rutherford mcgill radioactive

(1876–1933) Canadian nuclear physicist.

Harriet Brooks went to McGill University in Montreal and gained a first-class honours degree in 1898. She was invited to join well-equipped physics research group at McGill, as his first graduate student, and gained a master’s degree in 1901; the highest award at that time and the first awarded to a woman at McGill.

Radioactivity was then a very novel research area, the first radioactive effects having been observed by in 1896. Brooks studied the ‘radioactive substance’ given off by thorium and, using a diffusion method, she identified the emanation as a radioactive gas of relative atomic weight in the 40–100 range. The method gave a low value for the gas, which is an isotope of radon, but it was shown that the gas had a significantly lower molecular weight than thorium and so could not be simply a gaseous form of thorium. This led Rutherford and to the realization that a transmutation of one element to another had occurred; this entirely novel idea was central to the whole development of nuclear physics and chemistry.

Later Brooks worked on a comparison of the beta-radiations from the elements thorium, uranium, radium and polonium, and showed it to consist of fast negative particles. She spent 1902–03 working with at the Cavendish Laboratory in Cambridge and in a letter to Rutherford in 1903 refers to radioactivity decreasing to one-half of its value in about a minute, the first measurement of the half-life of the thorium emanation (radon-220).

Back at McGill Brooks observed the recoil of the radioactive polonium atom, although she attributed this phenomenon to volatility of the decay product from the polonium; Rutherford recounted Brooks’s findings in his Bakerian Lecture in 1904. Later, this important recoil effect was rediscovered by and others.

In 1904 Harriet Brooks moved to Barnard College, New York City as tutor in physics, and 2 years later became engaged to be married to a physicist from Columbia. The dean of the college insisted that Brooks must resign, saying ‘the good of the College and the dignity of the woman’s place in the home demand that your marriage shall be a resignation’. This was common practice at the time and Brooks debated the decision, but the result of the dispute led to her resignation and a broken engagement. She went to the Curie Institute (1906–07) and worked with André Debierne (1874–1949) on the recoil of radioactive atoms using the radium decay series. In 1907 she chose to marry and abandoned her career.

Rutherford said of her that ‘next to Mme she is the most pre-eminent woman physicist in the department of radioactivity’. If she had been allowed to combine research work and marriage her work might have been better appreciated. She died at the age of 56 of a ‘blood disorder’ and it is hard to avoid the suspicion that exposure to radiation was involved; in the ‘golden age’ of physics its hazards were not appreciated.

Brooks, Juanita Leavitt (1898–?) - Biography [next] [back] Brooks, Garth

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