X-ray

Japanese: レントゲン

German physicist. He entered the mechanical engineering department of the ETH Zurich in 1865, where he studied under RJE Clausius and others. He qualified as a mechanical engineer in 1868, and received his doctorate from the University of Zurich the following year, becoming an assistant in experimental physics under AA Kundt. Kundt's guidance and support greatly influenced his development. In 1879 he became a professor at the University of Giessen, and in 1888 he became a professor at the University of Würzburg, later becoming its rector. At the University of Giessen, he discovered the Kerr effect of electric fields on optical phenomena at almost the same time as J. Kerr. He also detected a magnetic field around a polarized dielectric body rotating at high speed, which provided the basis for HA Lorentz's theory of the electron. His method of making his own experimental equipment and his deep interest in electromagnetism led him to notice the exposure of a photographic plate near a cathode ray tube covered with a black cloth (which he initially thought was a longitudinal electromagnetic wave), and he discovered X-rays at the end of 1895. The discovery of X-rays led to advances in surgery and also prompted J. J. Thomson to identify the electron. For his discovery of X-rays, he was awarded the first Nobel Prize in Physics.

X-ray X-ray
roentgen

A unit of radiation exposure such as X-rays and gamma rays. It is usually expressed as R. The International System of Units (SI units) for expressing radiation exposure is C kg ^-1 , which is defined as "the exposure dose at which ionizing particles emitted per kg of air by exposure to X-rays or gamma rays produce groups of positive and negative ions, each with an electric charge of 1 C, in the air." Therefore, the relationship between roentgen R and C kg ^-1 is as follows:

1 R = 2.58×10 ⁻⁴ C kg ⁻¹

In the past, the roentgen was the standard unit, and it was defined as the dose that would produce positive and negative ions, each with a charge of 1 esu, in 0.001293 g of air (1 ^cm3 under standard conditions). The exposure dose rate of gamma rays from a point source of 1 Ci of ⁶⁰ Co is approximately 1.35 R h ^-1 at a distance of 1 m.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

Japanese:

ドイツの物理学者．1865年チューリヒ工科大学機械工学科に入学し，R.J.E. Clausius(クラウジウス)などに学ぶ．1868年機械工学技師の資格を取得，翌年チューリヒ大学から学位を取得して，A.A. Kundtの実験物理学助手となる．Kundtによる薫陶と援助がかれを大きく育てた．1879年ギーセン大学教授，1888年ビュルツブルク大学教授，のちに学長となる．ギーセン大学では，J. Kerrとほぼ同時に，光学現象に対する電場のカー効果を見いだした．また，高速で回転させた分極誘電体の周囲に磁場を検出して，H.A. Lorentzの電子論の基礎を与えた．実験器具を自作するかれの手法と，電磁気学への深い関心から黒い布で覆った陰極線管付近の写真乾板の感光に気づき(当初，縦波の電磁波だと考えた)，1895年末にX線を発見した．X線の発見は，外科手術の進歩をもたらし，またJ.J. Thomsonによる電子の同定を促した．X線の発見で，第一回ノーベル物理学賞を受賞した．

レントゲン
レントゲン
roentgen

X線やγ線のような電磁波性放射線の照射線量を表す単位．通常，R で表す．放射線の照射線量を表す国際単位系(SI単位)は C kg^－1 であり，“X線またはγ線の照射によって空気1 kg につき放出された電離性粒子が，空気中においてそれぞれ1 C の電気量を有する正および負のイオン群を生じさせる照射線量”と定義されているので，レントゲン R と C kg^－1 とは次の関係にある．

1 R ＝ 2.58×10^－4 C kg^－1

古くはレントゲンのほうが基準的な単位で，0.001293 g の空気(標準状態で1 cm³)中に，それぞれ1 esu の電荷をもつ正・負イオンをつくるような線量と定義されていた．1 Ciの ⁶⁰Co の点状線源からのγ線の照射線量率は，1 m 離れた点で約1.35 R h^－1 である．

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