SU655895A1

SU655895A1 - X-ray thickness meter

Info

Publication number: SU655895A1
Application number: SU772542160A
Authority: SU
Inventors: Валерий Николаевич Яковлев
Original assignee: Предприятие П/Я Г-4807
Priority date: 1977-11-16
Filing date: 1977-11-16
Publication date: 1979-04-05

Description

Изобретение относитс к технике измерени толщины материалов с помощью ионизирующих излучений по его ослаблениЕО при изменении состава образца.The invention relates to a technique for measuring the thickness of materials with the help of ionizing radiation by attenuating it when the sample composition changes.

Известные устройства измерени толщины содержат несколько источников гаммаизлучений с разной энергией излучени 1The known thickness measurement devices contain several gamma radiation sources with different radiation energy 1

По степени ослаблени излучений с разной энергией подсчитывают отклонение состава образца от стандарта на основе рещени системы уравнений.According to the degree of attenuation of radiation with different energies, the deviation of the sample composition from the standard is calculated based on the solution of the system of equations.

Применение изотопных источников не позвол ет выбрать оптимальные энергии излучений из-за наличи спектра излучений, кроме того, изотопы имеют разные периоды полураспада , что преп тствует созданию совмещенного источника. Применение в качестве источников рентгеновских аппаратов усложн ет конструкцию устройства.The use of isotopic sources does not allow choosing the optimal radiation energies due to the presence of a spectrum of radiations; moreover, isotopes have different half-lives, which prevents the creation of a combined source. Using x-ray devices as sources complicates the design of the device.

Наиболее близким по технической сущности к данному изобретению вл етс рентгеновский толщиномер, содержащий рентгеновскую трубку с источником питани , устанавливаемые с одной стороны контролируемого образца, и детектор, располагаемый с другой стороны образца 2.The closest to the technical nature of this invention is an X-ray thickness gauge containing an X-ray tube with a power source, mounted on one side of the test sample, and a detector positioned on the other side of sample 2.

Описанный толщиномер имеет низкую точность учета изменени состава образца в случае многокомпонентного состава образца , так как дл полного учета необходимо более двух источников гамма-излучени с разной эффективной энергией.The thickness gauge described has a low accuracy in accounting for changes in the sample composition in the case of a multi-component sample composition, since more than two sources of gamma radiation with different effective energy are required to take full account.

Целью изобретени вл етс повышение точности измерени толщины образца при изменении его состава.The aim of the invention is to improve the accuracy of measuring the thickness of the sample when its composition changes.

Поставленна цель достигаетс тем, что источник питани выполнен импульсным, а толщиномер снабжен пороговым устройством , подключенным входом к выходу источника импульсного питани , регулируемыми элементами временной задержки, входы которых соединены с выходом порогового устройства , электронными ключами и импульсными измерител ми тока, подключенными входами к выходам электронных ключей, первые входы которых подсоединены к соответствующим выходам регулируемых элементов временной задержки, а вторые - к выходу детектора.The goal is achieved by the fact that the power source is pulsed, and the thickness gauge is equipped with a threshold device connected to the output of a pulsed power source, adjustable time delay elements whose inputs are connected to the output of the threshold device, electronic switches and pulsed current meters connected to the outputs electronic keys, the first inputs of which are connected to the corresponding outputs of the adjustable time delay elements, and the second - to the detector output.

Claims

The drawing shows a block diagram of the thickness gauge, calculated on three measurements of the detector signal during one period of X-ray emission. The thickness gauge contains a pulsed high-voltage power supply source 1, an X-ray tube 2, sample 3, a threshold circuit 4, time delay elements 5-7, electronic keys 8-10. The thickness gauge works as follows. The pulsed high-voltage power supply 1 provides a high-voltage power X-ray tube 2 that emits x-rays to sample 3. At the same time, the power supply outputs a reduced voltage to threshold circuit 4, which is triggered at the beginning of the X-ray tube emission period and outputs a pulse to all inputs connected to it elements 5-7 time delay. The delay time is set within the period of radiation for the moments at which the tube will have certain voltages, which means the radiation will be with a certain effective energy. At these moments, the delay lines open for the duration of the pulse the electronic switches 8–10, which pass the signal of the detector 11 to the corresponding pulse current meters 12–14, the signals of which are recorded by conventional current meters. As an X-ray tube supplied by a pulsating high-voltage, any x-ray apparatus made according to a half-wave circuit can be used; the Schmitt trigger is used as the threshold element, and the one-shot is used as the delay lines. The proposed thickness gauge favorably differs from the prototype, since it allows one to do with only one x-ray apparatus instead of two, which gives a great economic effect. In addition, the design of the thickness gauge is simplified, since it is not necessary to combine the radiation fluxes of two X-ray machines. In addition, the proposed thickness gauge allows the use of several x-ray radiation fluxes with different effective radiation energies emitted during one period of the alternating voltage supply of the x-ray tube, which will increase the accuracy of thickness measurements by a factor of 1.5-2. An X-ray thickness gauge containing an X-ray tube with a power source, mounted on one side of the test sample, and a detector mounted on the other side of the sample, characterized in that, in order to improve the accuracy of the work, the power source is pulsed, and the thickness gauge is equipped with a threshold device, connected input to the output of the pulse power source, adjustable time delay elements, the inputs of which are connected to the output of the threshold device, electronic keys and pulsed current meters connected by inputs to the outputs of electronic switches, the first inputs of which are connected to the corresponding outputs of adjustable time delay elements, and the second to the output of the detector. Sources of information taken into account in the examination 1. Segalin V. G. The use of radioactive isotopes for automation in the coal industry. Gosgortekhizdat, 1960, p. 218.

2. US patent number 3717244, cl. 250-833, 1969.