SU901704A1

SU901704A1 - Cryostat for semiconductor radiation detector

Info

Publication number: SU901704A1
Application number: SU782686959A
Authority: SU
Inventors: Владимир Петрович Гиманов; Вальтер Иванович Захарченко; Анатолий Григорьевич Сиухин; Дмитрий Алексеевич Гоганов
Original assignee: Предприятие П/Я М-5912
Priority date: 1978-11-21
Filing date: 1978-11-21
Publication date: 1982-01-30

Description

II

Изобретение относитс к приборам дл исследовани спектров излучени , в частности к приборам с охлаждаемыми полупроводниковыми детекторами рентгеновского и гамма-излучени и предназначено, например, дл использовани в корпускул рно-зондовых приборах .The invention relates to devices for studying radiation spectra, in particular to devices with cooled semiconductor detectors of x-rays and gamma rays, and is intended, for example, for use in corpuscular-probe devices.

Наиболее близким к предлагаемому вл етс криостат дл полупроводникового детектора излучени , содержащий внутренний сосуд Дьюара дл хладагента , наружный вакуумный кожух с камерой дл детектора, хладопровод, один конец которого соединен с внутренним сосудом, а другой - с детектором , и установленный в вакуумном кожухе криоадсорбционный насос в виде сло сорбента 1The closest to the present invention is a cryostat for a semiconductor radiation detector, containing an internal Dewar vessel for a refrigerant, an external vacuum jacket with a detector chamber, a refrigerant duct, one end of which is connected to the internal vessel and the other with a cryoadsorption pump in the form of a layer of sorbent 1

В криостатах такой конструкции детектор излучени будет стабильно работать в течение длительного времени только в том случае, если длина хладопровода незначительна, т. е, детектор должен быть размещен вблизи сосуда с хладагентом. В насто щее врем развитие некоторых отраслей науки и техники, например, электронно-зондовой микроскопии и микроанализа предъ вл ет жесткие требоват ни к конструкции охлаждаемых полупроводниковых детекторов.А именно рабоча камера детектора должна быть возможно меньшего диаметра (10-15 мм) In cryostats of this design, the radiation detector will work stably for a long time only if the length of the refrigerant pipe is small, i.e., the detector must be placed near the refrigerant vessel. At present, the development of certain branches of science and technology, for example, electron-probe microscopy and microanalysis, makes it hard to design cooled semiconductor detectors. It is the working chamber of the detector that should be as small as possible (10-15 mm)

10 и находитьс на значительном (в некоторых случа х до нескольких метров) рассто нии от сосуда с хладагентом и средств откачки. В таких случа х известные конструкции криостатов не 10 and be at a considerable (in some cases up to several meters) distance from the vessel with the refrigerant and the pumping means. In such cases, the known designs of cryostats are not

1S обеспечивают стабильность работы полупроводниковых детекторов более, чем в- течение 12 мес цев, так как в зоне расположени детектора (в рабо2Q чей камере) вакуум хуже, чем в зоне, прилегающей к насосу.1S ensure the stability of the semiconductor detectors for more than 12 months, since the vacuum is worse in the zone where the detector is located (in whose chamber) the vacuum is worse than in the zone adjacent to the pump.

Claims

At an insufficiently high vacuum, sorption of the cooled surface of the detector of residual gas molecules, in particular limited substances, occurs, which increases the leakage currents of the detector, worsens its energy resolution, and the ratio of counting in spectral peaks to counting in the background Over time, this leads to a noticeable decrease in the analysis sensitivity especially for light elements. The purpose of the invention is to increase the service life with stable operation of the cooled radiation detector by preventing contamination of the detector. This goal is achieved by the fact that in a cryostat for a semiconductor radiation detector, the end of the coolant, connected to the detector, is filled with a helical groove in which the sorbent layer is placed. FIG. 1 shows a cryostat, a general view; in fig. 2 — node I in FIG. 1 Cryostat contains external vacuum casing 1 with working chamber 2, vacuum volume 3 | communicating with the volume of the working chamber 2, radiation screen A, cryoadsorption pump 5 serving as a means for pumping out the vacuum volume 3 of the casing 1, the inner vessel 6 with the refrigerant 7, the coolant 8 with the outer screw groove, inside which is placed a layer of sorbent 9i sec 10 and a semiconductor detector 11 mounted on the end of the cold conductor 8. The device operates as follows. When refrigerant 7 is poured into the inner vessel 6, the lower part of the vessel 6 is first cooled and the cryoadsorption pump 5t comes into action, which improves the vacuum in the vacuum rpm, at least 3 to 133.3 10 Na and pulls the air and organic molecules out of the working volume. cameras

2. At the same time, due to the heat conduction, chlable doprovod 8 begins to cool, one end of which is in direct contact with refrigerant 4 by agent T. As the temperature decreases on the refrigerant conductor 8, the turns of the groove with the sorbent layer 9 and in working chamber 2 a higher vacuum is created. In this case, the detector I1 has not yet had time to cool down to the necessary negative temperatures. This principle of cooling the detector protects its work surface from contamination. The proposed technical solution makes it possible to significantly increase the service life of a semiconductor detector while maintaining stable operation over the entire life cycle. The use of the present invention allows to increase the warranty service life of the detector up to 18 months. This very significantly reduces the cost of replacing a detector in the device, as the cost of a single semiconductor detector, for example. Si (Li) is at least 10 thousand rubles. A cryostat for a semiconductor radiation detector, comprising an outer vacuum jacket with a chamber for an detector, an internal refrigerant vessel, a refrigerant line, one end of which is connected to an internal vessel, and the other with a detector, and a cryoadsorption pump installed in a vacuum jacket in the form of a sorbent layer, characterized in that, in order to increase the service life due to the prevention of contamination of the detector, the end of the refrigerant line connected to the detector is made with a helical groove in which the layer with rbenta. Information sources. Considered during examination 1. Nuclear Instr. and meth. 101, 1972, p. 113-125,