SU1491199A1 - Neutron moisture meter - Google Patents

Description

(A6) 07.02,92. Bion. N 5

(21) 4349533/25.,,

(22) 09/30/87

(72) L.I.Vessky, A.I.Beskorsky, L.I.Lerner, A.Z. Mints and A.D. Miroshnichenko. (53) 550.83 (088.8)

(56) Stroykovsky A.K. Moisture meter for blast furnace coke. - Cherna metallurgists. Bulletin of scientific and technical information, 1977, K 2 (790), pp.52-53.

Cl I patent No. 2999160, Cl. 250-269, 1961. L

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, (54) YATRON MOISTURE METER

(57) The invention relates to neutron moisture meters, mainly neutron moisture meters for soils. The aim of the invention is to increase the sensitivity, reduce the mass of the meter and reduce the radiation hazard. The detector of slow neutrons is placed together with a source of fast neutrons inside the probe body. Pa of the cathode of the detector is made annular compression with a smooth transition to a larger diameter. The source of fast neutrons, made in the form of a part of a ring, is installed in a narrowing and does not go beyond the dimensions of the detector. The diameter of the detector is approximately equal to the internal diameter of the probe, which increases the sensitivity of the recording part of the moisture meter. This will use a source of lesser activity and eliminate the hydrogen-containing protection, thereby achieving the indicated goal. I zp f-ly, 1 ill.

The invention relates to neutron moisture meters, primarily to neutron soil moisture meters.

The aim of the invention is to increase chuyshpitelnosti, reducing the mass of the meter and reduce radiation onacHocTir.

The drawing shows a neutron probe measuring humidity, a longitudinal section.

Inside the probe case 1, a slow neutron detector 2 and an electronic unit 3, which serves to amplify the detector pulses 2, are placed. The probe also compresses a high voltage source needed to power the detector, the probe is connected to a pulse recorder (not shown) with a cable 4. Cylindrical the cathode 5 of the detector 2 is at the same time its shell. In the middle of the cathode 5 made sug

living in the form of an annular groove 6, in which the source of 7 fast neutrons is placed, is not Bystagup (for the dimensions of detector 2. Source 7 is made in the shape of a half ring, although it can also be made in several parts of a ring (torus). 6 one of the known methods, for example, glued.

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It is a 2 nlt chickpea toncap metal ichp-skp thread R, which serves as a node of the detector. The volume of the detector zapolgei gas - isotope Helig CHe).

In order to avoid breakdown, the shortest distance between the cathode and anode in the recess region must be at least 0.7 cathode radius. To prevent a decrease in the sensitivity of the detector, it is also necessary to limit the area of the annular groove. It should not exceed 5% of the cathode,

P () can be designed as a measure - HI 1H detector, in which the cathode has a diameter of 30 mm. The depth of the annular groove is 3.5 mm. It contains a source of fast neutrons (Pu-Be), which has the shape of a torus half with a gaiter, and dimensions (greatest): length 30 mm, height 15 mm, diameter 3, 2 mm, ..,

Moisture meter works as follows

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The probe is lowered into the well drilled in the soil, and a predetermined depth. Emitted by the source 7

fast neutrons are scattered and slowed down in the environment. Slowed neutrons diffuse in all

In this case, some part of them goes into the detector. The chosen combination of the cathode shape and the location of the neutron source makes it possible to increase the diameter of the detector to the diameter of the probe, limited by the internal size of the casing pipe 5 well, into which the probe is immersed. As a result, the sensor increases.

iii-icTb, it appears that the power of the source is reduced and, consequently, to reduce the radiation and mass of the source, use it in the transport or non-working position of the probe.

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Claims (1)

Invention Formula i, Neutron detector of humidity, made in the form of a probe, containing a cylindrical gas; and a detector of slow neutrons, source fast neutrons, mounted on the detector in its middle part, and the electronic unit, the probe is connected by cable with recording equipment, characterized in that, in order to increase the sensitivity, reduce the mass of the meter and reduce the radiation hazard, the cathode of the detector is made with a recess located half the detector length is not more than 15% of the cathode cross-sectional area; the minimum anode-cathode distance in the area of intensification should be at least 0.7 R, where R is the radius of the cathode, and the fast neutron source is installed in a recess the cathode is flush with the cylindrical surface of the detector, 2, The meter according to claim 1, about tl and - due to the fact that the recess. cions in the cathode of the slow neutron detector are made in the form of an annular constriction with a smooth transition to larger diameter, and the source of fast neutrons is made in the form of torus elements.