JPH03210453A - neutron moisture meter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a neutron moisture meter for online measurement, and is particularly suitable for measuring moisture content over a wide range from low to high moisture content with high accuracy. Regarding neutron moisture meter.

[Conventional technology]

Conventional devices, as described in JP-A-62-116242, measured only the thermal neutrons coming out of the hopper by utilizing the scattering of fast neutrons by the object to be measured in the hopper and the deceleration caused by reflection. In the case of objects to be measured with extremely low moisture content, the thermal neutron detector detects only a small number of signals, and there is a limit to accurate measurements.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not give consideration to improving the measurement accuracy in the range where the moisture content is extremely low, and because there are few signals (pulses) in the range where the moisture content is extremely low, measurement errors are affected by statistical fluctuations etc. The problem was that it was big.

An object of the present invention is to provide a neutron moisture meter that can accurately measure water content over a wide range by increasing the number of signals (pulses) in a range where the water content is extremely low and reducing measurement errors.

[Means to solve the problem]

In order to achieve the above object, a fast neutron source is installed on the opposite side of the neutron detector to the hopper, and a fast neutron detector is added to detect the fast neutrons that have passed through.

Furthermore, in order to achieve the above object, the calculation section is provided with a detection amount selection function in a low moisture content area and a high moisture content area.

[Effect]

When the moisture content of the object to be measured in the hopper is around 0%, fast neutrons emitted from the fast neutron source pass through the hopper without being decelerated and are measured by a fast neutron detector. On the other hand, as the water content increases, the fast neutrons emitted from the fast neutron source are decelerated, and the signal detected by the fast neutron detector decreases.

In this way, by utilizing the characteristic that the signal (pulse) decreases as the moisture content increases, with the maximum moisture content being 0%, it is possible to reduce statistical errors near the moisture content of 0%, and improve measurement accuracy. can be raised. On the other hand, in a thermal neutron detector, on the contrary, the number of signals (pulses) increases as the water content increases, with the minimum value at 0% water content. By properly utilizing these two characteristics, moisture content can be measured over a wide range with high accuracy.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The fast neutrons emitted from the fast neutron source 1 in FIG. The signal is amplified, measured by the counting rate meter 7, and sent to the calculation section 9. On the other hand, fast neutrons that have passed through the hopper 2 without being decelerated are detected by the fast neutron detector 4, amplified by the preamplifier 6, converted to a count rate by the count rate meter 8, and sent to the calculation section 9. Each characteristic has characteristics as shown in FIG. 2, and is inputted in advance as a moisture content calculation formula to the calculation section 9. The calculation unit 9 always uses the signal with the larger count rate to calculate the water content, and when the number of signals from the thermal neutron detector side is large, it uses the characteristics of the thermal neutron detector to calculate the water content. Conversely, when the number of signals from the fast neutron detector side is large, the water content is calculated using the characteristics of the fast neutron detector. According to this embodiment, since signal processing with a high counting rate can be performed over a wide range of moisture contents, it is possible to accurately measure from low moisture contents to high moisture contents.

〔Effect of the invention〕

According to the present invention, since signal processing can be performed at a high counting rate over a wide range from low moisture content to high moisture content, moisture content can be measured with high accuracy.

[Brief explanation of drawings]

Fig. 1 is a measurement system diagram of one embodiment of the present invention, and Fig. 2 is a measurement system diagram of an embodiment of the present invention.
It is a figure showing the characteristic of the moisture content-count rate characteristic of each detector of a figure. 1... Fast neutron source, 2... Hopper, 3... Thermal neutron detector, 4... Fast neutron detector, 5.6... Preamplifier, factor diagram ice-containing key →

Claims (1)

[Claims] 1. A neutron moisture meter comprising a hopper, a fast neutron source, a thermal neutron detector, a preamplifier, a count rate meter, and a calculation section, which is characterized in that a fast neutron detector is added.