Outokumpu Oy

Oxford Instruments Analytical Oy

Oxford Instruments Analtyical Oy

Erkki Sakari Kiuru

Heikki Sipilä

Heikki J Sipila

Kari T Aittoniemi

Seppo J Uusitalo

Georg C Von Alfthan

Erkki Ilmari Leinonen

Tor S Andersson

Lasse S Kahara

Seppo Vaijarvi

Aatu V Lappalainen

Kalevi Savolainen

Vaino A Paukku

For compensating for the rate dependent change of charge-to-voltage conversion factor in a drift-type radiation detector there is detected a change in a momentary photon hit rate affecting said drift-type radiation detector. A drain current flowing through an integrated amplifier of said drift-type radiation detector is changed by an amount proportional to the detected change in said momentary photon hit rate.

Method and circuit arrangement for compensating for rate dependent change of conversion factor in a drift-type radiation detector and a detector appliance

A drift detector produces an indication of an occurred hit of a quantum in the detector element. For neutralising accumulated charge in the detector element, indications of occurred hits are used to trigger pulses of deliberately increased neutralisation current into the drift detector for the duration of a limited time interval. Alternatively such triggering may be based on the operation of a timer.

Drift-type detector with limited noise level

The invention relates to a radiation detector, an arrangement and a method for an energy-dispersive detection of X-ray photons. X-ray photons are allowed to collide () in the radiation detector (), whereby there are produced () observations of the X-ray photons that collided in the detector. According to the invention, there are separately produced observations of X-ray photons () that collided in the first detector space () of the radiation detector and X-ray photons () that collided in the second detector space () of the radiation detector. The () observations of X-ray photons that collided in the first detector space () are ignored, when there is received a simultaneous observation of an X-ray photon that collided in the second detector space.

Radiation detector, arrangement and method for measuring radioactive radiation, where continuous low-energy background noise is reduced

The apparatus of the invention comprises at least two transmitter coils (3) and a respective number of receiver coils (4). The transmitter coils (3) and the respective receiver coils (4) are placed in a crosswise position with respect to each other so that the primary fields created by the transmitter coils (3) are divergent.

Pulse field metal detector with spaced, dual coil transmitter and

Disclosed is a method and an apparatus for analyzing pieces of ore for the purpose of sorting. Each piece falling by the analyzer is irradiated individually by means of two gamma radiation sources operating at different energy levels so selected that, as to the scattering effect, at one level the Compton effect is predominant and at the other level the Compton effect and the photoelectric effect compete with each other. The former effect is strongly dependent on the ordinal number of the element and, thus, by detecting with at least one detector the scattering intensities produced with the said two sources of radiation and comparing the scattering intensities with each other, the proportion of heavy elements in the ore piece can be determined and the ore piece can be classified on the basis thereof. For example, one energy dispersively operating scintillation detector can be used for detecting the scattered radiation.

Method and apparatus for analyzing ore by means of gamma radiation

The average particle size for particles distributed in a slurry is determined by transmitting at least one beam of ultrasonic rays of a certain frequency into the slurry, detecting, by separate detector means, on one hand ultrasonic radiation that passes through the slurry and, on the other hand, ultrasonic radiation scattered in the slurry, said detector means forming first and second signals corresponding to the intensities of the passed-through and the scattered radiation respectively, determining the scattering attenuation factor on the basis of said first and second signals and the total attenuation factor by using the intensity of passed-through radiation obtained with pure water, and determining the particle size with the help of the scattering attenuation factor, whereby the radio of said factor and the total attenuation factor is formed in order to eliminate influence of the slurry density. Two transmitters operating at different frequencies may be used, whereby one detector may detect passed-through radiation at one frequency and the other detector may detect scattered radiation at the other frequency.

Method and apparatus for the determination of the average particle size

In a stabilized voltage source having an actual-value voltage gauge which is temperature dependent, the overall temperature stability of the voltage source is improved by providing a reference-value voltage with an adjustable temperature coefficient, said temperature coefficient being so adjusted that it substantially compensates for the temperature dependence of the actual-value voltage gauge within the temperature range used. The reference voltage having an adjustable temperature coefficient is preferably obtained by combining a first voltage which is essentially independent of temperature with a second voltage being strongly dependent on temperature, the degree of mutual influence of said combined voltages being regulated to adjust said temperature coefficient.

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Espoo, Finland

Erkki Sakari Kiuru