Abstract: A read network topology for a matrix output device with a number of outputs determined by cross-joining “m” rows and “n” columns comprises a basic filtering block replicated for all the outputs and separately assigned to each of the outputs; each filtering block contains two filtering circuits that have a common input connection to the assigned matrix output and that provide two separate symmetrical and filtered outputs; all the row outputs (i) from the same row “i” but from different columns are interconnected to an input of an amplifier linked to row “i”, and all the column outputs (j) from the same column “j” but from different rows are connected together to an input of an amplifier linked to column “j”, the complete topology appearing when “i” and “j” are expanded in the respective intervals thereof.

Abstract: A method for controlling filament current of a computed tomography (CT) tube includes: detecting a present tube current of the CT tube and assigning the present tube current to a feedback value, calculating a difference between a set value of the tube current and the feedback value and assigning the difference to an error value, assigning a target upper bound value to a present filament current when the error value is greater than an first error threshold, and assigning a target lower bound value to the present filament current when the error value is less than a second error threshold, wherein the target upper bound value is greater than the target lower bound value, the first error threshold is greater than 0, and the second error threshold is less than 0.

Abstract: A system is provided. The system includes a conveyor apparatus configured for conveying a material and a water content measurement system positioned about the conveyor apparatus for determining water content in the material. A dimension characteristic measurement system for detecting one or more dimension characteristics of the material is provided and a computer device is configured to manipulate data received from the water content measurement system and the dimension characteristic measurement system to determine a water content of the material.

Abstract: A radiation detector module includes a radiation detector, power source and wireless communication elements all housed within a flame-proof enclosure. The enclosure has a portion through which wireless transmissions can pass. The radiation detector module may be suitable for use in a hazardous area containing a potentially explosive gas mixture.

Abstract: A three dimensional radiation measurement scanning system includes a circular drive operable with horizontal and vertical drives for moving a radiation detector through first, second and third orthogonal axes in a three dimensional scanning of the detector in a water tank. Motor are coupled to the drives and activated by a controller for providing the movement of the radiation detector which providing radiation field sensing signals for locations of the detector throughout the tank. A reference detector is fixed for comparing its radiation field measurements with those of the scanned radiation detector. An offset mount carries the radiation detector allowing it to be extended beyond the circular ring gear during horizontal movement of the radiation detector and thus position the radiation detector at wall surfaces of the water tank.

Abstract: To attain objects to reduce the spread of electrons as compared with a conventional one without degrading the multiplication factor of electrons; to provide a large electron multiplication factor; and to improve positional resolution, there is provided a gas electron multiplier using interaction between radiation and gas through photoelectric effects including: a chamber filled with gas and a single gas electron multiplication foil arranged in the chamber wherein the gas electron multiplication foil is made of a plate-like multilayer body composed by having a plate-like insulation layer made of a macromolecular polymer material having a thickness of around 100 ?m to 300 ?m and flat metal layers overlaid on both surfaces of the insulation layer, and the plate-like multilayer body is provided with a through-hole structure.

Abstract: The invention comprises a radiation and contamination monitor for the monitoring of radiation and contamination. The instrument is intrinsically safe and comprises a radiation detector, a power source, a signal processor and a display, said power source, signal processor and display being housed within a sealed instrument housing formed from a non-metallic material which is resistant to static discharge. The detector may be housed in a detachable housing for contamination monitoring.

Abstract: A radiation measurement device includes a radiation detector generating an analog signal containing pulse components, an A/D converter converting the analog signal into sampled data, an n-th power pulse discrimination unit calculating n-th power values of the sampled data to discriminate the pulse component, where n is two or more, and a pulse counter counting a number of the discriminated pulse components.

Abstract: A radiation dosimeter providing an indication of the dose of radiation to which the radiation sensor has been exposed. The dosimeter contains features enabling the monitoring and evaluating of radiological risks so that a user can concentrate on the task at hand. The dosimeter provides an audible alarm indication that a predetermined time period has elapsed, an audible alarm indication reminding the user to check the dosimeter indication periodically, an audible alarm indicating that a predetermined accumulated dose has been prematurely reached, and an audible alarm indication prior or to reaching the ¾ scale point.

Abstract: A radiation detector that utilizes an unregulated power supply as opposed to a regulated power supply, since quantitative results are not required, only an audible signal, and an unregulated power supply is less expensive than that of a regulated power supply. The radiation detector includes a Geiger-muller tube, a nine volt DC power supply, a solid state oscillator with an output of 2 kilohertz, a high voltage power supply, and an audio amplifier.

Abstract: A method for monitoring exposure time of workers involves the use of a sensor, which is carried by the workers for monitoring continually in a real-time fashion in an environment such that the results are recorded by a recorder. The an add-on or built-in timer in the sensor or the recorder is used to monitor time, which is recorded in the recorder simultaneously, so as to obtain the real-time continuous exposure level of a hazardous material in the environment.

Abstract: The present invention provides an improved thin layer nuclear density gauge comprising a gauge housing having a vertical cavity therethrough and a base, a first radiation detector located at a first position within said housing and adjacent to said base of said housing, a second radiation detector located at a second position within said housing and adjacent to said base of said housing, a vertically moveable source rod extending into said cavity of said gauge housing, a radiation source operatively positioned within a distal end of said source rod, at least one bearing operatively positioned to guide said source rod within said cavity, and means for vertically extending and retracting said source rod to a plurality of predetermined source rod positions so as to change the spatial relationship between said radiation source and said first and second radiation detectors. The source rod has a maximum radial movement of less than about 0.003 inch at each predetermined position.

Abstract: A person-specific monitor that provides sensor information regarding hazards to which the person is exposed and means to geolocate the person at the time of the exposure. The monitor also includes means to communicate with a remote base station. Information from the monitor can be downloaded at the base station for long term storage and analysis. The base station can also include means to recharge the monitor.

Abstract: A radiation beam scanner system employs a peak detection methodology to measure the intensity and distribution of radiation produced by a medical linear accelerator. The scanner system combines the capability to perform scanning measurements with the capability to perform high accuracy calibrations of the linear accelerator. The system employs two ion chamber detectors, signal and reference, with the signal detector positioned within a tank of water (phantom tank). As the water is irradiated by the linear accelerator, the signal detector is continuously moved within the water by means of electrical stepper motors as the reference detector remains stationary at some point within the radiation beam. The reference detector output is compared to a predetermined threshold and, when the threshold is reached, a peak detector circuit monitors the signal detector output for a radiation pulse peak.

Abstract: A method and apparatus for monitoring ionizing radiation comprising radiation detectors in electrical connection with an isotopic analyzer and a device for producing chords to which each isotope is mapped so that the device produces a unique chord for each isotope. Preferably the chords are pleasing to the ear, except for chords representing unexpected isotopes, and are louder or softer depending on the level of radioactivity produced by each isotope, and musical instrument voices may be simulated in producing the chords as an aid to distinguishing similar-sounding chords. Because of the representation by chords, information regarding the level and composition of the radiation in an area can be conveyed to workers in that area more effectively and yet without distracting them.

Abstract: Small, light-weight portable radiation measurement apparatus provides accurate quantitative measurment of radiation dosage and dosage rates. Such apparatus, referred to as a dosimeter, is housed in a ruggedized housing that is only about 1/2 the volume of a package of cigarettes, may easily be clipped to clothing or carried in a shirt pocket, and is powered by a conventional alkaline AA-sized battery. Included in the housing are a geiger tube for detecting radiation, a high voltage power supply for providing power to the geiger tube, a counting circuit for counting geiger pulses generated by the geiger tube, a microprocessor circuit for processing the geiger pulses in accordance with a prescribed program to determine the does or dosage rate to which the geiger tube has been exposed, and a digital display that displays the dosage rates thus determined. The microprocessor program is stored in memory circuits, included as part of the microprocessor circuit.

Abstract: A visual display for indicating a level of ionizing radiation is mounted on a portion of an item of headwear, such as safety goggles, at a position within the peripheral field of vision of a wearer. Such a display advises a wearer of a level of radiation, including warning levels, in real time without requiring activity on the part of the wearer. In one embodiment, an ionizing radiation detector, accompanying circuitry, and the visual display are mounted on the glasses, such as on the frame. In another embodiment, a commercially-available detector is used to provide an output from a location remote from the headwear to actuate the visual display on the headwear. Various circuit embodiments are also disclosed.

Abstract: A flame and radiation detector system is provided with programmable logic to read the detector and control the detector voltage supply in order to make possible a high counting rate. This makes the radiation detecting system fast and reliable by increasing the signal to noise ratio.

Abstract: An instrument for measuring ionization radiation acting upon a person is mounted in a housing which can be carried in the pocket of a garment, the housing includes a forwardly projecting portion having a radiation detector mounted in the forwardmost portion thereof, so as to be exposed to a wide angle of ionizing radiation. A display unit is located in an upper wall of the housing facing in a direction which may be read by the person.

Abstract: This invention relates to a charged particle beam-dosimeter comprising an ionization chamber which produces an ionization current having a magnitude proportional to the dose of a charged particle beam, an operational amplifier which is connected to the output side of the ionization chamber, a capacitor which is connected in parallel with the operational amplifier, and a comparator which is connected to the output terminal of the operational amplifier, wherein charges are collected in the capacitor on the basis of the ionization current having flowed from the ionization chamber, and when the output potential of the operational amplifier has become a predetermined voltage, one pulse is generated so as to be counted and simutaneously to extinguish the charges stored in the capacitor.

Abstract: An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

Abstract: A detector for airborne alpha radiation includes a ion pulse collecting chamber connected to a phase shifted, 100% negative feedback electrometer circuit. The ion pulse chamber includes a probe surrounded by an 80% open grid, with the spacing between the probe and the grid providing no greater than about 50 ms transit time before collection and having a capacitance of less than 1 pf. The field strength between the probe and the grid is less than 10 V/cm. The ion pulse chamber is contained within a vented cabinet. If it is desired to count only radon, a negative potential with respect to the grid may be applied to the cabinet to collect positively charged free ions. Alternatively, the cabinet wall can be made positive with respect to the grid to create a potential-well at or near the grid to provide an enhanced daughter detection mode. If the cabinet wall and the grid are the same potential, both radon and daughter alpha radiation are detected.

Abstract: A personal radiation monitor of the chirper type is provided for detecting ionizing radiation. A battery powered high voltage power supply is used to generate and apply a high voltage bias to a G-M tube radiation sensor. The high voltage is monitored by a low-loss sensing network which generates a feedback signal to control the high voltage power supply such that the high voltage bias is recharged to +500 VDC when the current pulses of the sensor, generated by the detection of ionizing radiation events, discharges the high voltage bias to +450 VDC. During the high voltage recharge period an audio transducer is activated to produce an audible "chirp". The rate of the "chirps" is controlled by the rate at which the high voltage bias is recharged, which is proportional to the radiation field intensity to which the sensor is exposed. The chirp rate sensitivity is set to be approximately 1.5 (chirps/min/MR/hr.).

Abstract: Apparatus for the continuous monitoring of levels of ionizing radiation in premises for human occupation is provided, including an enclosure for location in premises to be monitored, an ionizing radiation transducer within the enclosure and producing counts in response to radiation incidents, a power supply continuously providing an an operating potential to said radiation transducer, a time base defining monitoring intervals of at least about 5 seconds, a counter for accumulating counts during successive monitoring intervals, and alarm means responsive to the accumulated count during a monitoring interval exceeding a predetermined threshold representing a level of ionizing radiation which if continued over an extended period would expose a human being to a cumulative dosage exceeding a level deemed acceptable.

Abstract: A dosimeter that includes tissue equivalent bubbles of plastic defining volumes of gas to be ionized by radiation. One or more integrated circuits (ICs) are disposed below the volumes of gas and a collecting electrode on the IC is in direct contact with the gas. Circuitry for generating an electric field within the volume of gas moves the ions therein to the collecting electrode. The collecting electrode is part of an amplifying circuit disposed within the IC. The output from the amplifier is representative of the collected ions and therefore representative of the radiation. The signal from the amplifier is sent to an interface which conditions, buffers and stores the signal. The radiation dose and dose rate are computed in the interface. A communications section transfers that data from the dosimeter upon receipt of an externally generated data transfer command. A separate calibration and display unit calibrates the dosimeter by controlling the conditioning of the signal.

Abstract: An extended range dose-rate monitor is provided which utilizes the pulse pileup phenomenon that occurs in conventional counting systems to alter the dynamic response of the system to extend the dose-rate counting range. The current pulses from a solid-state detector generated by radiation events are amplified and shaped prior to applying the pulses to the input of a comparator. The comparator generates one logic pulse for each input pulse which exceeds the comparator reference threshold. These pulses are integrated and applied to a meter calibrated to indicate the measured dose-rate in response to the integrator output. A portion of the output signal from the integrator is fed back to vary the comparator reference threshold in proportion to the output count rate to extend the sensitive dynamic detection range by delaying the asymptotic approach of the integrator output toward full scale as measured by the meter.

Abstract: An integrated circuit comprising: a semiconductor die having an integrated circuit formed therein; a package for supporting the die and for providing electrical contact thereto, the radiation properties of the package having been characterized as follows: fabricating a detector using a semiconductor fabrication technique, the detector having substantially the same dimensions as an integrated circuit to be packaged in the packaging materia; packaging the detector using integrated circuit packaging techniques; and measuring the radiation environment of the detector.

Abstract: A remote sensing transponder system is disclosed including apparatus for sensing gamma radiation levels proximate thereto, generating a signal indicative of the sensed radiation level, and transmitting an RF Signal modulated with the generated signal to a remote receiver in response to an interrogation signal from the receiver. The transponder further includes a pressure sensing device for sensing overpressure shockwaves such as caused by a nuclear blast and further modulating the transmitted RF Signal to indicate the detection of such a shockwave.

Abstract: A beta radiation particle detector having a housing that is substantially impervious to beta radiation particles and which surroundingly encompasses an ionization chamber which is defined by electrically conductive walls is disclosed. The walls terminate in an edge which defines an opening into the ionization chamber with the opening being covered by a beta radiation pervious electrically conductive window that entraps, within the ionization chamber, a quantity of gaseous molecules which are adapted to ionize upon impact with a beta radiation particle. An electrode is disposed within the ionization chamber and has a generally shallow concave surface having a width which is substantially greater than its depth and which faces the electrically conductive window.

Abstract: Proportional detector intended to detect ionizing radiations for 2-dimension localization.This detector consists of a network of conducting wires (2) forming the anodes of an ionization chamber and operating under avalanche conditions and is characterized in that it comprises a continuous resistive collector (12) with two dimensions and located between the anode (2) wires and the cathode (1) on which the localization of an electron avalanche is effected by electrostatic induction, the reading of the data concerning the electric pulse generated by induction on the collector (12) being effected at the periphery of the latter.

Abstract: The disclosure concerns a bar dosimeter used for measuring ionizing radiation. In a hollow housing, an axially deflectible contact pin is centrally supported in a deflectible membrane. The pin and the membrane are deflectible over center to a first deflected position wherein the pin engages another contact leading to an ionizing capacitor, and to a second deflected condition, where the pin is spaced away from the contact of the capacitor. Stops supported in the housing define the first and second deflected positions of the pin and the membrane. A spring acts through an intermediate piece to normally bias the pin and the membrane to the second deflected condition where the pin is out of engagement with the contact.

Abstract: A Geiger-Mueller tube-based radiation measurement device includes circuitry for the correction of the dead time losses associated with the Geiger-Mueller tube. As the event count rate rises, the transfer function (e.g., the closed loop voltage gain) of an operational amplifier responding to an event count rate signal is modified to compensate for dead time losses experienced at high count rates. Preferably, an analog switch controlled by the event count rate signal automatically sets the voltage gain of the operational amplifier at a level corresponding to the desired amount of dead time compensation required to provide an accurate measurement of actual events. The dead time correction circuitry disclosed herein finds practical application in the use of well-known analog rate meter circuits of the charge pump type.

Abstract: A hand-powered alternator for generating an alternating voltage provides same through a rectifier to a high capacity capacitor which stores the resultant dc voltage and drives a voltage regulator to provide a constant low voltage output for a portable radiation detection instrument. The instrument includes a Geiger-Muller detector tube whose output is fed to a pulse detector and then through an event counter and LCD driver circuit to an LCD bar graph for visual display. An audio driver and an audio output is also provided. All circuitry used is low power so that the capacitor can be readily charged to a sufficient level to provide power for at least 30 minutes. A low voltage indicator is provided on the LCD display to indicate the need for manual recharging.

Abstract: A dosimeter for measuring the intensity of high energy electron, photon, or other particle radiation has ion, electron, and radiation shields about at least respectively sensitive components of the dosimeter. The entire dosimeter, therefore, can be assembled as a unit and portably placed in the radiation to be measured. Ruggedness for this desirable partability is provided by the use in the dosimeter of a pancake ionization chamber which also eliminates the need to calibrate radiologically the dosimeter.

Abstract: A radiation dose-rate monitor is provided which operates in a conventional linear mode for radiation in the 0 to 0.5 R/h range and utilizes a nonlinear mode of operation for sensing radiation from 0.5 R/h to over 500 R/h. The nonlinear mode is achieved by a feedback circuit which adjusts the high voltage bias of the proportional counter, and hence its gas gain, in accordance with the amount of radiation being monitored. This allows compression of readout onto a single scale over the range of 0 to greater than 500 R/h without scale switching operations.

Abstract: An ionization chamber of reduced size, with an end window of a diameter preferably smaller than 3 cm is mounted on the end of a hand probe containing an amplifier, the output of which goes through a cable to an indicating device. One of a set of aperture diaphragms may be slipped over the end window to reduce the area of the window transparent to beta rays. In addition to the end window, slots in the cylindrical wall of the chamber increase the solid angle through which radiation may enter the chamber. The end window and the slotted walls of the chamber are covered with tissue-equivalent material for measurement of radiation exposure dose by the electrodes of the chamber and their associated amplifier and indicator. An alternative design with a conical chamber and conical inner electrode and a smaller window provides reliable measurement, even in inhomogeneous radiation fields without the necessity of using diaphragms.

Abstract: The invention provides a device for measuring ionizing radiations, comprising a Geiger-Muller tube (1) whose high supply voltage is obtained from pulses which are emitted (by 6,7) at a constant relatively low frequency as long as a predetermined threshold is not exceeded by the intensity of the radiation and (by 6,7,4 and 32) at an increasing frequency depending on the output of the tube, after said threshold has been exceeded. Thus, alarm dosimeters having very long independent operation may be formed.

Abstract: The disclosure relates to a battery operated neutron spectrometer/dosimeter utilizing a microprocessor, a built-in tissue equivalent LET neutron detector, and a 128-channel pulse height analyzer with integral liquid crystal display. The apparatus calculates doses and dose rates from neutrons incident on the detector and displays a spectrum of rad or rem as a function of keV per micron of equivalent tissue and also calculates and displays accumulated dose in millirads and millirem as well as neutron dose rates in millirads per hour and millirem per hour.

Abstract: This invention relates to a digital radiation dosemeter comprising a detector (12) converting the ionizing radiation to electrical impulses and an electronic survey device (14) for the storage of said impulses in a dose radiation counter (18). An optoelectronic transmitter (34, 38, 40) sends the informations to an external data processing system. A binary counter (42) operates said transmitter and cooperates with a reading control circuit (43)including a photosensitive receiver (44)connected in series with a magnetic reed switch (46).

Abstract: This invention provides a high-resolution, position-sensitive, proportional-counter for ionizing radiation emanating from a surface source of ionizing radiation. There is provided a counting chamber means having an open entrance window on one side of and spaced from the source of ionizing radiation, and an anode counting wire on the other side of the open entrance window. Also, there is provided a counter wall cathode, having a delay line read-out opposite to the entrance window and spaced from the anode. A means, including several orifices for flushing a counting gas through the counting chamber means and out of the open entrance window between the source and the open entrance window, produces a stabilizing counting gas layer that does not mix with the surrounding air. This prevents the sample from being completely surrounding air. This prevents the sample from being completely enclosed so as to be charged up electrostatically.

Abstract: In a sampled radiation detector including a pulsed Geiger-Mueller detector ube the response to gamma radiation is linearized by providing an additional "reward" pulse after the second of two adjacent pulses of a pulse train generated from Geiger-Mueller pulses outputted from the detector tube during at least two consecutive sampling time periods and wherein the pulse train is thereafter time averaged to provide a measurement signal which is a linear function of the radiation field strength.

Abstract: The present invention relates to a gamma radiation detector probe with Geiger-Muller tube of the type which compensates for pulse losses of the Geiger-Muller tube due to dead time and linearizes its response to the number of pulses per unit of time in relation to the gamma radiation exposure rate, including a converter of the electric current from the Geiger tube into a current-dependent pulse frequency, an element for combining or mixing these pulses with those supplied by the Geiger tube, and logarithmic networks for adjusting the frequency of the converter in order to linearize the response of the complex.

Abstract: This invention relates to a dead time compensation circuit for a radiation detector using a Geiger-Muller tube. The Geiger-Muller tube is the most commonly used detector for measuring gamma radiation. However, they have a restricted linear range which makes it difficult to use them with digital numeric displays. The highest dose rate that can be measured is limited by the tube dead time, i.e. the interval after the initiation of a pulse during which a subsequent ionizing event does not produce a pulse. The present invention adds one or more pulses to the display counter when the Geiger-Muller tube provides two or more pulses in a given time interval (t). The dose rate or count rate is sampled at the beginning of each counting period (T) and the interval t is made proportional to the count rate. At low count rates, where dead time losses are negligible, no pulses are added. At high count rates, where t can be several times the tube dead time, counting losses of 50% can be compensated.

Abstract: A compensation circuit for gamma-radiation detectors in which the pulses are sorted into different channels based on their amplitude. Pulse dividers are provided in the lower energy channels reducing the pulse count in these channels by an amount which is a function of the average energy of pulses received by that channel. The adjusted pulse count rates in each channel are then added to give a signal proportional to the dose rate independent of the radiation energy.

Abstract: The invention relates to a device for measuring irradiation capable of modifying the charge of an electret. It is arranged in a portable cassette, between two electrodes held separated by a part and connected to a measuring circuit. A conductive shutter is movable parallel to itself and to the electret between this electret and than electrode, so as to alternately mask this electret with respect to this electrode and to render the electret visible to the electrode. The measurement exploits differences in charge of the electret read according to the movements of the shutter.

Abstract: A battery powered device which can continuously monitor and detect nuclear radiation utilizing fully integrated circuitry and which is provided with an alarm which alerts persons when the radiation level exceeds a predetermined threshold.

Abstract: A device for individually checking exposure to radiation is sensitive to the radiation and produces an alarm (acoustic and/or optical) when a threshold radiation dose is reached. An included time-measuring device furthermore warns the user when a surveillance period has expired.The radiation sensitive device may use an electret while the time-measuring device uses the drop in voltage of a battery occurring at the end of the discharge of the battery.

Abstract: A Geiger-Mueller (GM) tube coincidence loss correction circuit for automatically compensating for the dead time of the GM tube in an analog system so that the reading provided by the meter more accurately reflects the true radiation level. The electrical output pulses from the GM tube are differentiated and provided to a retriggerable one-shot multivibrator circuit which produces in response to each GM tube pulse a corresponding output pulse of predetermined duration greater than the dead time of the Geiger tube. The output pulse signal from the multivibrator circuit advances an analog ratemeter circuit and also effectively disables "time" for the duration of the output pulse by opening an analog switch connected in the discharge path of the integrating capacitor in the ratemeter circuit to maintain constant the charge thereon.

Abstract: A high resolution position sensitive radiation detector for analyzing radiation emanating from a source, constructed of a thin plate having an elongated slot with conductive edges acting as a cathode, a charged anode wire positioned within 0.5 mm adjacent the source and running parallel to the slot and centered therein, an ionizable gas ionized by radiation emanating from the source provided surrounding the anode wire in the slot, a helical wire induction coil serving as a delay line and positioned beneath the anode wire for detecting gas ionization and for producing resulting ionization signals, and processing circuits coupled to the induction coil for receiving ionization signals induced therein after determining therefrom the location along the anode wire of any radiation emanating from the source. An ionization gas of 70% Ar, 29% Isobutane, 0.6% Freon 13BI, and 0.4% Methylal is used.

Abstract: A count-rate compensating circuit is provided which may be used in a portable Geiger-Mueller (G-M) survey meter to ideally compensate for counting loss errors in the G-M tube detector. In a G-M survey meter, wherein the pulse rate from the G-M tube is converted into a pulse rate current applied to a current meter calibrated to indicate dose rate, the compensated circuit generates and controls a reference voltage in response to the rate of pulses from the detector. This reference voltage is gated to the current-generating circuit at a rate identical to the rate of pulses coming from the detector so that the current flowing through the meter is varied in accordance with both the frequency and amplitude of the reference voltage pulses applied thereto so that the count rate is compensated ideally to indicate a true count rate within 1% up to a 50% duty cycle for the detector.