Geiger-Mueller tube

• ガイガーミュラー計数管

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Geiger-Mueller counter

WordNet

1. ride or float on an inflated tube; "We tubed down the river on a hot summer day"
2. conduit consisting of a long hollow object (usually cylindrical) used to hold and conduct objects or liquids or gases (同)tubing
3. electronic device consisting of a system of electrodes arranged in an evacuated glass or metal envelope (同)vacuum_tube, thermionic vacuum tube, thermionic_tube, electron_tube, thermionic_valve
4. (anatomy) any hollow cylindrical body structure (同)tube-shaped structure
5. convey in a tube; "inside Paris, they used to tube mail"
6. place or enclose in a tube
7. provide with a tube or insert a tube into
8. the amount that a tub will hold; "a tub of water" (同)tubful
9. a large open vessel for holding or storing liquids (同)vat
10. German physicist who developed the Geiger counter (1882-1945) (同)Hans Geiger
11. of a tire; having an inner tube

PrepTutorEJDIC

1. (金属・ガラス・ゴムなどの)管,筒 / (絵の具・歯みがきなどの)チューブ / 《米》(列車・地下鉄の)トンネル / 《英》地下鉄(《米》subway) / (ラジオ・テレビなどの)真空管(vacuum tube) / (動植物の)管状器官
2. 『おけ』,たらい / 《話》'bath 2 / (また tubful)おけ1杯[の量](の…)《+of+名》 / 《話》のろくてぶかっこうな船;《俗》でぶ,太っちょ
3. 〈U〉管状の物 / 《集合的に》管類 / 〈C〉(ある長さの1本の)管

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/11/17 13:05:37」(JST)

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Plot of ion pair current against applied voltage for a cylindrical gaseous radiation detector with a central wire anode.

The Geiger–Müller tube or G–M tube is the sensing element of the Geiger counter instrument used for the detection of ionizing radiation. It was named after Hans Geiger, who invented the principle in 1908, and Walther Müller, who collaborated with Geiger in developing the technique further in 1928 to produce a practical tube that could detect a number of different radiation types.

It is a gaseous ionization detector and uses the Townsend avalanche phenomenon to produce an easily detectable electronic pulse from as little as a single ionising event due to a radiation particle. It is used for the detection of gamma radiation, X-rays, and alpha and beta particles. It can also be adapted to detect neutrons. The tube operates in the "Geiger" region of ion pair generation. This is shown on the accompanying plot for gaseous detectors showing ion current against applied voltage.

Whilst it is a robust and inexpensive detector, the G–M is unable to measure high radiation rates efficiently, has a finite life in high radiation areas and is unable to measure incident radiation energy, so no spectral information can be generated and there is no discrimination between radiation type.

Principle of operation

Visualisation of the spread of Townsend avalanches by means of UV photons. This mechanism allows a single ionising event to ionise all the gas surrounding the anode by triggering multiple avalanches.

Detection of higher energy gamma in a thick-walled tube. Secondary electrons generated in the wall can reach the fill gas to produce avalanches. Multiple avalanches omitted for clarity

The tube consists of a chamber filled with an inert gas at low-pressure (about 0.1 atmosphere). The chamber contains two electrodes, between which there is a potential difference of several hundred volts. The walls of the tube are either metal or have their inside surface coated with a conductor to form the cathode, while the anode is a wire in the center of the chamber.

When ionizing radiation strikes the tube, some molecules of the gas are ionized, either directly by the incident radiation or indirectly by means of secondary electrons produced in the walls of the tube. This creates positively charged ions and electrons, known as ion pairs, in the fill gas. The strong electric field created by the tube's electrodes accelerates the positive ions towards the cathode and the electrons towards the anode. Close to the anode in the "avalanche region" the electrons gain sufficient energy to ionize additional gas molecules and create a large number of electron avalanches which spread along the anode and effectively throughout the avalanche region. This is the "gas multiplication" effect which gives the tube its key characteristic of being able to produce a significant output pulse from a single ionising event.

If there were to be only one avalanche per original ionising event, then the number of excited molecules would be in the order of 10⁶ to 10⁸. However the production of multiple avalanches results in an increased multiplication factor which can produce 10⁹ to 10¹⁰ ion pairs. The creation of multiple avalanches is due to the production of UV photons in the original avalanche, which are not affected by the electric field and move laterally to the axis of the anode to instigate further ionising events by collision with gas molecules. These collisions produce further avalanches, which in turn produce more photons, and thereby more avalanches in a chain reaction which spreads laterally through the fill gas, and envelops the anode wire. The accompanying diagram shows this graphically. The speed of propagation of the avalanches is typically 2–4 cm per microsecond, so that for common sizes of tubes the complete ionisation of the gas around the anode takes just a few microseconds. This short, intense pulse of current can be measured as a count event in the form of a voltage pulse developed across an external electrical resistor. This can be in the order of volts, thus making further electronic processing simple.

The discharge is terminated by the collective effect of the positive ions created by the avalanches. These ions have lower mobility than the free electrons due to their higher mass and remain in the area of the anode wire. This creates a "space charge" which counteracts the electric field which is necessary for continued avalanche generation. For a particular tube geometry and operating voltage this termination always occurs when a certain number of avalanches have been created, therefore the pulses from the tube are always of the same magnitude regardless of the energy of the initiating particle. Consequently, there is no radiation energy information in the pulses which means the Geiger–Muller tube cannot be used to generate spectral information about the incident radiation.

Pressure of the fill gas is important in the generation of avalanches. Too low a pressure and the efficiency of interaction with incident radiation is reduced. Too high a pressure, and the “mean free path” for collisions between accelerated electrons and the fill gas is too small, and the electrons cannot gather enough energy between each collision to cause ionisation of the gas. The energy gained by electrons is proportional to the ratio “e/p”, where “e” is the electric field strength at that point in the gas, and “p” is the gas pressure.

Types of tube

Broadly, there are two main types of geiger tube construction.

End window type

Schematic of a Geiger counter using an "end window" tube for low-penetrating radiation. A loudspeaker is also used for indication

For alpha particles, low energy beta particles, and low energy X-rays, the usual form is a cylindrical end-window tube. This type has a window at one end covered in a thin material through which low-penetrating radiation can easily pass. Mica is a commonly used material due to its low mass per unit area. The other end houses the electrical connection to the anode.

Pancake tube

Pancake G–M tube, the circular concentric anode can clearly be seen.

The pancake tube is a variant of the end window tube, but which is designed for use for beta and gamma contamination monitoring. It has roughly the same sensitivity to particles as the end window type, but has a flat annular shape so the largest window area can be utilised with a minimum of gas space. Like the cylindrical end window tube, mica is a commonly used window material due to its low mass per unit area. The anode is normally multi-wired in concentric circles so it extends fully throughout the gas space.

Windowless type

This general type is distinct from the dedicated end window type, but has two main sub-types, which use different radiation interaction mechanisms to obtain a count.

Thick walled

A selection of thick walled G–M tubes for gamma detection. The largest has an energy compensation ring; the others are not energy compensated

Used for high energy gamma detection, this type generally has an overall wall thickness of about 1-2 mm of chrome steel. Because most high energy gamma photons will pass through the low density fill gas without interacting, the tube uses the interaction of photons on the molecules of the wall material to produce high energy secondary electrons within the wall. Some of these electrons are produced close enough to the inner wall of the tube to escape into the fill gas. As soon as this happens the electron drifts to the anode and an electron avalanche occurs as though the free electron had been created within the gas. The avalanche is a secondary effect of a process that starts within the tube wall; the avalanche is not the effect of radiation directly on the gas itself.

Thin walled

Thin walled tubes are used for:

• high energy beta detection, where the beta enters via the side of the tube and interacts directly with the gas, but the radiation has to be energetic enough to penetrate the tube wall. Low energy beta, which would penetrate an end window, would be stopped by the tube wall.
• Low energy gamma and X-ray detection. The lower energy photons interact better with the fill gas so this design concentrates on increasing the volume of the fill gas by using a long thin walled tube and does not use the interaction of photons in the tube wall. The transition from thin walled to thick walled design takes place at the 300–400 KeV energy levels. Above these levels thick walled designs are used, and beneath these levels the direct gas ionisation effect is predominant.

Neutron detectors

G–M tubes will not detect neutrons since these do not ionise the gas. However, neutron-sensitive tubes can be produced which either have the inside of the tube coated with boron, or the tube contains boron trifluoride or helium-3 as the fill gas. The neutrons interact with the boron nuclei, producing alpha particles, or directly with the helium-3 nuclei producing hydrogen and tritium ions and electrons. These charged particles then trigger the normal avalanche process.

Gas mixtures

The main component of the gas fill mixture is an inert gas such as helium, argon or neon, in some cases in a Penning mixture, and a "quench" gas of 5–10% of an organic vapor or a halogen gas to prevent multiple pulsing. The halogen-filled G–M tube was invented by Sidney H. Liebson in 1947 and has several advantages over the tubes with older organic mixtures. The halogen tube discharge takes advantage of a metastable state of the inert gas atom to more-readily ionize a halogen molecule than an organic vapor, enabling the tube to operate at much lower voltages, typically 400–600 volts instead of 900–1200 volts. It also has a longer life than tubes quenched with organic compounds, because the halogen ions can recombine while the organic vapor is gradually destroyed by the discharge process (giving the latter a life of around 10⁸ events). For these reasons, the halogen-filled tube is now the most common.

Geiger plateau

The Geiger plateau is the voltage range in which the GM tube operates in its correct mode. If a G–M tube is exposed to a steady radiation source and the applied voltage is increased from zero, it follows the plot of ion current shown in this article. In the "Geiger region" the gradient flattens; this is the Geiger plateau.

Depending on the characteristics of the specific tube (manufacturer, size, gas type, etc.) the voltage range of the plateau will vary. In this region, the potential difference in the counter is strong enough to allow the creation of multiple avalanches. A lower voltage is not sufficient to cause a complete discharge along the anode, and individual Townsend avalanches are the result, and the tube tries to act as a proportional counter. If the applied voltage is higher than the plateau, a continuous glow discharge is formed and the tube cannot detect radiation.

The plateau has a slight slope caused by increasing sensitivity to low energy radiation as the voltage increases. Normally when a particle ionizes gas atoms, complete ionization of the gas occurs. But for a low energy particle, it is possible that the kinetic energy in addition to the potential energy of the voltage are insufficient for the avalanche to occur and the ion recombines. As applied voltage rises, the threshold for the minimum radiation response falls, thus the counter's sensitivity rises; giving rise to the slope.

The counting rate for a given radiation source varies slightly as the applied voltage is varied and to prevent this, a regulated voltage is used. However, it is normal to operate the tube in the middle of the plateau to allow for variations in the tube supply voltage.

Quenching and dead time

Dead time and recovery time in a Geiger Muller tube. The tube can produce no further pulses during the dead time, and is able to produce only pulses of limited height until the recovery time elapses.

The ideal G–M tube should produce a single pulse on entry of a single ionising particle. It must not give any spurious pulses, and must recover quickly to the passive state. Unfortunately for these requirements, when positive argon ions reach the cathode and become neutral argon atoms again by obtaining electrons from it, the atoms can acquire their electrons in enhanced energy levels. These atoms then return to their ground state by emitting photons which can in turn produce further ionisation and hence cause spurious secondary pulse discharges. If nothing were done to counteract it, ionisation could even escalate, causing a so-called current "avalanche" which if prolonged could damage the tube. Some form of quenching of the ionisation is therefore essential.

The disadvantage of quenching is that for a short time after a discharge pulse has occurred (the so-called dead time, which is typically 50–100 microseconds), the tube is rendered insensitive and is thus temporarily unable to detect the arrival of any new ionising particle. This effectively causes a loss of counts at sufficiently high count rates and limits the G–M tube to a count rate of between 10⁴ to 10⁵ counts per second, depending on its characteristic. A consequence of this is that ion chamber instruments were sometimes preferred for higher count rates, however the modern application of "electronic quenching" (see below) can extend this upper limit considerably.

Chemical quenching

Self-quenching or internal-quenching tubes stop the discharge without external assistance, by means of the addition of a small amount of a polyatomic organic vapor such as butane or ethanol, or alternatively a halogen such as bromine or chlorine.

If a poor diatomic gas quencher is introduced to the tube, the positive argon ions, during their motion toward the cathode, would have multiple collisions with the quencher gas molecules and transfer their charge and some energy to them. Thus, neutral argon atoms would be produced and the quencher gas ions in their turn would reach the cathode, gain electrons therefrom, and move into excited states which would decay by photon emission, producing tube discharge. However, effective quencher molecules, when excited, lose their energy not by photon emission, but by dissociation into neutral quencher molecules. No spurious pulses are thus produced.

External quenching

External quenching, sometimes also called "active quenching" or "electronic quenching", uses high speed control electronics to rapidly remove and re-apply the high voltage between the electrodes after each discharge peak. This results in faster quenching of the tube than using the effect of gas alone, and allows for greatly increased tube lifetimes.

A technique known as "time-to-first-count" is sometimes used in conjunction with this to greatly increase the maximum count rate of the tube.

Fold-back

One consequence of the dead time effect is the possibility of a high count rate continually triggering the tube before the recovery time has elapsed. This may produce pulses too small for the counting electronics to detect and lead to the very undesirable situation whereby a G–M counter in a very high radiation field is falsely indicating a low level. This phenomenon is known as "fold-back". An industry rule of thumb is that the discriminator circuit receiving the output from the tube should detect down to 1/10 of the magnitude of a normal pulse to guard against this. Additionally the circuit should detect when "pulse pile-up " has occurred, where the apparent anode voltage has moved to a new dc level through the combination of high pulse count and noise. The electronic design of Geiger–Muller counters must be able to detect this situation and give an alarm; it is normally done by setting a threshold for excessive tube current.

Detection efficiency

The efficiency of detection of a G–M tube varies with the type of incident radiation. Tubes with thin end windows have very high efficiencies (can be nearly 100%) for high energy beta, though this drops off as the beta energy decreases due to attenuation by the window material. Alpha particles are also attenuated by the window. As alpha particles have a maximum range of less than 50 mm in air, the detection window should be as close as possible to the source of radiation. The attenuation of the window adds to the attenuation of air, so the window should have a density as low as 1.5 to 2.0 mg/cm² to give an acceptable level of detection efficiency. The article on stopping power explains in more detail the ranges for particles types of various energies. The counting efficiency of photon radiation (gamma and X-rays above 25 keV) depends on the efficiency of radiation interaction in the tube wall, which increases with the atomic number of the wall material. Chromium iron is a commonly used material, which gives an efficiency of about 1% over a wide range of energies.

Energy compensation

Comparative response curves for GM tube with and without radiation energy compensation

Thin-walled glass G–M tube showing a spiral wire cathode. The tape bands are for fixing compensating rings

Thin-walled glass G–M tube with energy compensating rings fitted. The complete assembly fits into the aluminium housing.

If a G–M tube is to be used for gamma or X-ray dosimetry measurements the energy of incident radiation, which affects the ionising effect, must be taken into account. However individual pulses from a G–M tube do not carry any energy information. A solution is to assign a radiation dose to each counting event, so the tube characteristic relates the number of counts to the intensity of incident radiation.

At low photon energy levels the response increases as low energy photons have a greater interaction with the fill gas than high energy photons. The tube therefore has an increased response for radiation which has a lower dose rate, and a correction must be applied to prevent an incorrect high reading for low energy photons. This discrepancy can be 2–3 times greater or more, and for a thick-walled tube usually peaks at about 60 keV, where radiation interactions with the gas are still large, but the shielding effect of the wall has not become dominant.

This correction is achieved by 'energy compensation' of the tube, which modifies the number of count events in accordance with the energy of the incident radiation by using an external filter collar of energy absorbing material. The collar has an increased attenuation of low energy gamma, and so compensates for the increased energy response of the naked tube at those levels. The aim is that sensitivity/energy characteristic of the tube should be matched by the absorption/energy characteristic of the filter. This results in a more uniform response over the stated range of detection energies for the tube.

Lead and tin are commonly used materials, and a simple filter effective above 150 keV can be made using a continuous collar along the length of the tube. However, at lower energy levels this attenuation can become too great, so air gaps are left in the collar to allow low energy radiation to have a greater effect. In practice, compensation filter design is an empirical compromise to produce an acceptably uniform response, and a number of different materials and geometries are used to obtain the required correction.

See also

• Dosimeter
• Geiger counter
• Gaseous ionization detectors
• Ionization chamber
• Stopping power of radiation particles

References

External links

Patents

• U.S. Patent 1,995,018, H. J. Spanner, "Gas Filled Tube"
• U.S. Patent 2,257,827, G. J. Weissenberg, "Electron Discharge Tube"
• U.S. Patent 2,521,315, J. A. Victoreen, "Geiger tube"
• U.S. Patent 2,542,440, J. A. Victoreen, "Geiger tube"

Other

• Commercial FAQ sheet on choosing Geiger–Müller tubes
• Geiger counter history
• IAEA Practical Radiation Technical Manual

UpToDate Contents

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English Journal

• Role of dicentric analysis in an overarching biodosimetry strategy for use following a nuclear detonation in an urban environment.

• Blumenthal DJ1, Sugarman SL, Christensen DM, Wiley AL, Livingston GK, Glassman ES, Koerner JF, Sullivan JM, Hinds S.Author information 1*U.S. Department of Energy, 1000 Independence Ave SW, Washington,DC 20585; †Radiation Emergency Assistance Center/Training Site, PO Box 117, MS-39, Oak Ridge, TN 37831; ‡Oak Ridge Associated Universities, 4301 Wilson Boulevard, Arlington, VA 22203; §U.S. Department of Health and Human Services, 200 Independence Ave SW, Washington, DC 20201; **Armed Forces Radiobiology Research Institute, 8901 Wisconsin Avenue, Bethesda, MD 20889.AbstractIn the moments immediately following a nuclear detonation, casualties with a variety of injuries including trauma, burns, radiation exposure, and combined injuries would require immediate assistance. Accurate and timely radiation dose assessments, based on patient history and laboratory testing, are absolutely critical to support adequately the triage and treatment of those affected. This capability is also essential for ensuring the proper allocation of scarce resources and will support longitudinal evaluation of radiation-exposed individuals and populations. To maximize saving lives, casualties must be systematically triaged to determine what medical interventions are needed, the nature of those interventions, and who requires intervention immediately. In the National Strategy for Improving the Response and Recovery for an Improvised Nuclear Device (IND) Attack, the U.S. Department of Homeland Security recognized laboratory capacity for radiation biodosimetry as having a significant gap for performing mass radiation dose assessment. The anticipated demand for radiation biodosimetry exceeds its supply, and this gap is partly linked to the limited number and analytical complexity of laboratory methods for determining radiation doses within patients. The dicentric assay is a key component of a cytogenetic biodosimetry response asset, as it has the necessary sensitivity and specificity for assessing medically significant radiation doses. To address these shortfalls, the authors have developed a multimodal strategy to expand dicentric assay capacity. This strategy includes the development of an internet-based cytogenetics network that would address immediately the labor intensive burden of the dicentric chromosome assay by increasing the number of skilled personnel to conduct the analysis. An additional option that will require more time includes improving surge capabilities by combining resources available within the country's 150 clinical cytogenetics laboratories. Key to this intermediate term effort is the fact that geneticists and technicians may be experts in matters related to identifying chromosomal abnormalities related to genetic disorders, but they are not familiar with dosimetry for which training and retraining will be required. Finally, long-term options are presented to improve capacity focus on ways to automate parts of the dicentric chromosome assay method.
• Health physics.Health Phys.2014 Apr;106(4):516-22. doi: 10.1097/HP.0b013e3182a5f94f.
• In the moments immediately following a nuclear detonation, casualties with a variety of injuries including trauma, burns, radiation exposure, and combined injuries would require immediate assistance. Accurate and timely radiation dose assessments, based on patient history and laboratory testing, are
• PMID 24562072

• Radiation safety considerations for the use of ²²³RaCl₂ DE in men with castration-resistant prostate cancer.

• Dauer LT1, Williamson MJ, Humm J, O'Donoghue J, Ghani R, Awadallah R, Carrasquillo J, Pandit-Taskar N, Aksnes AK, Biggin C, Reinton V, Morris M, St Germain J.Author information 1*Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY; †Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY; ‡Department of Radiology, Weill Cornell Medical College, New York, NY; §Algeta ASA, Oslo, Norway; **Genitourinary Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; ††Department of Medicine, Weill Cornell Medical College, New York, NY.AbstractThe majority of patients with late stage castration-resistant prostate cancer (CRPC) develop bone metastases that often result in significant bone pain. Therapeutic palliation strategies can delay or prevent skeletal complications and may prolong survival. An alpha-particle based therapy, radium-223 dichloride (²²³RaCl₂), has been developed that delivers highly localized effects in target areas and likely reduces toxicity to adjacent healthy tissue, particularly bone marrow. Radiation safety aspects were evaluated for a single comprehensive cancer center clinical phase 1, open-label, single ascending-dose study for three cohorts at 50, 100, or 200 kBq kg⁻¹ body weight. Ten patients received administrations, and six patients completed the study with 1 y follow-up. Dose rates from patients administered ²²³Ra dichloride were typically less than 2 μSv h⁻¹ MBq⁻¹ on contact and averaged 0.02 μSv h⁻¹ MBq⁻¹ at 1 m immediately following administration. Removal was primarily by fecal excretion, and whole body effective half-lives were highly dependent upon fecal compartment transfer, ranging from 2.5-11.4 d. Radium-223 is safe and straightforward to administer using conventional nuclear medicine equipment. For this clinical study, few radiation protection limitations were recommended post-therapy based on facility evaluations. Specific precautions are dependent on local regulatory authority guidance. Subsequent studies have demonstrated significantly improved overall survival and very low toxicity, suggesting that ²²³Ra may provide a new standard of care for patients with CRPC and bone metastases.
• Health physics.Health Phys.2014 Apr;106(4):494-504. doi: 10.1097/HP.0b013e3182a82b37.
• The majority of patients with late stage castration-resistant prostate cancer (CRPC) develop bone metastases that often result in significant bone pain. Therapeutic palliation strategies can delay or prevent skeletal complications and may prolong survival. An alpha-particle based therapy, radium-223
• PMID 24562070

• Study of the counting efficiency of a WBC setup by using a computational 3D human body library in sitting position based on polygonal mesh surfaces.

• Fonseca TC1, Bogaerts R, Lebacq AL, Mihailescu CL, Vanhavere F.Author information 1*Belgian Nuclear Research Centre-SCK-CEN, Boeretang, 200 Mol, 2400, Belgium; †University Hospital Gasthuisberg, Department of Radiation Oncology, Herestraat 49, B-3000, Leuven, Belgium.AbstractA realistic computational 3D human body library, called MaMP and FeMP (Male and Female Mesh Phantoms), based on polygonal mesh surface geometry, has been created to be used for numerical calibration of the whole body counter (WBC) system of the nuclear power plant (NPP) in Doel, Belgium. The main objective was to create flexible computational models varying in gender, body height, and mass for studying the morphology-induced variation of the detector counting efficiency (CE) and reducing the measurement uncertainties. First, the counting room and an HPGe detector were modeled using MCNPX (Monte Carlo radiation transport code). The validation of the model was carried out for different sample-detector geometries with point sources and a physical phantom. Second, CE values were calculated for a total of 36 different mesh phantoms in a seated position using the validated Monte Carlo model. This paper reports on the validation process of the in vivo whole body system and the CE calculated for different body heights and weights. The results reveal that the CE is strongly dependent on the individual body shape, size, and gender and may vary by a factor of 1.5 to 3 depending on the morphology aspects of the individual to be measured.
• Health physics.Health Phys.2014 Apr;106(4):484-93. doi: 10.1097/HP.0b013e3182a414ba.
• A realistic computational 3D human body library, called MaMP and FeMP (Male and Female Mesh Phantoms), based on polygonal mesh surface geometry, has been created to be used for numerical calibration of the whole body counter (WBC) system of the nuclear power plant (NPP) in Doel, Belgium. The main ob
• PMID 24562069

Japanese Journal

• Determination of Pseudo Multi-Pulse Production Rate in GM Counters by Correlation Analysis between Signal Pulses

• ,
• Journal of nuclear science and technology 33(1), p.83-86, 1996-01-25
• … A technique, based on the correlation analysis of signal pulses in time sequence, is proposed to determine the production rate of the pseudo multi-pulse in Geiger-Mueller (GM) counter. … These results indicate that the consumption of the quench gas results in a significant increase in the production rate but little variation in the lag time, and that the lag time strongly depends on the tube diameter. …
• NAID 10002074092

• THE NUMBER OF COUNTS OF BETA-RAYS DETECTED BY AN END WINDOW GEIGER-MUELLER COUNTER PART II

• Mineralogical Journal 1(5), 303-312, 1955
• … ndow Geiger-Mueller counter at a distance more than four centimetres have been calculated with the results as follows: T=60πpNW/C*G, where G=e-μ*AH/[cosδ]g, g=(tan-1H2+x12/XH-tan-1H/X)XH/4, or g=(1/H2-1/H2+X12)S0H4, and μ*A: the absorption coefficient for air regarding the number of betarays (cm-1), [cos δ]: the mean velue of cos δ, S0: the effective solid angle at the point in which the extension of the central line of Geiger-Mueller tube …
• NAID 130004005252

• X線計數分光器の研究 (第I報)

• 篠田 軍治,戸村 光一
• X線 6(2), 45-51, 1950
• … 5 and 6, if we intend to reduce the errors as low as 5%, the speed of rotation of a counter-tube must be reduced to nearly half of the constant<I>RC</I>type, i.e. 3.6 degree/min. and 6 degree/min. respectively. …
• NAID 130001996465

Related Links

• Geiger–Müller tubeとは - goo Wikipedia (ウィキペディア)

The Geiger–Müller tube (or G-M tube) is the sensing element of the Geiger counter instrument used for the detection of ionizing radiation. It was named after Hans Geiger, who invented the principle in 1908, [1] and Walther Müller, who ...

• The Geiger-Müller tube | Nuffield Foundation

Demonstration This is a general introduction to the Geiger-Müller (G-M) tube describing and explaining the basic principles of its operation. Apparatus and materials Scaler Holder for GM tube Thin window GM tube Gamma source, as ...

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リンク元	「Geiger-Mueller counter」
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「Geiger-Mueller counter」

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• ガイガーミュラー計数管、Geiger-Mueller計数管

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Geiger-Mueller tube、radiometry

「tube」

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• n.

• 管、チューブ

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canal、duct、ductal、ductus、meatus、pipe、tubal、vas

　 　 　 　 　 　 　 　

「Mueller」

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ミュラー、ミューラー

関

Muller