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Why must a Geiger Muller tube for detecting alpha particles have very high thin end window?
A GM (Geiger-Muller) tube for detecting alpha particles must have a very thin window because alpha particles are highly interactive, and they can be stopped with very little, such as only a few inches of air, a sheet of paper, your skin, etc. Typical GM detectors for alpha application use mylar as the window. Even so, the mylar does interfere with the alpha detection, but this is better than nothing.
Does a geiger tube count all radiation?
No. A GM tube only counts the ionizing events that happen to interact with it. Consider that a radioactive source radiates in 360 degrees, in three axes, to form a three dimensional sphere of radiation. The GM tube intersects only part of that sphere and, even for the the parts that do intersect, its not always a direct intersection, so there is not always a capture of an event that registers on the tube. This is why we talk about calibration geometry and efficiency.
Why inert gases are used in gm tube?
Inert gases, such as argon or neon, are used in Geiger-Muller (GM) tubes because they are chemically stable and do not easily react with other elements. This ensures a consistent environment inside the tube for detecting ionizing radiation without interference from chemical reactions. Additionally, inert gases help to facilitate the ionization process that occurs when radiation interacts with the gas inside the tube.
What does the term count rate mean when using a geiger counter?
A geiger counter measures ionizing radiation - alpha, beta and gamma (though gamma is indirect). The detector within a geiger counter is a Geiger Muller tube, it is basically a metallic gas-filled chamber with a thin wire anode running axially in the center of the tube and a cathode, the tube wall. The gas is most commonly an inert gas like the noble gases (like argon, neon). The anode is set to a very high charge compared to the tube wall. Also one end of the tube is typically has a thin mica wall or a thin glass wall to allow beta or alpha particles in. Once an alpha or beta particle enters the tube they can collide with the gas atoms forming an electron and postively charge ion. The electron speeds off to the positively charged anode while the ion accelerates to the cathode. Along the way the electron or ion can collide into other gas atoms creating more free electrons and ions and they in turn can knock other gas atoms creating an avalanche effect. The surge of electrons on the anode causes a current pulse that can be measured as a hit by a counter. In the presence of radiation sources the geiger counter's hits per second will increase significantly. As a side note gamma radiation first has to knock an electron from the side wall and it is this electron that causes the cascade.
What is the dead time of gm tube?
when the beta particle from a decay product enters the geiger muller tube, it collides with an atom ionizing it which in turn releases more electrons. this causes a chain reaction of cascading electrons until it hits the electrode which is measured as one count. After this event, the tube is filled with slow moving positive ions that advance towards the outer walls. during this time, an electron(beta particle) that enters the tube will strike an electron and become absorbed by these positive ions instead of causing another avalanche. This is the dead time.
If 600 counts are produced in one minute through a Geiger muller tube why have the counts decreased to 500 in a minute over a year?
Because the rate of the radioactive decomposition reaction has decreased.
What are some medical uses of radiation?
to detect radiation, a device such as Geiger- Muller tube is used
When radiation travels through the window of the geiger muller tube what happens so that the tube sends a signal that it has detected a particle?
When radiation enters the Geiger-Muller tube, it ionizes the gas inside. This ionization creates a conductive path that allows current to flow in the tube, triggering a voltage pulse that is counted as a particle detection event.
Instrument for detecting radioactivity?
A device generically called a Radiac, however there are dozens of different kinds of Radiacs which operate by different principles and measure different things. Some are:geiger-mueller counterrate meterionization chamber meterscintillation counterelectrometer dosimeterionization chamber dosimeterphotographic film dosimeter
Why should argon be at low pressure in the geiger muller tube?
Argon is used in the Geiger-Muller tube as a quenching gas to stop the discharge of ions after each pulse. Keeping argon at low pressure allows for efficient quenching of the ionization process. Higher pressure could interfere with the detection process by preventing the resetting of the tube after each detection event.
What is pulse current?
pulse of current is produced at every burst of radiation ending geiger muller tube. when this radiation hits the argon atoms; present in the tube electrons are knocked off.
What characteristic of radiation allows a Geiger counter to measure radiation levels?
A Geiger counter measures radiation levels by detecting ionizing radiation. When radiation interacts with the gas inside the Geiger-Muller tube, it causes the gas to ionize and create an electrical pulse that is counted by the device.
What is Geiger Muller scintillation?
Simply put, the Geiger-Müller (GM) detector or tube is the "business end" of a Geiger counter. It's the tube that the ionizing radiation "goes into" where it interacts with the gas inside to allow detection of the "count" or "pulse" of ionizing radiation. Use the links below to related articles and questions. The related questions in particular might be of value.
Why do we use a Geiger-Mueller tube?
A geiger-mueller tube is used in the detection of ionizing radiation.
How do you use the geiger muller tube to test for alpha?
Do you want to verify that a radioactive source emits ONLY alpha particles? If so, first measure the original count-rate, with no radioactive source, on the GM-tube. This is the background count-rate. Next, place the radioactive source near the GM-tube, and measure the new count-rate. Place a thin piece of paper between the GM-tube and the source. You will see that the count-rate dropped to the background count-rate. This is because all of the alpha particles are absorbed by the paper. If there were other types of radiation, like beta and gamma radiation, the count-rate wouldn't drop to the background count-rate.
Why must a Geiger Muller tube for detecting alpha particles have very high thin end window?
A GM (Geiger-Muller) tube for detecting alpha particles must have a very thin window because alpha particles are highly interactive, and they can be stopped with very little, such as only a few inches of air, a sheet of paper, your skin, etc. Typical GM detectors for alpha application use mylar as the window. Even so, the mylar does interfere with the alpha detection, but this is better than nothing.
What is quenching in Geiger muller tube?
A small amount of vapours of a substance having low ionization potential, called as quenching gas, eg alcohol vapours, is added to gm tube, which discharges at cathode before the principle gas +ve ions which discharges at cathode in about 10^-4 seconds. So the quenching gas neutralizes itself and also the tube....
