Forest IonizationChambers - Revision history

Oborn: /* Proportional */

2008-06-09T18:50:32Z

Proportional

2008-06-09T18:43:43Z

Proportional

2008-06-09T18:43:06Z

Proportional

2008-06-09T18:36:00Z

Geiger Muller

2008-06-09T18:35:50Z

Geiger Muller

2008-06-09T18:34:42Z

Geiger Muller

2008-06-09T18:33:17Z

Geiger Muller

2008-06-09T18:28:42Z

Geiger Muller

2008-06-09T18:27:05Z

2008-06-09T18:25:55Z

@@ Line 39: / Line 39: @@
 At some point(Limited proportionality region)  though you start to create enough positive ions that the electric field strength decreases and you get less avalanche even though you are increasing the voltage.
-In this region the number of liberated electrons grows as they are swept to the anode such that
+In this region the number of liberated electrons grows exponentially as they are swept to the anode such that
 :<math>N = N_0 e^{\alpha x}</math>
@@ Line 46: / Line 46: @@
 : <math>\alpha =</math> first Townsend coefficent
 :<math>x =</math> distance from original ionization event and the anode
 = Geiger Muller=

@@ Line 44: / Line 44: @@
 where
-: <math>\alpha =</math> Townsend coefficent
+: <math>\alpha =</math> first Townsend coefficent
 :<math>x =</math> distance from original ionization event and the anode

← Older revision		Revision as of 18:43, 9 June 2008
Line 39:		Line 39:
	At some point(Limited proportionality region) though you start to create enough positive ions that the electric field strength decreases and you get less avalanche even though you are increasing the voltage.		At some point(Limited proportionality region) though you start to create enough positive ions that the electric field strength decreases and you get less avalanche even though you are increasing the voltage.

		+	In this region the number of liberated electrons grows as they are swept to the anode such that

		+	:<math>N = N_0 e^{\alpha x}</math>
		+
		+	where
		+	: <math>\alpha =</math> Townsend coefficent
		+	:<math>x =</math> distance from original ionization event and the anode

	= Geiger Muller=		= Geiger Muller=

@@ Line 53: / Line 53: @@
 A view for the Geiger Muller operating region.  The signal plateaus.
 [[Image:GM_Plateau.jpg]]
 [http://www.iac.isu.edu/mediawiki/index.php/Forest_Detectors Go Back]

@@ Line 51: / Line 51: @@
 [[Image:Forest_IoniztionChamberOperatingRegions.jpg]]
 [[Image:GM_Plateau.jpg]]
 [http://www.iac.isu.edu/mediawiki/index.php/Forest_Detectors Go Back]

@@ Line 43: / Line 43: @@
 = Geiger Muller=
-At some point the high voltage is high enough that the number of positive ion pairs saturates (you don't create any more even though the voltage is increased).  This is called the Geiger Muller plateau.  If you go too high in voltage you will start to have electrostatic discharge making the device give a signal without having any ionizing radiation.
+At some point the high voltage is high enough that the number of positive ion pairs saturates (you don't create any more even though the voltage is increased).  This is called the Geiger Muller plateau.  In the Geiger Muller region the signal is independent of the ionizing particle since the signal is already at its maximum.
 [[Image:Forest_IonizationChambers_Electron-IonPairFormation.png]]

@@ Line 1: / Line 1: @@
 An ionization chamber is essentially a gas filled volume which has one or more wires suspended inside with a voltage bias used to collect any ions or liberated electrons within the volume.
 There are 4 basic operating regions which are determined by the amount of the voltage across the wire(s).
@@ Line 42: / Line 44: @@
 At some point the high voltage is high enough that the number of positive ion pairs saturates (you don't create any more even though the voltage is increased).  This is called the Geiger Muller plateau.
 [[Image:GM_Plateau.jpg]]