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detectors [2013/12/13 19:08] pereira [Ionization Chamber] |
detectors [2013/12/13 19:10] pereira [Ionization Chamber] |
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| The principle of operation of the ionization chamber is illustrated in the right figure below. The electrons and positive ions liberated by the ionization of the gas along the particle trajectory drift towards the closest anode-cathode pair. The drifting electrons and ions absorb the energy stored in the detector capacity and produce a voltage change of the anodes across the resistor. The main advantages of the anode-cathode configuration is that the electrons and ions are collected on a very short distance (about 1.5 cm), thus reducing pile-up and position dependence of the signals. Moreover, dividing the detector into 16 sections reduces the detector capacitance and consequently its noise. The operating voltage depends on the charge of the measured nuclei (e.g. __xxx for xxx and xxx for xxx__). Each anode is attached to a small preamplifier inside the ion chamber. This significantly reduces the electronic noise, although it involves the venting of the whole chamber whenever a malfunctioning preamplifier needs to be replaced. The electronic signals from the preamplifier are sent into a [[https://groups.nscl.msu.edu/nscl_library/manuals/caen/MOD.N568B.pdf|CAEN N568B]] 16-channel shaper/amplifier with remotely adjustable gains. The output signals feed a [[https://groups.nscl.msu.edu/nscl_library/manuals/phillips/7164H.pdf|Phillips 7164H]] ADC. |
| The energy-loss resolution of the ionization chamber can be significantly improved after correcting the position and momentum dependences. Elements up to Z=50 can be separated. |
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{{:wiki:ion-chamber-picture.jpg?550 |Picture of the S800 ionization chamber with its alternating cathode and anode plates.}} | |
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{{ :wiki:ion-chamber-drawing.jpg?550|Schematic representation of the principle of operation of the ionization chamber.}} | |
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| {{:wiki:ion-chamber-picture.jpg?500 |Picture of the S800 ionization chamber with its alternating cathode and anode plates.}} |
| {{ :wiki:ion-chamber-drawing.jpg?500|Schematic representation of the principle of operation of the ionization chamber.}} |
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The principle of operation of the ionization chamber is illustrated in the right figure above. The electrons and positive ions liberated by the ionization of the gas along the particle trajectory drift towards the closest anode-cathode pair. The drifting electrons and ions absorb the energy stored in the detector capacity and produce a voltage change of the anodes across the resistor. The main advantages of the anode-cathode configuration is that the electrons and ions are collected on a very short distance (about 1.5 cm), thus reducing pile-up and position dependence of the signals. Moreover, dividing the detector into 16 sections reduces the detector capacitance and consequently its noise. The operating voltage depends on the charge of the measured nuclei (e.g. __xxx for xxx and xxx for xxx__). Each anode is attached to a small preamplifier inside the ion chamber. This significantly reduces the electronic noise, although it involves the venting of the whole chamber whenever a malfunctioning preamplifier needs to be replaced. The electronic signals from the preamplifier are sent into a [[https://groups.nscl.msu.edu/nscl_library/manuals/caen/MOD.N568B.pdf|CAEN N568B]] 16-channel shaper/amplifier with remotely adjustable gains. The output signals feed a [[https://groups.nscl.msu.edu/nscl_library/manuals/phillips/7164H.pdf|Phillips 7164H]] ADC. | |
The energy-loss resolution of the ionization chamber can be significantly improved after correcting the position and momentum dependences. Elements up to Z=50 can be separated. | |
===== Hodoscope ===== | ===== Hodoscope ===== |
A Cs(Na) hodoscope detector located downstream of the [[Detectors#Plastic scintillators|E1 scintillator]] is used to measure the total kinetic energy of implanted nuclei, allowing the identification of different charge states. An additional use recently tested is the measurement of isomer gamma-rays emitted from implanted nuclei. | A Cs(Na) hodoscope detector located downstream of the [[Detectors#Plastic scintillators|E1 scintillator]] is used to measure the total kinetic energy of implanted nuclei, allowing the identification of different charge states. An additional use recently tested is the measurement of isomer gamma-rays emitted from implanted nuclei. |