Hodoscope
Encyclopedia
A hodoscope is a type of detector used in particle physics
which makes use of coincident detections to determine the trajectory of an energetic particle. Typically, a hodoscope consists of an array of sub-detectors which can each independently detect a particle passing through it. As a particle passes through the hodoscope, its trajectory will pass through multiple sub-detectors. Based on the combination of sub-detectors that are hit, the particle's trajectory can be inferred.
The sub-detector elements in a hodoscope are typically paddles of scintillating
plastic. As a particle passes through the paddle, it will ionize atoms in the plastic, causing scintillation light. This light can then be measured with a photomultiplier
tube (PMT). Since the light collection and readout from the PMT is quite quick, scintillating hodoscopes are useful as a trigger
or to gather timing information for an experiment.
There are many possible geometric arrangements of detectors in a hodoscope. One common approach is to have two parallel planes, each made up of scintillating strips. In the first plane, the strips might be arranged vertically, while arranged horizontally in the second. If a particle crosses the detector, it will hit one vertical strip, and one horizontal strip, localizing its trajectory.
Particle physics
Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
which makes use of coincident detections to determine the trajectory of an energetic particle. Typically, a hodoscope consists of an array of sub-detectors which can each independently detect a particle passing through it. As a particle passes through the hodoscope, its trajectory will pass through multiple sub-detectors. Based on the combination of sub-detectors that are hit, the particle's trajectory can be inferred.
The sub-detector elements in a hodoscope are typically paddles of scintillating
Scintillator
A scintillator is a special material, which exhibits scintillation—the property of luminescence when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate, i.e., reemit the absorbed energy in the form of light...
plastic. As a particle passes through the paddle, it will ionize atoms in the plastic, causing scintillation light. This light can then be measured with a photomultiplier
Photomultiplier
Photomultiplier tubes , members of the class of vacuum tubes, and more specifically phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum...
tube (PMT). Since the light collection and readout from the PMT is quite quick, scintillating hodoscopes are useful as a trigger
Trigger (particle physics)
In particle physics, a trigger is a system that uses simple criteria to rapidly decide which events in a particle detector to keep when only a small fraction of the total can be recorded. Trigger systems are necessary due to real-world limitations in data storage capacity and rates...
or to gather timing information for an experiment.
There are many possible geometric arrangements of detectors in a hodoscope. One common approach is to have two parallel planes, each made up of scintillating strips. In the first plane, the strips might be arranged vertically, while arranged horizontally in the second. If a particle crosses the detector, it will hit one vertical strip, and one horizontal strip, localizing its trajectory.