Why detect gamma rays

Since gamma rays cannot be focused by conventional telescope techniques, i. Gamma-ray photons have so much energy that they like to pass right through most materials without interacting with them -- so you wouldn't even know that the gamma ray had been there! How, then, do we 'detect' gamma rays? The first class would typically be called spectrometers or photometers in optical astronomy. These detectors are essentially "light buckets" that focus on a region of the sky containing the object of interest collecting as many photons as possible.

These types of detectors generally use scintillators or solid-state detectors to transform the gamma-ray into optical or electronic signals that are recorded. The voltage of detector is adjusted so that the conditions correspond to the Geiger-Mueller region. The high amplification factor of the Geiger counter is the major advantage over the ionization chamber.

Geiger counter is therefore a much more sensitive device than other chambers. It is often used in the detection of low-level gamma rays and beta particles for this reason.

Scintillation counters are used to measure radiation in a variety of applications including hand held radiation survey meters, personnel and environmental monitoring for radioactive contamination , medical imaging, radiometric assay, nuclear security and nuclear plant safety.

They are widely used because they can be made inexpensively yet with good efficiency, and can measure both the intensity and the energy of incident radiation. Scintillation counters can be used to detect alpha , beta , gamma radiation.

They can be used also for detection of neutrons. For these purposes, different scintillators are used. High-purity germanium detectors HPGe detectors are the best solution for precise gamma and x-ray spectroscopy. As was written, the study and analysis of gamma ray spectra for scientific and technical use is called gamma spectroscopy, and gamma ray spectrometers are the instruments which observe and collect such data.

A gamma ray spectrometer GRS is a sophisticated device for measuring the energy distribution of gamma radiation. For the measurement of gamma rays above several hundred keV, there are two detector categories of major importance, inorganic scintillators as NaI Tl and semiconductor detectors. If a perfect energy resolution is required, we have to use germanium-based detector , such as the HPGe detector.

Germanium-based semiconductor detectors are most commonly used where a very good energy resolution is required, especially for gamma spectroscopy , as well as x-ray spectroscopy. In gamma spectroscopy, germanium is preferred due to its atomic number being much higher than silicon and which increases the probability of gamma ray interaction. Moreover, germanium has lower average energy necessary to create an electron-hole pair, which is 3.

This also provides the latter a better resolution in energy. The FWHM full width at half maximum for germanium detectors is a function of energy. For a 1. If so, give us a like in the sidebar. Detecting gamma rays in locations where they are likely to occur, such as nuclear power stations, is crucial. To detect a gamma ray, first a material needs to be able to stop it. Increasing the density or the thickness of a material or adding the presence of very high atomic weight atoms all increase the chances of stopping these energy waves.

When the gamma ray is stopped by a detector, its high energy means that it can do serious damage, resulting in rapid degradation of the device.

This can make maintaining gamma ray detectors an expensive exercise.