How does a germanium detector work?

Ionizing radiation enters the sensitive volume (germanium crystal) of the detector and interacts with the semiconductor material. High-energy photon passing through the detector ionizes the atoms of semiconductor, producing the electron-hole pairs.

How does a gamma detector work?

Like X-ray detection, gamma-ray detection is done photon-by-photon. Gamma rays are detected by observing the effects they have on matter. A gamma ray can collide with an electron and bounce off it like a billiard ball (Compton scatter) or it can push an electron to a higher energy level (photoelectric ionization).

How do gamma rays interact with a GM detector?

When gamma rays interact in scintillator material, ionized (excited) atoms in the scintillator material “relax” to a lower-energy state and emit photons of light. In a pure inorganic scintillator crystal, the return of the atom to lower-energy states with the emission of a photon is an inefficient process.

What are germanium detectors used for?

Since germanium detectors produce the highest resolution commonly available today, they are used to measure radiation in a variety of applications including personnel and environmental monitoring for radioactive contamination, medical applications, radiometric assay, nuclear security and nuclear plant safety.

How does a high purity germanium detector work?

HPGe Detector – Principle of Operation Ionizing radiation enters the sensitive volume (germanium crystal) of the detector and interacts with the semiconductor material. High-energy photon passing through the detector ionizes the atoms of semiconductor, producing the electron-hole pairs.

What is SSD detector?

Solid-state semiconductor detectors are radiation detectors which employs a semiconductor material as the detecting medium. These detectors produce pulse of electric current by means of pairs of charge carriers, electrons and holes, generated when the detectors come in contact with ionizing radiation.

What devices detect gamma rays?

The Geiger-Mueller (GM) detector is a common portable instrument choice for a general laboratory radioactive material survey. GM detectors are capable of detecting alpha, beta, and gamma radiation.

Which detector is suitable for determining gamma rays?

The thallium-activated sodium iodide detector, or NaI(Tl) detector, responds to the gamma ray by producing a small flash of light, or a scintillation. The scintillation occurs when scintillator electrons, excited by the energy of the photon, return to their ground state.

What is a high purity germanium detector?

Synopsis: High Purity Germanium (HPGe) is the only radiation detection technology that provides sufficient information to accurately and reliably identify radionuclides from their passive gamma ray emissions. HPGe detectors have a 20-30x improvement in resolution as compared to that of Sodium Iodide (NaI) detectors.

What causes the Compton edge?

Compton edge. They are produced when the angle of the scattered gamma ray is 180 degrees. Photons scattered at 180 degrees frequently have energies close to 200 keV. As such, the Compton edge is usually 200 keV to the left of the photopeak.

Why are Si and Ge used in making solid state detectors?

The advantages of germanium over silicon for this application are improved signal to noise ratio and energy resolution and the capability of detecting photons up to 100 keV with reasonable efficiency even with small volume devices.

Germanium detectors are semiconductor diodes having a P-I-N structure in which the Intrinsic (I) region is sensitive to ionizing radiation, particularly X rays and gamma rays. Under reverse bias, an electric field extends across the intrinsic or depleted region.

What can we learn from the measurement of gamma rays?

Measurement of gamma rays let us deduce: Energy, Spin (angular distr./correl.), Parity (polarization), magnetic moment, lifetime (recoil distance Doppler-shift), …. of the involved nuclear levels. A partial level scheme of 75Kr… …as an example for the richness of gamma-ray spectroscopic informat ion.

What are scintillators in gamma rays?

Structure of a gamma-ray spectrum [KNO] Scintillator Scintillators are materials that produce ‘small flashes of light’ when struck by ionizing radiation (e.g. particle, gamma, neutron). This process is called ‘ Scintillation ’. Scintillators may appear as solids, liquids, or gases.

What are the requirements of a good electron-hole pair detector?

Purity of a detector material is of the highest importance. The electron-hole pair collection within the detector must be done within a reasonably short time. Moreover there must be no traps which can prevent them reaching the collecting contacts. Trapping centres can be due to: