Forest SolidState Detectors
Solid state detectors are basically materials in which a radiation sensitive region of mobile carriers is established with a voltage. A gas chamber in solid form.
What is a semi-conductor
- Valence band
- electrons tightly bound to the crystal's atoms occupy this energy band
- Conduction band
- electrons detached from the parent atom occupy this energy band and are free to roam about the crystal
- Energy gap
- the Energy gap is the represents the amount of energy needed for an electron to move from the valence band to the conduction band
Conductors
In a conductor, there is no band gap. The valence and conduction bands overlap. Electrons are free to move according to the applied voltage.
Insulators
Insulators have energy gaps of about 6 eV at room temperature.. All of the electrons are in the Valence band. If you heat up the insulator though you could start to get a leakage current with a high enough voltage.
Semi-Conductors
The energy gap in a semi-conductor is about 1 eV at room temperature. This gap is so small that valence electrons could enter the conductive band due to their thermal excitation.
The energy gap is about 1 eV for a semi-conductor and about 6 eV for an Insulator. In a Conductor, there is no energy gap. The Valence and Conduction bands overlap.
Silcon is the most commonly used material for such detectors. Germanium, Gallium-Arsenide, and diamond are also used.
A min ionizing particle liberates about 300 fC (22000 electrons) in a 300 m thick piece of silicon.