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 [math]\mu[/math] m thick piece of silicon.

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