Golay cell
A Golay cell is a pneumatic radiation detector (hence also called a Golay detector ), which was first developed by Marcel JE Golay around 1947 . It can be operated at room temperature and typically covers a wavelength range from 1 micrometer to a few millimeters. This makes it ideal for use as a detector for terahertz radiation .
functionality
The incident radiation enters the cell through a window (e.g. made of diamond or PE-HD ) and is absorbed there by a thin, partially transparent film . The cell is filled with a gas to which the foil releases the absorbed energy , whereby it heats up. The gas expands a little and the pressure in the cell increases. The back of the cell is closed with an elastic membrane that deforms as a result of the increase in pressure. This deformation is visually detected in Golay cells, e.g. B. with the light of a light emitting diode , which is reflected by the membrane . This is achieved with specially designed optics that first focus the light beam on the membrane and, after reflection, directs it onto a photodiode . The intensity registered by the photodiode is functionally dependent on the expansion of the membrane.
Golay cells can (as well as pyroelectric detectors ) detect terahertz radiation . B. over bolometers the advantage that they can be operated at room temperature, so without cooling. The measurable wavelength range is only determined by the absorption behavior of the film in the measuring cell. The sensitivity of a Golay cell can e.g. B. can be increased by using a laser as a light source in the optical part and interferometrically detecting the membrane movement .
Individual evidence
- ↑ Marcel JE Golay: Theoretical Consideration in Heat and Infra-Red Detection, with Particular Reference to the Pneumatic Detector . In: Review of Scientific Instruments . tape 18 , no. 5 , 1947, pp. 347-356 , doi : 10.1063 / 1.1740948 .
