Pyroelectric IR Detectors

Single element pyroelectric DLATGS infrared detectors have been manufactured by SELEX Galileo for over 40 years. Tri-Glycene Sulphate (TGS) is one of the best pyroelectric materials to use as a thermal detector and offers a high signal to noise capability. Deuteration increases the Curie temperature to 60OC, Alanine doping enables it to repole should it be exposed to temperatures above its Curie point.

Initially this technology was utilised by the military market, but is now largely favoured for instruments in scientific, industrial and Space markets where a low cost radiation detector is required. The major application is in infrared spectrometry and microscopy used for material identification and analysis. The spectral capability of DLATGS extends from the X-ray region through the infrared to microwaves to the THz spectral region.

SELEX Galileo grow their own DLATGS material as a single crystal. The process for doping Triglycene Sulphate (TGS) to form DLATGS crystals was developed and patented by the Company in the early 1970s. Samples of new material are processed and measured to ensure it has acceptable ferroelectric and pyroelectric characteristics for build into detectors. These characteristics include dielectric constant, loss tangent and degree of Alanine doping. Suitable material is allocated for production build.

SELEX Galileo design detectors into industry standard packages - 'TO5', 'TO66' and 'TO37' configurations.
 
A variety of detector configurations are available covering a range of pyroelectric element shapes, dimensions, transmitting windows, hermeticity and pinning. All of these can be adapted to suit Customer requirements. In the case of the TO66 and TO37 packages these will include a single stage peltier cooler (TEC) to enable temperature stabilisation of the pyroelectric element under conditions where the ambient temperature may be changeable. The Company can also offer a design capability for non-standard product and packages including linear and 2D arrays.
 
Detector configuration and electro-optic performance expected under defined test conditions is described on the each product's specific datasheet supplied to the Customer.

SELEX Galileo is a high volume manufacturer of detectors using a range of proprietary processes developed specifically to optimise DLATGS detector performance for both spectral and modulation frequency characteristics. The pyroelectric element mounting process is chosen to optimise signal to noise for the modulation frequency range of interest to the Customer. Should the Customer application involve exposure of the element to very high radiant power levels, as may be expected in some laser applications, the mounting process will be further optimised to protect the mechanical integrity of the element. Minimising exposure to moisture is achieved by appropriate engineering of the detector package, including bonding of the softer materials used as infrared transmitting windows as well as full hermetic sealing of harder materials.

Each detector is tested under standard conditions to ensure its electro-optic performance meets the requirements for its type. The measurements are for signal and noise from which the characteristic responsivity and D* (specific detectivity) are derived. Signal measurements use a black body source at a temperature of either 500K or 1000K with the radiation modulated using a mechanical chopper at representative frequencies. Noise is measured with a suitable spectrum analyser. All detectors are measured with the pyroelectric element at an ambient temperature of 21±2OC. Each detector is supplied with a test certificate detailing the performance under these standard conditions.
 
Further information can be found under our IR Detector products page, or contact infrared.sales@selexgalileo.com.
 
Pyrolelectric Detector Brochure.pdf (876 KB)
Wren Detector Brochure.pdf (199 KB)