Underlying principal of infrared spectroscopy is based upon the molecular vibration which is further composed of the stretching and the bending vibration of a molecule. In order to cover this broad spectrum of wavelengths, a variety of infrared detectors have been developed and produced. IR field.Observing a history of the development of the IR detector technology, a simple theorem, after Norton [9], can be stated: All physical phenomena in the range of about 0.1–1 eV can be proposed for IR detectors.Among these effects are: thermo-electric power (thermocouples), change in elec-trical conductivity (bolometers), gas expansion 38 Spectroscopy Thermal Detectors A thermal detector absorbs radiation and changes tem-perature. 3. These detectors use the photoelectric effect, in which incident photons free electrons from the surface of the detector material. PMTs can detect IR, visible, and UV light, and can be very sensitive and have very fast response times. 2 Introduction Infrared radiation consists of electromagnetic waves in the wavelength region from 0.75 µm to 1000 µm, lying between visible light and microwave light. The mid-infrared, approximately 4000-400 cm-1 (30–1.4 μm) may be used to study the fundamental vibrations and associated rotational-vibrational structure. detectors, focusing primarily on Fourier transform infrared (FT-IR). Principal. 4. devices from IR detector materials generally unsuccessful – Silicon technology is very mature (1000s of MY experience) • Solution is to separate photodetection and readout technologies • Hybrid array: IR detector, Si readout makes use of best of each technology • Detector and readout can be separately tested (improve yield) – Imaging and spectroscopy examples . PMTs respond best when used to detect radiation in the UV and visible regions, but they are used as detectors in a wide variety of instruments, from gamma and X-ray spectrometers to near IR spectrometers. The higher energy near-IR, approximately 14000-4000 cm-1 (1.4–0.8 μm) can excite overtone or harmonic vibrations. Some are cooledto minimize darkcurrent.Many areso sensitive that they can be burned out if the incoming light is too bright. No comments. Portable Fourier transform infrared spectroscopy chemical detectors (FTIR) are widely used by first responders to identify unknown or suspect materials. It will help guide your choice of the ideal detector for your application. The Near infrared Region : This is also known as vibration region and ranges from 2.5 to 25 mu. for rotational spectroscopy. 19 July 2010 NOAO Gemini Data Workshop 3 Define infrared by detectors/atmosphere • “visible”: 0.3 – 1.0 µm; CCDs • Near-IR: 1.0 – 5.2 µm; InSb, H 2O absorption • Mid-IR : 8 – 25 µm; Si:As, H 2O absorption • Far-IR: 25 – 1000 µm; airborne, space vis near-ir mid-ir far-ir Eric Becklin, SOFIA . The far Infrared region : This is know as the rotation region.This ranges from 25 to 300 – 400mu. Absorption of infrared radiation brings about changes in molecular vibrations so in studying infrared spectroscopy we are looking at the ways in which bonds in molecules vibrate (see video in the previous section). This is possible through the use of a variety of scintillators, discussed above, placed between the incoming photons and the photocathode. Applications include chemical spills, suspicious substance/package screening, clandestine labs, illegal dumping sites, arson investigations, and unlabeled containers or drums. Applications include chemical spills, suspicious substance/package screening, clandestine labs, illegal dumping sites, arson investigations, and unlabeled containers or drums.