Semiconductor radiation detectors

Cross-sections through typical semiconductor radiation detectors. The same geometry is used for both intrinsic and semiconductor types. 

Particle-induced X-ray emission (PIXE) is an analytical technique based upon observing fluorescent X-rays. As such, it really is not a nuclear technique since it involves an atomic process, X-ray emission. But the atomic electron shell vacancies that are filled when the X-ray is emitted are created using particle-accelerator beams and one uses typical semiconductor radiation detectors, Si (Li) detectors, to detect the X-rays. 

Ionization in a Solid (Semiconductor Detectors) In a semiconductor radiation detector, incident radiation interacts with the detector material, a semiconductor such as Si or Ge, to create hole-electron pairs. These hole-electron pairs are collected by charged electrodes with the electrons migrating to the positive electrode... 

A silicon-semiconductor-radiation detector of a layer of p-type silicon in contact with a layer of n-type Si is shown in Figure 18.15. What happens when this p-n junction is created The electrons from the n-type silicon will migrate across the junction and fill the holes in the p-type silicon to create an area around the p-n junction in which there is no excess of holes or electrons. (We say that a depletion region has been formed around the junction.) Imagine that we apply a positive voltage to the n-type material and a negative voltage to the p-type material (the junction is said to be reverse biased). The electrons will be pulled farther... 

A micromachined CE device featuring a truly monolithically integrated detector has been recently reported by Webster et al. [79]. A semiconductor radiation detector was fabricated together with a separation channel on a silicon substrate in a 10-mask process. The preliminary results achieved with the detection of beta decay events of 32P-labeled DNA at 27 V/cm demonstrate the feasibility of the concept. 

Semiconductor Radiation Detectors, in Nuclear Spectroscopy and Reactions, Vol. A (Ed. J. 

Indeed, this possibility of obtaining both the radiation frequency (Fig. 2 b) and the intensity (Fig. 4) from a simple electrical resistance measurement suggested the possibility of realizing a simple, tuned, narrowband semiconductor radiation detector, one which operates in the THz regime. 

Marcus CS. 1972. Use of 87mSr and semiconductor radiation detectors for in vivo physiological studies. 

Semiconductor radiation detectors are crystals whose electrical conduction is altered by the absorbed radiation. Their operation depends on their semiconducting properties. They can provide information about type, energy, and intensity of radiation and are the most important devices for radiation spectrometry. 

The personal portable (pocket) dosimeter usually contains a gas-filled or a semiconductor radiation detector (e.g., a G-M tube) tailored with an electronic device and a dedicated... 

X-ray fluorescence (XRF) applications require detectors with ultra-high energy resolution. The primary detectors fulfilling this requirement that are currently available are semiconductor radiation detectors. These devices are often referred to as solid state detectors because their origin lies in the development of materials for transistor technology. They are the detectors of choice for virtually all work in nuclear spectroscopy. 

Goulding F, Stone Y. 1971. Semiconductor radiation detectors in Semiconductor Detectors in the Future of Nuclear Medicine. New York, Society of Nuclear Medicine, Inc., pp. 1-15. 

As mentioned at the beginning of this section, the primary ionization must be collected to make a direct measurement of the energy of nuclear radiation. Condensed phases have higher densities than gases and so provide more efficient stopping of the radiation per unit length. However, metals allow rapid recombination of the elec-tron/positive ion pairs and insulators inhibit the collection of the charge. Therefore, only semiconductors have been used extensively for radiation detectors. Metals and... 

The major components of the system include a krypton gas injector assembly, a radiation detector assembly, detector electronics and a data processor. The heart of the system is the radiotracer detector assembly which uses semiconductor charged particle detectors to measure the relative concn of tracer gas in the ullage. Krypton-85 is considered the safest radioisotope for such use since there is virtually no bodily retention of this gas... 

Fig. 6. Schematic representation of a Ge(Li) semiconductor type radiation detector...

The peak power of infrared radiation at 300 K has a wavelength of 10 microns. This presents the problem that an infrared radiation detector operating in this range will quickly be saturated because many surrounding objects will be at 300 K. The invention of US-A-4807007 refers to metal-insulator-semiconductor, MIS, detectors, each having a potential well of which only a small portion is exposed to infrared radiation. 

Some radiation detectors, i.e., photoemissive detectors (vacuum phototubes or photomultipliers) or semiconductor detectors (photodiodes or phototransistors) directly produce an electrical signal by quantum effects. Their output is strongly dependent on the wavelength of the detected radiation. Thermal detectors, i.e., thermocouples and thermopiles, bolometers, pyroelectric detectors, or pneumatic and photoacoustic detectors record a temperature increase through radiation and convert this into an electrical signal. This is proportional to the flux of the absorbed radiant power, independent of the wavelength. 

P4. Parker, R. P., Semiconductor nuclear radiation detectors. Phys. Med. Biol. 15, 605-620 (1970). 

Diamondlike Carbon and Hard Carbon-Based Sensors Sensors that are based upon diamond technology include thermistors, pressure and flow sensors, radiation detectors, and surface acoustic wave devices [103]. The relative ease of depositing prepattemed, dielectrically isolated insulating and. semiconducting (boron-doped p type) diamond films has made polycrystalline diamond-based sensors low-cost alternatives to those based on conventional semiconductors. Diamondlike carbon and diamond films synthesized by chemical... 

Use Ceramics, infrared radiation detector, semiconductor, ceramic glaze, source of lead. 

Gamma spectroscopy is a radiochemical measurement method that allows identification and quantitative determination of activity of radionuclides, which emit gamma radiation or x-rays. The equipment used in gamma spectroscopy includes an energy-sensitive radiation detector, such as semiconductors, scintillators or proportional counters, and a multichannel analyzer. The energies and the photon yields are characteristic for specific nuclides. 

Below 1.2 K, the cryostats using natural He are replaced by 3He/4He dilution refrigerators. Such refrigerators are commonly used to cool the bolometer/radiation detectors in the mK range (typically 30-60mK range). They are used, for instance, in the detection of the weakly interacting massive particles (WIMP). They have only been used in a limited number of cases for optical studies of impurities in semiconductors [36]. 

Chapters 5-7 describe the different types of radiation detectors. Full chapters have been devoted to gas-filled counters, scintillation detectors, and semiconductor detectors. Detectors with special functions are discussed in Chap. 17. 

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