Radiation sensors

Radiation sensor fails Fail to detect critical condition and fails to initiate bed separation High Redundant detectors are used. In addition technicians have personal audible (cherper) nioniioi s to alert to an incipient critical condition. 

The beam of the radiation passing through the studied object interact with the material that induces a certain scattering pattern of the reflected radiation detectable by the radiation sensors. This scattering is caused by the... 

In Chapter 5.4, optical ultraviolet radiation sensors are described, including UV-enhanced silicon-based pn diodes, detectors made from other wide band gap materials in crystalline or polycrystalline form, the latter being a new, less costly alternative. Other domestic applications are personal UV exposure dosimetry, surveillance of sun beds, flame scanning in gas and oil burners, fire alarm monitors and water sterilization equipment surveillance. 

In modern systems, the applied electric power is increased over time to compensate for the decreasing intensity. However, this adjustment uses the average degradation curve of a lamp as a reference, not the actual values of the lamps mounted in a particular sunbed. A radiation sensor could be used to control an active circuit that regulates the intensity of radiation. 

Elements sensitive to piezoelectric thermal oscillation Pyroelectric sensors Black-body radiation sensors... 

In terms of the interaction of light with matter, extrinsic sensors can be compared with non-guided radiation sensors because light temporally exits the... 

When the application involves foaming, one must detect both the liquid-foam interface and foam level. Radiation sensors can detect the liquid-foam interface and TDR transmitters, or conductance and RF switches can detect the foam level if it is conductive. In the case of heavier foams, vibrating or tuning-fork switches and beta-radiation gauges have been used in some cases, optical or thermal switches have also been successful. 

When detecting the interface between two liquids, electrical conductivity, thermal conductivity, opacity, or sonic transmittance of the liquids can be used. Interface-level switches are usually of the sonic, optical, capacitance, displacer, conductivity, thermal, microwave, or radiation types. Differential pressure transmitters can continuously detect the interface, but, if their density differential is small relative to the span, the error will be high. On clean services, float- and displacer-type sensors can also be used as interface-level detectors. In specialized cases, such as the continuous detection of the interface between the ash and coal layers in fluidized bed combustion chambers, the best choice is to use the nuclear radiation sensors. 

The detector best suited to meet these conditions is a radiation type sensor. Ultraviolet (UV), infrared and visible radiation are generated when combustion produces a flame and all three types of radiation sensors respond to the radiation from the flame. 

If the chamber has built-in radiation sensors to measure radiation intensity then these sensors must also be calibrated against a qualified standard. As with the temperature and humidity probes, the radiation sensors should agree within a specified tolerance with instrument error taken into consideration. 

Radiation sensors are now available for the detection of even the most nonluminous flames. These can be used to sound an alarm and actuate deluge systems if desired. At least one commercial unit also reveals the location of the flame by superimposing its image on a television monitor. ... 

An analytical study has been conducted and has demonstrated theoretically that the concept of a solid cooling system is feasible. An experimental program has verified that this system, with a modest charge of coolant, could provide cooling to such components as radiation sensors for extended periods of time. 

Saura, I (1994), Gas-sensing properties of SnOj pyrolytic films subjected to ultraviolet radiation Sensors and Actuators B Chemical, 17,3,211-14. 

Chalmen AJ. Poly(ADP-ribose) polymerase-1 and ionizing radiation sensor, signaller and therapeutic target. Clin Oncol (R Coll Radiol) 2004 16(l) 29-39. 

Ionization or radiation sensors that use the tendency of a radioactive substance to ionize when exposed to smoke. The substance becomes electrically conductive with the smoke exposure and permits the alarm circuit to be completed. 

A reflective-radiation sensor as a high limit might be practical. It is difficult to measure (detect) scaling, thus, it is not very practical to adjust for, or automatically prevent, its formation. Operators and supervisors must rely on knowledge and experience to anticipate scale problems and prepare to avoid or forestall them. (See sec. 8.3.)... 

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