Radiation level detector

What happens if the coke drum gets too full of resid Add a radiation level detector to notify the microcomputer when the drum is full so it can switch resid to the other drum which it has determined to be empty. 

In addition to the level-measurement devices illustrated in Figure 7-3, there are air bubbler systems for level detection, ultrasonic level detectors, and radiation level detectors. Ultrasonic and... 

Sometimes the radiation level detector (especially when the more sensitive neutron back-scatter devices are used) will falsely indicate that the water level in the coke drum has risen to the correct level. Apparently, the level detector is fooled by the increasing density of steam as the coke cools. 

But let me be completely honest. 1 once had a radiation level detector on a spent sulfuric acid tank. 1 was the operating superintendent at this plant, which regenerated sulfuric add. We had a not-so-small fire at this tank. Rather than repair the tank, pumps, and lines, 1 decided to dismantle and haul away the entire mess of steel. After all, 1 had much larger and more modern storage tanks at my disposal. 

For this kind of case, a modification of the dilution method is being developed. Instead of using an external fixed-geometry measurement chamber, a suitable part of the process, e.g. a stretch of pipe, is used. A radiation detector is mounted on the outside of the pipe, and a tracer emitting sufficiently hard gamma radiation is used. As sufficient mixing can be achieved by injecting upstream the separator the radiation level found will be strictly proportional to the concentration and thus inversely proportional to the true flow rate. 

Measurements of liquid density are closely related to quantity and liquid-level measurements since both are often required simultaneously to establish the mass contents of a tank, and the same physical principle may often be used for either measurement, since liquid-level detectors sense the steep density gradient at the liquid-vapor interface. Thus, the methods of density determination include the following techniques direct weighing, differential pressure, capacitance, optical, acoustic, and nuclear radiation attenuation. In general, the various liquid level principles apply to density measurement techniques as well. 

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. 

Radiation-type level detectors can be point source, multiple source, strip source, motorized tape-supported traveling source, or backscatter types with cesium-137 or cobalt-60 (for thick-walled tanks) source materials. The ranges of external units are up to 7 m (23 ft) and of the traversing backscatter-type units up to 45 m (150 ft). Measurement errors range from 6 mm to 1% FS. 

The designs of tank farm level detectors include (1) wire-guided float, (2) servo-operated float, (3) surface detector (plumb-bob), (4) radiation backscatter, (5) radar, (6) HTG, and (7) hybrid gauges. Their ranges go up to 60 m (200 ft). 

The detector in some inexpensive filter fluorometers is a phototube, but in most of the better filter fluorometers and in all spectrofluorometers a high-gain photomultiplier tube is used. The photomultiplier is far more sensitive to low radiation levels and is therefore recommended for trace analysis. 

Due to its low operating temperature, the detector element is covered by a vacuum enclosure with an optical window in front of the detector element. The vacuum housing makes the MCT detector rather expensive. Furthermore, the MCT detector shows nonhnear response, which can be minimised by special electronics and software. The time needed to scan one spectrum is only 0.01 s, i. e. rates of 100 scans per second are achieved. The MCT is the detector of choice for experiments in conditions of low radiation levels. 

These effects have been used by investigators to reduce the background radiation levels in x-ray spectroscopy. For Bremsstrahlung radiation, the maximum polarization vector is parallel to the electron path in the x-ray tube. In many conventional-wavelength spectrometer designs, the specimen and crystal surfaces will become parallel when 26 equals the takeoff angle 2 ( 45°). In addition, the x-ray tube axis and the rotational axes of the crystal and detector are parallel. This so-called parallel optics cannot take advantage of the polarization of the white spectrum. If, however, the surface plane of the crystal and specimen remain perpendicular... 

You should take a background reading with your beta-gamma detector prior to entering the hazard area. Record this as the normal ambient radiation level. 

The sensitivity should be considered as the ability of an instrument to detect and quantify low concentrations of the target compound. In absorption spectrometry, low concentration of the analyte means high transmitted radiation levels. This is the reason why the poorer sensitivity of silicon-based photodiodes compared to photomultipliers or coupled charge detectors is in fact not so important. The relatively lower sensitivity of photodiodes is also compensated... 

Devices equipped with detectors and radiation level monitors are posted inside rooms of a workplace. They usually measure the external radiation continuously. Their alarm levels are... 

A survey counter is a gas filled detector used to detect spilled radioactive materials that can be hazardous for the operators or may disturb accurate dose measurements. Survey counters can be mounted at critical places to measure the radiation level in rooms continuously. A hand-foot-clothing monitor is a suitable and obligatory instrument to detect possible contamination before leaving the area where radioactive materials are handled. 

Personal radiation exposure can be measured using a film badge, which is worn by the employee over a fixed time interval. The badge contains a photographic film which, after the time interval, is developed and an estimate of radiation exposure is made. A similar device, known as a radiation dose meter or detector, can be positioned on a shelf in the workplace for three months, so that a mean value of radiation levels may be measured. Instantaneous radiation values can be obtained from portable hand-held instruments, known as geiger counters, which continuously sample the air for radiation levels. Similar devices are available to measure radon levels. 

As indicated by the radiation coke drum level detector, the full coke drum s liquid level suddenly rises. 

---