About Radiation Detectors - Advantages & Disadvantages

 

About Radiation Detectors - Advantages & Disadvantages

Introduction

Each type of radiation detectors has its advantages and disadvantages. A wide range of detectors exist for measuring and quantifying ionizing radiation.  The selection of a radiation detector is guided by measurement requirements. Some detectors can quantify radiation energy, where others only count ionizing events. The design and shielding of a radiation detector also affect its sensitivity to different ionizing sources, including alpha, beta, and gamma radiation.  

Those incorporating GM tubes, are more commonly used due to ease of handling, low cost, and accuracy, and reliable. For applications where high efficiency for gamma radiation is needed, scintillation devices are best. Gamma Scintillation detectors are commonly used in medical applications such as digital radiography, fluoroscopy or CT scans. Most scintillation detectors will not detect alpha or beta radiation.

Geiger-Müller Detectors

Geiger tubes are rugged and relatively inexpensive to manufacture. The design of a GM detector or Geiger counter strongly affects its sensitivity to alpha, beta, and gamma radiation sources each having different penetrating characteristics. Geiger-Müller detectors for alpha and beta radiation commonly use tube geometries with an ultrathin window to increase the likelihood that less penetrating radiation will reach the inside of the detector. The detection of gamma radiation results primarily from the interaction of gamma rays with the sidewall of the detector. The chamber geometry, gas, wall material, and thickness are all design factors in the sensitivity limits of GM detectors.

Scintillation Detectors

Scintillation detectors are used when quantification of ionizing energy is of interest. They utilize the interaction of ionizing radiation to produce UV and/or visible light. A calibration transfer function allows the intensity of captured light to be related to the energy of the incident radiation. The majority of light conversion in scintillation materials occurs via fluorescence. Fluorescence allows for fast detector response times and quantification of moderate- to high-level radiation. Scintillation materials are chosen based on the type of radiation to be measured.

Solid-State Detectors

Solid-state detectors based on semiconductor diodes are used when improved energy resolution and radionuclide identification capabilities are required. These detectors rely on the production of electron-hole pairs within a diode depletion region resulting from incident ionizing radiation. In a solid-state device under a reverse bias, these charge carriers can be directly swept to electrodes producing a current signal before recombining. Solid-state detectors can offer greater energy resolution than scintillation detectors.

There are several limitations associated with the use of solid-state detectors. To increase the diode depletion region which forms the interaction volume of the detector, production of high-purity semiconductor materials, like silicon or germanium, is required. Leakage current in the diode due to room-temperature excitation of charge carriers can significantly degrade the noise performance of solid- state detectors. Cooling to cryogenic temperatures is generally required for optimal resolution and operation. Solid-state detectors and spectrometers are typically more expensive than alternative technologies.

Conclusions

Additional classes of detectors exist. Each detector type possesses unique advantages and disadvantages depending on survey requirements. Understanding of the differences between detector designs and capabilities can help facilitate interpretation and discussion of radiation measurements. Contact S.E. International for assistance with your radiation detection needs.

 Uses and advantages of metal detectors

•  Pursuing of hobbies- such hobbies may include coin shooting activities, beach combing, and detection of buttons, bullets and exe heads.
•  Security screening - They are used in airports to screen passengers, checking bags in public places and in public events.
•  Food processing - They are used in food processing industries to detect fragments of metal so as to avoid food contamination.
• Civil engineering - They are used in finding reinforcement bars inside the walls.

 

Disadvantages of metal detectors

•  False alarm - Metal detector may give a false alarm incase an individual carries a metal object such as phone, watch or a toy causing unnecessary panic.
•  Interference - Metal detectors may interfere with personal devices such as magnetic recording gadgets like CD or a cassette.
•  A metal detector is not safe with people who had to get a pacemaker or replacements such as a knee replacement.

Tips and guide when purchasing a metal detector

•  Intended use- When buying, it is a good idea to determine the use of the equipment so as to purchase the right one. Different metal detectors are usually configured for different kinds of searching hence features desirable in a detector depends on the purposed use. Different types of detectors and their uses are:
• All-purpose Metal Detectors - For versatile searching and casual finding of metal objects
• Relic and coin detectors - For finding small and medium sized relics and coins in littered areas.
• Gold detectors- For finding deposits of gold-
• Underwater detectors - For searching on underwater and beaches.
•  Price - A cheap or too much expensive and complicated detector should not be purchased. A good detector enough to get the job well done should be purchased.
• Conformability weight- An individual should buy a detector which feels comfortable when working with in terms of weight.
• Warranty- there are different varying warranty policies from different manufacturers, some being good for one year while others taking a lifetime of the original owner.
•  Features - A detector with the best features should be purchased so as to get good job done.

Myths of metal detectors

• Metal detectors dependence on X-ray technology- metal detectors uses the technology of electromagnetic fields in finding metal objects and then sending out an audible signal to the user.
• One can use the detector gadget wherever he wants- this is not true because private property laws have to be followed. Treasure hunters are usually prohibited in government lands and historical sites without being authorized.
• Experts are the only who finds valuables- This is not correct because anyone can use the detectors to find treasures.

Conclusion

Metal detection is a nice hobby for individuals who may wish to find buried treasure, jewelry and coins which have been left behind on beaches, parks and historical relics. Seasoned and beginner’s hunters requires detectors that offer the best features so as to make their expeditions very successful. Determination of the ways in which the purchaser of a metal detector will use it is very essential so as to help in choosing and buying the product and its accessories.