Radiation Detection and Survey Devices

Key Radiation Detection Device Monographs and Articles

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For more information, please visit Nuclear & Electronics.

Introduction and Basic Information

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Review of Radiation Dosimeters Types for Dose Monitoring, Worker Safety, and Environmental Monitoring

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Selection of Radiation Detection Devices by Radiation Incident Response Zone

Table 2. Comparison of Radiation Devices by Preferred Response Zone

Source: Radiation Dosimeters for Response And Recovery, Market Survey Report (PDF - 1.87 MB) (DHS/OSTP/NUSTL, June 2016, page 9)

• This graphic shows that no one device is appropriate for every situation.
• The x-axis on the bottom of the table above is exposure rate (R/h)
• The x-axis on the top corresponds to Response Zones (Cold, Hot, Dangerous-radiation) where each dosimeter might be most useful. Definition of response zones is shown on the graphic, but various groups have defined the zones differently.
• The y-axis on the left of the graphic lists types of dosimeters that are appropriate for that work area
• In the source document for this table, the many categories of dosimeters are mentioned with many individual products listed for each type.

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More about Selected Examples of Detection Devices

Geiger Mueller (GM) Detectors with Pancake Probes

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Alpha Radiation Survey Meter

• Radiation survey meter with probe appropriate for detecting alpha radiation.
• Alpha Scintillation Detectors (Part 3) (YouTube - 3:54 minutes) (HHS/CDC)

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Dose Rate Meter

• This survey meter measures environmental levels of penetrating, ionizing radiation
  • May be used to determine whether it is safe to enter an area and, if so, for how long
  • Provide readings in units of roentgens per unit time (e.g., mR/hr)

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Personal Dosimeters

• What is a personal dosimeter?
  • A small radiation monitoring device worn by persons entering environments that may contain radiation
  • See historical collection of personal dosimeters (ORISE)
• Who should wear a personal dosimeter?
  • Healthcare or laboratory workers in non-emergency environments that may contain radiation
    • Examples: radiology, nuclear medicine, and radiation oncology department staff
  • Workers in emergency environments that may contain radiation
    • Examples: first responders and first receivers
  • Workers in industrial environments where radiation is used
    • Examples: nuclear power plant workers or employees at radiation sterilizing facilities
• Where are personal dosimeters usually worn?
  • Flat badges are usually worn on the torso, at the collar or chest level, but can be worn on the belt, or forearm
  • Ring shaped badges can be worn on the finger when dose to the finger may exceed dose to the badge worn elsewhere on the body
  • First responders and first receivers
    • Wear water-resistant personal dosimeters on the outer layer of personal protective equipment (PPE).
    • Should be able to easily see and hear a dosimeter alarm while wearing PPE
    • May wear a personal dosimeter underneath waterproof outerwear
• CAVEATS:
  • Radiation exposure in the environment may not be uniform.
    • Dose registered by a badge worn on the torso may not be the same as dose received elsewhere on the body.
    • When working close to radiation sources (e.g., removing radioactive shrapnel), the hands/fingers may receive a higher dose than the torso, and should be monitored by a personal dosimeter on the finger.
  • Real time readings from personal dosimeters are not available from all devices.
  • Emergency responders may require self-reading devices that provide dose information in real time.
• Types of personal dosimeters
  • See REMM table which reviews many types of personal dosimeters
  • Non-self reading dosimeters: real time dose information not available
    • Film badges
      • Contain filters and film which identify and quantify the type of radiation (e.g., x-rays, gamma, beta, neutron)
      • Least accurate personal dosimeter for recording very low exposure (e.g., below about 10 mR)
      • Sensitive to temperature and humidity, which may limit use by emergency responders
      • Available for use on torso and finger
      • See historical collection of personal dosimeters (ORISE)
    • Thermoluminescent dosimeters (TLDs)
      • More sensitive than film badges
      • Some can measure readings lower than film badges
      • Use lithium fluoride crystals to record radiation exposure
      • Not sensitive to heat and humidity
      • Available for use on torso and finger
      
      
      
      
    • Optically stimulated luminescence (OSL) dosimeter
      • More recent device of choice for occupational exposure monitoring
      • More sensitive than film badge or TLD
      • Use aluminum oxide to record radiation
      • Results can be read up to a year following exposure
      • Available for use on torso and finger
      
      
      
      
      
  • Self-reading dosimeters (aka. direct-reading dosimeters, self-reading pocket dosimeters, pocket electroscopes): provide real time dose information
    • Older types: See historical collection of personal dosimeters (ORISE)
      • Dose is determined by looking through the eyepiece on one end of the dosimeter, pointing the other end towards a light source, and noting the position of the fiber on a scale

      
      

    • Newer types
      • Electronic
      • Some can measure and display dose rate and total dose
      • Some can alert wearer that pre-set dose rate and/or total dose limits have been exceeded by both visual and vibrating alarms
      • Dose rate and total dose readings can be downloaded in real time to a computer
      • Some are designed for use in extreme environments by emergency responders wearing bunker gear or higher-level PPE (See examples below)
      
      
      
      
      
      
      
      

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Portal Monitors

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Multimedia Training about Radiation Detection Devices

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If you are looking for more details, kindly visit radiation detection and measurement solutions.

Selected References

Disclaimer:
Reference on this page to any specific commercial product, process, service, manufacturer, or company does not constitute its endorsement or recommendation by the U.S. government or the U.S. Department of Health and Human Services or any of its agencies. Products are displayed as examples only. HHS is not responsible for the contents of any "off-site" Web page referenced on this site.

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I've stumbled upon a strange class of Android applications lately. (And I'm sure such applications are available for other platforms too.)

These apps claim the ability of detecting radiation. The mechanism would be gamma rays hitting the light detector and causing ionization much the same way as visible light photons do.

I own a small collection of radioactive minerals. I also built an ionization chamber detector that can hardly detect a small uranium glass bead, can show the presence of 2% thorium in a tungsten welding rod with confidence, goes right off near any of my minerals, and an americium source utterly throws it off-balance.

I understand the suggested mechanism of action of these apps, and without doing the math, it seems not-so-impossible.

Of course I've tested one of them with a recent smart phone with a sensitive and high resolution camera. Measurements all came out negative: same amount of radiation measured next to me on the table than among pieces of gummite, autunite, pitchblende, tyuyamunite, liebigite, thorite, younameit ;)

I've got upset by the fact that maybe I've been fooled to pay the ~$10 for the premium version of one of these magical applications, and decided to do a detailed analysis on images from a webcam built into my notebook covered with black electric tape.

First I've verified that the cover works by looking at the images from the camera with a desktop application. The images were all pitch black.

I than have written a python script that takes images, highpass-filters every individual pixel and all three color channel (to cancel "hot pixels" and similar artifacts and concentrate on changes), and calculates the average (for sanity check) and standard distribution of the tremendous amount of 1 byte samples.

The images are of a resolution of 1280x720 pixels, therefore each image consits of $1280 * 720 * 3 = 2,764,800$ samples. Taking ten thousand of these gives one $2.76*10^6*10^4 = 2.76*10^{10}$ samples. I consider this quite a lot.

I base my trust in this amount on the very much less amount of data taken by the application. It might take a few dozen or maybe a hundred pictures, but nothing more. The app simply doesn't run that long.

If the light detector inside the camera would react even weakly with the gamma (and maybe beta) radiation from the minerals, pixels should light up here and there, pushing the distribution wider.

The average was something around $10^{-3}$ (and getting closer to zero as one might expect), and the standard deviation was about $3*10^{-3}$ both in the presence and absence of radioactive minerals.

My questions are:

• Do you think one can ever detect such levels of radiation with a camera?
• Does my experiment make sense?
• Does it suggest that the claims these app developers make are... not entirely true?

Thank you in advance.

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