Selecting a Gamma Imager

Not everyone has the same needs for a gamma imager. The table below ranks 8 different factors to consider when buying a gamma imager, and how important those factors are for 6 different applications.

Not sure how to evaluate the specifications of a specific gamma imager? Check out our article about which attributes are important and how to evaluate them here.


Application

Nuclear Power Plant
Health Physics
CBRNE Emergency
Tracking Active
Contamination
Source Search at
Background Levels
Controlled Env.
Quantification
Explosive Ordinance
Disposal
Customer Service Measure high
dose rates
Imaging
low-E
isotopes
Imaging
high-E
isotopes
Field of View Fieldability Angular resolution Energy Resolution
arrow_upward arrow_upward arrow_downward arrow_upward call_made call_made arrow_forward arrow_forward
arrow_upward call_made arrow_upward call_made call_made arrow_upward arrow_forward call_made
arrow_upward arrow_upward arrow_downward arrow_upward call_made arrow_upward arrow_forward arrow_forward
arrow_upward arrow_downward arrow_upward call_made arrow_upward arrow_upward arrow_forward arrow_upward
arrow_upward call_made call_made arrow_forward arrow_downward arrow_forward arrow_upward arrow_upward
arrow_upward call_made arrow_upward call_made arrow_downward arrow_upward arrow_upward call_made

arrow_upward: Most important, call_made: Important, arrow_forward: Somewhat important, arrow_downward: Not important

These applications are general and your specific needs might not fit perfectly, so we recommend reading through all of the following paragraphs to determine which is closest to your situation.

Across all applications, it is important to purchase a gamma imager from a company you are certain has great customer service. If that company cannot quickly respond to questions or give you complete answers, it is not in your best interest to purchase from them.

Nuclear Power Plants and Related Industries:

Customer Service arrow_upward
Measure
high dose rates
arrow_upward
Imaging
high-E isotopes
arrow_upward
Fieldability call_made
Field of View call_made
Energy Resolution arrow_forward
Angular Resolution arrow_forward
Imaging
low-E isotopes
arrow_downward

arrow_upward: Most important, call_made: Important,
arrow_forward: Somewhat important, arrow_downward: Not important

We expect that you are interested in localizing or imaging high-energy sources, such as cobalt-60 with count rates significantly above background levels. You also probably will need to image distributed sources. Not every imager can give a high-quality radiation image for high-energy sources, high count rates, or distributed sources.

When you are measuring sources with count rates significantly above background levels, it is important to note which gamma imagers can handle measurements at the dose rates you expect. Efficiency is not as important for this application, since you will quickly get many counts in the high-dose-rate environment. This is why it is important to always try the imager out via a demonstration in your facility. A demonstration will show you whether or not an imager will be successful at your facility.

Generally, these applications require portability, great battery life, and a wide field of view in order to effectively use the imager.

CBRNE Emergency Response:


Customer Service arrow_upward
Imaging
low-E isotopes
arrow_upward
Field of View call_made
Measure
high dose rates
call_made
Imaging
high-E isotopes
call_made
Fieldability call_made
Energy Resolution call_made
Angular Resolution arrow_forward

arrow_upward: Most important, call_made: Important,
arrow_forward: Somewhat important, arrow_downward: Not important

If you primarily plan on using a gamma imager for emergency response operations, such as dirty-bomb response, fieldability should be your primary concern. Not all gamma imagers can easily be ready to use in the field. Be sure to confirm you understand the weight, weather resistance, battery life, temperature sensitivity, and startup time of a gamma imager prior to purchase.

In addition, ensure the equipment is easy to use with minimal training. Users should be able to pick up and operate the system easily in the field.

Emergency Response: Tracking Active Contamination-Spreading Event:


Customer Service arrow_upward
Measure
high dose rates
arrow_upward
Imaging
high-E isotopes
arrow_upward
Fieldability arrow_upward
Field of View call_made
Energy Resolution arrow_forward
Angular Resolution arrow_forward
Imaging
low-E isotopes
arrow_downward

arrow_upward: Most important, call_made: Important,
arrow_forward: Somewhat important, arrow_downward: Not important

A moving source requires different features of an imager than other emergency-response scenarios. Portability is certainly of even greater importance, since the non-stationary radiation needs to be continually tracked. The moving source could be anything from measuring dirty-bomb plumes to a radiological release at a nuclear power plant. For these types of applications, high imaging efficiency is very necessary since you want to detect as many particles as possible in order to create an accurate image. Due to the dynamic source, you should also look for gamma imagers that have features to handle real-time imaging of a changing environment.

Source Search at Background Levels:

Customer Service arrow_upward
Fieldability arrow_upward
Imaging
low-E isotopes
arrow_upward
Field of View arrow_upward
Energy Resolution arrow_upward
Imaging
high-E isotopes
call_made
Angular Resolution arrow_forward
Measure
high dose rates
arrow_downward

arrow_upward: Most important, call_made: Important,
arrow_forward: Somewhat important, arrow_downward: Not important

If you are primarily searching for sources in the field or other dynamic environments, your first step is to determine which emission energies you expect to see in your measurements. Not all gamma imagers can accurately image sources at the energies in which you might be interested. If you are looking for low-energy sources, you will want a system with coded aperture or pinhole imaging. Keep in mind that pinhole imaging is less efficient than coded aperture imaging. If you are looking for high-energy sources, Compton imaging is well suited. The various imaging methods have different limitations. For instance, a detector with only coded aperture imaging can image sources as high as 1 MeV, but is not ideal for a search mission because of the limited field of view and challenges with using the same mask at high and low energies. Many other Compton cameras also have a limited field of view, whereas H3D's Compton cameras do not.

It is also important to consider the efficiency of an imager, since you are expecting to identify and localize radiation sources while near background count rates. Portability and a long battery life are also necessary considerations for applications where the imager will be in the field for long periods of time.

Energy resolution is also an important specification for Source Search at Background Levels. Better energy resolution will help you see peaks on a continuum, accurately determine the energy and area of the peak, and distinguish between nearby peaks of similar emission energies.

Controlled-Environment Quantification:

Customer Service arrow_upward
Energy Resolution arrow_upward
Angular Resolution arrow_upward
Measure
high dose rates
call_made
Imaging
low-E isotopes
call_made
Imaging
high-E isotopes
arrow_forward
Fieldability arrow_forward
Field of View arrow_downward

arrow_upward: Most important, call_made: Important,
arrow_forward: Somewhat important, arrow_downward: Not important

If you plan on characterizing and quantifying sources in a controlled environment, we recommend determining which emission energies you expect to see in your measurements, since not all gamma imagers can image over a wide range. Applications such as waste analysis or shipping inspections might require your imager to be capable of quantification in the field. Some gamma imagers even come with extensive post-processing software that allows for in-depth quantification, geometry analysis, and advanced imaging options. Since typical applications in this category are often performed in a stationary, controlled environment, features such as battery life, field of view, and portability aren’t as critical for successful operation, but you may need to evaluate based on your own specific application.

Energy resolution is also an important specification for Source Search at Background Levels. Better energy resolution will help you see peaks on a continuum, accurately determine the energy and area of the peak, and distinguish between nearby peaks of similar emission energies.

Explosive Ordinance Disposal (EOD):


Customer Service arrow_upward
Fieldability arrow_upward
Angular Resolution arrow_upward
Imaging
low-E isotopes
arrow_upward
Measure
high dose rates
call_made
Imaging
high-E isotopes
call_made
Energy Resolution call_made
Field of View arrow_downward

arrow_upward: Most important, call_made: Important,
arrow_forward: Somewhat important, arrow_downward: Not important

If your team needs to scan a package to render it safe, we recommend a system that can successfully identify sources with a wide range of energies. Characterizing the radiation source is a high priority as well as fieldability. If the imager can’t be transported easily and takes a while to set up, you are potentially putting your team at risk. Angular resolution is important so that the specific distribution of isotopes can be found in the package without disturbing the contents.

Thanks for reading! Remember, different imagers are suited for different applications. Make sure you have the best fit before buying!

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