Frequently Asked Questions / Search

Common Questions

Will The Observer USB work with older models of Radiation Alert® Detectors?

No. However, the Serial Observer Software will work and includes the cable to connect your detector to a computer via the 3.5mm headphone jack.

How do I turn on the data logging on my SEI Inspector USB, SEI Inspector Xtreme USB, SEI Inspector EXP or Digilert 200?

You can do this one of two ways. You can turn on the data logging via the Utility Menu on the unit itself. You can access the Utility Menu by holding down the plus button while powering on your detector. Set the date and time first, then turn on the recording feature. You can also turn on the data logging with the Observer USB Software by synching the time and date of your computer and turning on the data logging via the Cal Panel.

How often should I calibrate my detector?

We recommend your instrument be calibrated annually from the date it was placed in service, but certain industries or applications may require them more frequently. For more information on how to calibrate your device, please click here.

What levels of radiation are considered safe?

For the best information on what levels of radiation are considered safe, it is best to consult a Radiation Safety Professional. For your convenience, we have included a list of useful links below to assist you in finding the information you need. You can also check out our growing list of General Radiation Info FAQs

Radiation Info Links

| RadiationAnswers.org
| HPS.org
| CRCPD.org is a great source for information on regulations and radiation safety officers in your area.
| ENENEWS.net
| Our Radiation FAQs
| Radiation Basics
| What Are Safe Levels of Radiation?

Can I use Radiation Alert Detectors on microwaves, radar, and cell phones?

NO! CAUTION! DO NOT PLACE OUR INSTRUMENTS IN A MICROWAVE AS IT MAY DAMAGE THE INSTRUMENT OR THE MICROWAVE OVEN.

Our instruments detect ionizing radiation. Microwaves are non-ionizing radiation. For more information on the differences between ionizing (sometimes called nuclear, alpha, beta, gamma, neutron, or x-ray radiation) and non-ionizing (cell phones, microwaves, wireless, and radar), please refer to the electromagnetic spectrum.

Are there any websites available that show information about radiation levels in my area?

For your convenience, we have included a list of useful links below showing the various radiation levels in your area. For information on radiation levels displayed on the various maps available, please contact the host of the site where the data is displayed.

Radiation Map Websites

| RadCast.org

| Safecast.org

| EPA RadNet

| RadViews.com

| National Radiation Tracking Center

Can I use a gieger counter, like The SEI Inspector Family of detectors, to detect radiation in food?

A Geiger counter is a "Yes or no and how much" type of detector. They cannot determine the distribution of the incident radiation energy, so they cannot identify which potential isotopes are present. To identify specific isotopes, a radiation spectrum analyzer with a sensitive enough scintillation detector for the application would be necessary. Geiger counters are ideal for basic screening, especially if you do long timed counts and, in most instances, will give you an indication regarding foods that are significantly contaminated.


When using a Geiger counter to test food, you should take into consideration that the meter is likely missing a bit of the radiation. This is due to the shielding of the radiation by the density of food, and the limitations posed by the detection range of the meter. Alpha radiation can be detected on the food's surface, but can be blocked if there is internal contamination. You can better test food by grinding it into a paste and taking a timed count. This may give an indication that you have contamination in your food, though it will not qualify what type of radiation may be present in the sample.


Water and food can also be a shield for radiation, so unless there is gamma radiation our instruments are not the most ideal without a little processing of the material in question (beta and alpha will not move very far in water and will be shielded by it). You can take a sample of the water and run it through a filter and test the filter or you can evaporate it down and test the swipe on an SEI Inspector USB with a Wipe Test Plate, however, the URSA-II with the appropriate detector would be much more efficient for this application, but scintillation based instruments are more expensive than the handheld GM based alternatives. Regardless, most of the higher energy betas and gamma radiation that falls within the sensitivity of the detector will be measured.


It is important to remember to establish a background count prior to surveying your samples. To do this, use your SEI Inspector in the Timed Count mode and take a background count of at least 10 minutes. Then, divide the total counts displayed on the unit by the number of minutes of your count. For instance, if you take a 10 minute timed count, divide the total counts by 10. If you're taking a 24 hour background count, then divide the total by 1440 (the number of minutes in a 24 hour period) to get your Counts Per Minute background level. The longer you take a timed count, the more statistically accurate your reading will be. You will then subtract that amount from the readings of your sample.

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Posted by S.E. International, Inc. on Wednesday, June 10, 2015