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Radiation Alert MONITOR4USB Analog-Based Ionizing Radiation Detector

4.0 out of 5 stars 1 customer review

Price: $404.00 & FREE Shipping. Details
Only 3 left in stock (more on the way).
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Specifications for this item
Brand Name Radiation Alert
Number of Items 1
Item Weight 1 pounds
Temperature Range neg 4/131  Degrees Fahrenheit
UNSPSC Code 26142300

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Product Features

  • Radiation detector used to check levels of potentially harmful ionizing particles and rays in the environment and in objects such as particle accelerators, x-ray shielding, and industrial gauges
  • Detects ionizing radiation types such as alpha and beta particles, and gamma rays and x-rays
  • Dual-scale analog meter with needle-point display of counts per minute (CPM) and milliRoentgen (mR) per hour
  • Three selectable operation ranges of X1, X10, and X100 for adjustment when peak mR levels are met
  • Mini-USB Port for connecting an external device

Product Description

The Radiation Alert Monitor 4USB is a hand-held radiation detector with a mini-USB port, and an analog display over three selectable operational ranges for detecting potentially harmful ionizing alpha and beta particles, and gamma and x-ray radiation. This meter has a dual-scale, analog, needle-point display of counts per minute (CPM), and milliRoentgen (mR) per hour. It detects the four main types of ionizing radiation: alpha and beta particles, and gamma rays and x-rays. It has three selectable operational ranges (X1, X10, or X100) to be adjusted when the meter face peaks at the highest mR level.

The Monitor 4USB has a red, flashing counter and a beeping noise to indicate each ionizing radiation event. An enclosed halogen-quenched Geiger Mueller (GM) tube with a thin, mica end window senses ionizing radiation. The detector is used to check radiation levels in the environment and objects, such as particle accelerators, x-ray shielding, and industrial gauges. An audio indicator with an internally mounted beeper can be turned off for silent operation. The Monitor cannot be returned.


Reading Ranges 0 to 0.5, 0 to 5, or 0 to 50 milliRoentgen (mR) per hour, or 0 to 500, 0 to 5,000, or 0 to 50,000 cycles per minute (CPM).
Accuracy Factory-calibrated by pulse generator, with accuracy + or -15% of reading full-scale, relative to Cesium 137.
Energy Sensitivity 1,000 CPM/mR/hr (Cs137).
Detection Alpha down to 2.5 mega (million) electron volts (MeV), with typical detection efficiency at 3.6 MeV at greater than 80%.
Beta at 50 kilo (thousand) electron volts (keV) with typical 35% detection efficiency.
Beta at 150 kilo (thousand) electron volts (keV) with typical 75% detection efficiency.
Gamma and x-rays down to 10 keV typical through the window, 40keV through the case.
Temperature Range -20 degrees to 55 degrees C (-4 degrees to 131 degrees F) and an internal detector.
GM Detector Halogen-quenched with window thickness of 1.5 to 2.0 mg/cm2. The effective diameter is 0.92 cm/0.36”.
Dimensions Dimensions are 209 mm x 71 mm x 50 mm (8.2” x 2.8” x 1.9”).
Weight 178 g (6.3 oz).
Output Mini USB port for connection to an external drive.
Normal Background Radiation Approximately 5 to 20 CPM.
Battery 9-V alkaline battery (not included) for approximately 2,000 hours of continuous use in a normal background.

Radiation detectors can detect a broad range of ionizing alpha and beta particles, and gamma and x-rays that may be emitting harmful levels of radiation. They sense ionizing radiation with an enclosed Geiger Mueller (GM) tube to count radiation particles or rays. Alpha and beta particles are measured in counts per minute (CPM) or counts per second (CPS). Gamma rays and x-rays are measured in milliRoentgens (mR) per hour, microSieverts (μSv) per hour, or milliSieverts (mSv) per hour. Alpha particles are positively charged and heavier than beta particles, and have a limited range of approximately 3 to 5 centimeters by air. Alpha particles can be shielded by objects such as paper and unopened skin. High-energy beta particles are electrons, heavier than gamma rays, and can take either a positive or negative charge. Beta particles can be shielded by aluminum or wood. High-frequency (short wavelength) gamma rays are the strongest and lightest rays. Gamma rays are more penetrating than alpha and beta particles. They can be shielded by dense materials such as lead, and large masses of concrete, hardened steel, or water. X-rays are man-made gamma rays, and have essentially the same properties and function. Radiation detectors commonly have either an analog or a digital display. Analog radiation detectors output with a needle-point scale, and digital units generate a numerical LCD digit display. Radiation detectors are commonly used by hobbyists for safety detection and rock inspection, and professionals in the in the nuclear, medical, mining, instructional, and research industries.

SE International manufactures radiation detection products and accessories under the Radiation Alert brand. The company was founded in 1979 and is headquartered in Summertown, TN.

What’s in the Box?

  • Monitor 4USB radiation detector
  • Carrying case with belt clip
  • Mini-USB cable
  • Instruction manual
  • Conformite Europeene (CE) certification

Product Details

User Manual [301kb PDF]| Spec Sheet [2.02mb PDF]
  • Item Weight: 1 pounds
  • Shipping Weight: 1 pounds (View shipping rates and policies)
  • Domestic Shipping: Currently, item can be shipped only within the U.S. and to APO/FPO addresses. For APO/FPO shipments, please check with the manufacturer regarding warranty and support issues.
  • International Shipping: This item is not eligible for international shipping. Learn More
  • Average Customer Review: 4.0 out of 5 stars  See all reviews (1 customer review)
  • Amazon Best Sellers Rank: #515,873 in Industrial & Scientific (See Top 100 in Industrial & Scientific)
  • Manufacturer’s warranty can be requested from customer service. Click here to make a request to customer service.

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Top Customer Reviews

By Robert A. Sikorski on July 25, 2012
Verified Purchase
Amazon just delivered this product to me for free in four days! Thanks!
Radiation detector is working, background radiation in my office is about 10-12 counts per minute. Outside I got 14-22 counts per minute and in the kitchen on granite counter top 22-24 counts per minute. Table spoon on NU-Salt gave me reading 28-36 cpm. So unit is working, however I only gave 3 stars, why!? My radiation detector dosen't have battery door!
I hope that I will be able to change my rating ones manufacturer sends me missing door.


After sending e-mail, I got prompt response from S.E. International that they will mail me battery door next day! That is a great customer service!
Detector is working great, I am pleased to report that there is no radiation in my neighborhood! My place is located about 30 miles from nuclear power plant, so I kind off worry about radiation.


I received missing battery door, great customer service. Radiation detector has been working continuously for three weeks showing radiation levels 12-20 counts per minute which is normal. Price off the product went up since I got it though, so the value is not that good anymore... LOL
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