International Medcom CRM-100 Digital Radiation Monitor
The International Medcom CRM-100 is a hand-held radiation detector that detects potentially harmful ionizing alpha and beta particles, and gamma and x-ray radiation, and features an accumulated total timer function, a Geiger-Mueller (G-M) tube, and LCD digital display of milliroentgens (mR) per hour (mR/hr), counts per minute (CPM), microSieverts (μSv) per hour (μSv/hr), or counts per second (CPS). This radiation detector has the ability to detect levels of the four main types of ionizing alpha and beta particles, and gamma rays and x-rays over automatic operational ranges. It is optimized to detect small changes (low levels) in radiation levels and to have high sensitivity to many common radionuclides.
The CRM-100 features a 4-digit LCD digital display that updates every three seconds. It displays current radiation level in choice of mR/hr, or CPM; or when SI (metric) units are selected, in μSv/hr, or CPS. The detector counts ionizing radiation changes at 3-second intervals. At low background levels, which are typical in a geographic area, the count update is the moving average for the most recent 30-second time period. A moving average helps smooth out short-term data fluctuations. The time period for the moving average decreases, as radiation levels increase. A red LED light flashes with each ionization event. The instrument has an accumulated total count and a timer function that provides total event count for a timed period (from one minute to 40 hours) to determine average CPM for higher accuracy. The radiation detector has an audio indicator with an internally mounted beeper that can be muted. Total timer, audio on/off and units of measurement are selected and displayed using the front-panel mode indicators.
This radiation detector has a halogen-quenched, Geiger-Mueller (G-M) tube with a pancake-shaped mica end window for sensing ionizing radiation. The unit is used for surveying levels of potentially harmful ionizing particles and rays in the environment such as in naturally occurring radioactive material (NORM) contamination, contamination detection of packages, and equipment, and in first responder, personal safety, educational, and ambient monitoring applications. It comes in a protective soft carrying case. The Radalert CRM 100 comes with a Certificate of Conformance. It cannot be returned.
| Sensor | Geiger-Mueller detector (LND712) with Mica end window 1.5 to 2.0 mg/cm2 density. |
| Side wall | 0.012†446 stainless steel |
| Operation ranges | 0.001 to 110 mR/hr, 0 to 350,000 CPM 0.01 to 1,100 μSv/hr, 0 to 3,500 CPS 0 to 9,999,000 total counts |
| Timer operation range | 1 minute to 40 hours |
| Calibration | Cesium 137 (gamma) |
| Sensitivity | 1000 CPM/mR/hr referenced to Cesium (Cs)137, detected through the end window |
| Accuracy | + or - 10% typical, + or -15% maximum (mR/hr and μSv/hr modes) |
| Radiation level display | 0.001 to 110 mR/hr, or 0 to 350,000 CPM |
| Radiation level display, SI (metric) units | 0.01 to 1100 microSieverts (μSv) per hour, or 0 to 3,500 counts per second (CPS) |
| Output | Stereo 3.5 mm jack for counts output to computers, data loggers, other CMOS-compatible devices, and headphones |
| Input | Mono 2.5mm jack provides electronic calibration input |
| Power | One 9-volt alkaline battery (not included) for approximately 2,160 hours of operation with continuous use in normal background. Minimum battery life is 625 hours at 1 mR per hour with beeper off |
| Dimensions | 150 x 80 x 30 mm/5.9 x 3.2 x 1.2 inches (H x W x D) |
| Weight | 225 g (8 oz.) with battery (not included) |
*(H is height, the vertical distance from the lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back.)
Radiation detectors, sometimes called Geiger counters or G-M counters, can detect a broad range of ionizing alpha and beta particles, and gamma and x-rays that may be emitting harmful levels of radiation. Many detectors sense ionizing radiation with an enclosed Geiger-Mueller (G-M) 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.
International Medcom, Inc. manufactures radiation detection instruments and systems for the health and safety, environmental protection, and education industries. The company was founded in 1986, and is headquartered in Sebastopol, CA. Many International Medcom products have International Organization for Standards (ISO) or Conformite Europeene (CE) certification.
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