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Radalert 100X Geiger Counter

2.00 LBS
  • Product Description

    The  successor to the proven and popular Radalert 50, the Radalert 100X is a digital pocket Geiger counter designed for general purpose monitoring  of radioactivity.

    It detects Alpha, Beta, Gamma and X-radiation, visually  shown on a highly accurate digital display with readings in your choice  of both CPM (to 110,000 counts per minute) and mR/hr (up to 110 mR/hr),  or switchable to the international standard of µSv/hr (up to  1,100 uSv/hr).




    A red LED blinks and a beeper  chirps with each radiation count.  The audio chirp can be turned off.

    The Radalert  100X derives its name  from an audible alert that sounds when the radiation reaches a  user-adjustable level.  Play this sound file.  The picture at right shows that adjustment on the  top of the unit, next to the screened open end window over the Geiger-Mueller  tube.


    The Radalert 100 also can be set  for a Total Count , which will accumulate the radiation  counts over time.  This is a useful feature especially for establishing  your background radiation level.   As an example, you can set the unit to  Total, and after say 10 minutes, divide the Total Count value by 10 to arrive at  your background radiation in CPM.

    This unit also has a Data Output port to record counts on a computer or data logger, as shown in the picture at right. Select the navigation button above or click on this link for more on the on data output, and the  optional Software accessories.   Also note the same port Audio out for external sound.

    The Radalert 100 runs on a single 9 volt  alkaline battery (included) which will last up to three months on continuous use at background levels.

    The Radalert also comes with a  padded nylon carrying case with belt loop, shown at left.

    The Radalert also comes with perhaps the best Operation Manual of  any Geiger counter in our class - in printed, booklet form, and very user  friendly and thorough.

    Scroll down for detailed Specifications on the Radalert 100X.

    The Radalert  100 is a very popular unit.  If you want an all-around  excellent Pocket Geiger Counter with a digital readout versus an analog meter, along with a user  adjusted audible  alert, and/or desire a data port,  we recommend this unit.

    The Radalert 100X typically ships within 1 business day.


    Specifications for the Radalert  100:



    Halogen-quenched, long thin cylindrical Geiger-Mueller tube (LND712) with side wall of .012" #446 stainless steel, and with thin mica end window

    Window Size

    1.5 to 2.0 mg/cm²     thick;

    Radiation Detected Alpha, Beta, Gamma, X-ray
    Sensitivity Detects alpha down to 2.5 MeV; efficiency at 3.6 MeV > 80%
      Detects beta at 50 keV w/35% efficiency, at 150 keV w/75%
      Detects gamma and X rays down to 10 keV thru window, 40 keV minimum through case; gamma sensitivity is 1,000 CPM/mR/hr     referenced to Cs-137
      Normal background is approximately 10 to 20 CPM


    ± 10%typical;±15% max.

    Operating Ranges

    .001 to 110 mR/hr; .01 to 1,100 µSv/hr; 0 to 350,000 CPM; 0 to 3,500 CPS; Total from 1 to 9,999,000 counts; Timer: up to 40 hours

    Anti-Saturation "Jam" protection allows readout out to hold at full scale in high radiation fields
    Indicators LED display, red LED count light, audible beeper for count rate, and audible alert
    Display 4-digit liquid crystal display with mode indicators; updates every 3     seconds
    Count Light Red LED flashes with each count
    Beeper Chirps for each count (can be muted)
    Alert User-adjustable alert level to 50 mR/hr & 160,000 CPM, set using three buttons - default is 100 CPM


    At factory to NBS standard Cesium 137 gamma source

    Temperatur Range -10 deg. to +50 deg. C, 14 deg. to 122 deg. F

    Power Required

    One 9-volt alkaline battery (included in price of the unit)

    Battery Life

    About  2,160 hours at nomal background  radiation; about  625 hours at 1 mR/hr with beeper off


    225 grams (8 oz.) including battery


    150 x 80 x 30 mm (5.9 x 3.2 x 1.2 in.)

    Output Port Stereo 3.5 mm jack on side sends counts to computers, data loggers, other CMOS-compatible devices, and headphones
    Input Port Mono 2.5 mm jack provides electronic calibration input
    Options Computer cable and software (See Software)
    Warranty Two year limited on instrument, 1 year on Geiger-Mueller tube; includes CE mark

    Country of Make



    Click on this link for the:

    Radalert 100X  Operating Manual



    Radalert 100X™ Quick Start Guide

    Thank you for purchasing this high quality Geiger Counter. With proper care  it will provide you many years of reliable performance.

    For complete operating instructions please download the complete manual at: Product Manuals

    The instrument is ready to use when it comes out of the box.  A 9 volt  alkaline battery is already installed. This battery will operate the instrument  continuously for at least 7 weeks at normal background radiation levels. A low  battery indicator will appear on the LCD when the battery needs changing.

    Turn the instrument ON. You will now see the red LED flash occasionally,  indicating radiation is being detected. In AUDIO mode you will also hear a beep  each time radioactivity is detected. Put the mode switch (above the OFF-ON-AUDIO  switch) in the CPM (Counts per Minute) Mode. Normal background radiation from  outer space and the earth will always be present at the rate of 10 to 75 CPM  (Counts per Minute). The count rate will vary with altitude and mineral content  in the earth.

    The detector, a high quality Geiger Mueller tube, is locate behind the screen  on the top of the instrument. Alpha and beta radiation can be detected through  the screen. The window of the detector is made of mica and is delicate, so  please handle with care.

    When you turn the instrument on you will see the LED blink when a radioactive  “event” is detected. In Audio mode you will also hear each event. Your ear will  be able to detect changes in the count rate as you move closer to, or away from,  radioactive sources.

    For measuring gamma radiation use the mR/hr or µSv/hr modes of operation. The  instrument is shipped from the factory in mR/hr mode. To switch to SI units (µSv/hr),  please us the Utility Menu (more on this below). The instrument is calibrated  for gamma radiation from Cesium 137.

    For measuring mixed alpha, beta and gamma radiation, use the CPM (Counts per  Minute) mode. This will give you a relative reading of all radiation combined.  For complete specifications on the instrument’s sensitivity to various types of  radiation please go to Specifications.

    To detect subtle changes in radiation levels, use the Total/Timer function.  The + and – buttons allow you to set a period of time for measuring radioactive  events. Push the Set button to start counting. Counting for long periods, 5  hours or more, will provide best results. Compare total count readings from  location to location, or find a stable background level at one location and then  compare results with various sources of food or household items.

    Switching between mR/hr and µSv/hr: Utility Menu is accessed  by pushing the + button while turning the instrument on. The instrument will  display “Menu 1.” Press the + button again to advance to “Menu 2.” Press “Set”  to enter Menu 2. You can now scroll between mR/hr and µSv/hr. Select the units  you would like to use and then press “Set.” Turn the instrument off and then on  again to activate the new setting.

    To Set the Alert feature

    While in a dose mode (CPM, CPS, mR/hr or µSv/hr), Press the “Set” button on  the end panel. The numeric display shows the current alert level for the current  setting.  The radiation symbol and SET icons will also be displayed.  Use the +  and – buttons to adjust the level up and down.  When the desired alert level is  displayed, press the “Set” button again to save the level and continue in Alert  mode (the SET icon is no longer displayed).  The radiation symbol is displayed  to show that the instrument is in Alert mode.  To turn off Alert mode, press the  “Set” button once.

    What Radiation Level is Normal?

    Radiation levels vary with altitude (usually higher as elevation level goes  up), and with soil mineral content, and other factors. In an airplane, radiation  levels can get quite high due to cosmic rays from outer space that typically are  shielded by the upper atmosphere. Radiation levels on ground at sea level are  typically in the range of 10 to 50 CPM, 0.01 to 0.05 mR/hr, 0.1 to 0.5 µSv/hr.  Radioactive materials in the earth, natural or man-made, will contribute to  higher levels.


    This product is warranted to the original owner to be free from defects in  materials and workmanship for two year from the date of purchase, except for the  Geiger tube, which is warranted for one year. The battery is not included in the  warranty. IMI will repair or replace your instrument if it fails to operate  properly with this warranty period provided it has not been subjected to misuse,  abuse, or neglect. Modification or repair of this instrument by anyone other  than IMI or their approved repair facility voids this warranty. IMI is not  responsible for incidental or consequential damages arising from the use of this  instrument.

    Contamination of the instrument with radioactive materials voids this  warranty.

    Contaminated instruments will not be accepted for servicing at our repair  facility.

    The user is responsible for determining the usefulness of this product for  his or her application.

    *Specifications Subject to Change Without  Notice

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