Can the palmRAD 907 detect Radon by looking at alpha or gamma? There are significant advantages in being able to effectively detect alpha radiation from Radon. To explain, in the uranium series (U238), radon (Rn222) is in the chain with a 3.8-day half-life. In the thorium series (Th232), radon (Rn220) exists with a half-life of about 56 seconds. In the actinium series (U235), radon (Rn219) has a 3.96 second half-life. Only Rn219 has gamma lines that can be easily measured - but all radon has well defined alpha lines and can all be measured with the thin window of the palmRAD and close placement of the GM tube. (Back)
Can I store the palmRAD with batteries? No. If you plan to shelf the product, remove the batteries to avoid corrosion. (Back)
Is the palmRAD calibrated to NIST traceable standards? Yes, you may have your unit calibrated to NIST traceable standards, and BNC will provide the test data and a certificate. (Back)
At what decibel level does the palmRAD alarm sound? The dB levels on the alarm and LED chirps for Model 907 is 75 dB at 12 inches (3kHz). (Back)
What is the maximum operating temperature (degrees C) for the palmRAD meters? Maximum operating temperature of our detectors are -10 to +50 C (Back)
Do your instruments measure x-rays? Our Geiger counters detect x-rays, but may not be accurate in measuring the dose rate. This is because an x-ray is usually a short concentrated burst of radiation. A Geiger counter measures by detecting individual ionizing events in its Geiger tube. The events during the X-ray usually occur so fast that the instrument cannot detect all of them, giving a reading that does not reflect the full amount of radiation. For a true dose rate, an ionization chamber would be required. Medical and dental x-ray machines sometimes have "scatter," or leakage in directions other than the target. Inadequate shielding can cause this scatter to reach personnel, resulting in unnecessary exposure. To screen for scatter, you can place PalmRAD 907 or Geiger in a location you want to test while the x-ray machine is activated. If there is scatter, if the instrument is in Audio mode, you will hear a rapid burst of chirps, or clicking, and it will produce a higher-than-normal reading. Keep in mind that the reading, while a reliable indicator of scatter, is not an accurate measurement. (Back)
What instrument do you recommend for use in medical or research facilities where radioactive substances are in use? The PalmRAD 907 was specifically designed for use in laboratories and medical facilities. It uses a "pancake" detector, the type that is recommended by regulatory agencies and health physicists for surface contamination measurements of a number of commonly-used radionuclides, including C-14, P-32, S-35, Cr-51, I-125, Na-22, Cl-36, Ca-45, Co-57, Zn-65, Tc-99m, In-111, and Tl-201. (For the Cl-36 and Ca-45, the measurement should be made using the PalmRAD’s wipe test attachment.) (Back)
How often do your instruments need to be calibrated? Some Geiger counters, especially older designs, require regular calibration to ensure that their readings are accurate. Our instruments incorporate innovative modern design techniques and high-quality components. We have found that the palmRAD line of instruments maintain their original calibrations remarkably well. Some facilities require calibration certificates or annual calibration with an NIST-traceable source. Our instruments are calibrated electronically after manufacturing, and we can provide an electronic calibration certificate at no additional cost if it is requested at the time the order is placed. If you require NIST-traceable calibration, we can provide it at additional cost at the time the order is placed, and we can refer you to a laboratory that offers calibration services for annual calibrations. If your instrument is for educational or hobby use, you probably do not need to calibrate it on a regular basis, but you may want to check it periodically against a known source of radioactivity to assure yourself that it is working properly. If you use the instrument professionally in an environment that has radioactive materials, you can use a calibrated check source periodically for the same purpose. (Back)
Do your instruments detect radon? How would I use one for this purpose? There are differences of opinion on the suitability of Geiger counters for detecting radon. While it’s true that the PalmRAD 907 does not specifically measure radon gas, experiments with the PalmRAD in a controlled environment with different levels of radon gas indicated that the average counts per minute did rise and fall with radon concentrations. The radiation detected is a combination of the emissions from radon and its "daughters" (decay products). The results of the experiments showed an almost linear increase of CPM (counts per minute) in relation to increased radon concentration; from 17 CPM at 0 radon concentration to 33 CPM at a concentration of 65 pCi/l. At 4-5 pCi/l, the increase was 1 CPM. The PalmRAD907, though it has not been tested with radon, should be more effective, as it has a higher sensitivity to alpha and beta radiation. We do not recommend the PalmRAD 907 as an alternative to EPA-approved carbon canisters or other standard methods of testing for radon. If you want to use the PalmRAD 907 for experimental, educational, or screening purposes in regards to radon, the following guidelines may be helpful. The most likely entrance points for radon in homes or other buildings are cracks or openings in the floor around pipes or conduit, unsealed wall-floor joints, and underground hollow block walls. Dirt floors in basements are particularly vulnerable. Unventilated basements or closets normally have higher levels of radon than well-ventilated areas. Before you screen for radon, you should establish baseline measurements; for example, determine the background level in a location outdoors three feet above the ground and in a location in a place in the house not likely to have radon accumulation. It is best to accumulate the baseline counts for 12 hours as described below. To screen for radon, place the instrument on the floor near any suspected entrance point. For best results, keep air exchanges between indoors and outdoors at a minimum for 12 hours before and during the test. Set the display to Total and accumulate the counts for 12 hours in each location. Divide the total count for the period by the exact number of minutes to get the average CPM. If the 12-hour average CPM in your home is more than 1 CPM higher than outdoors, you may want to do further testing for radon using carbon canisters or other EPA-approved methods. Another way of screening for radon is by checking the air particulates, or dust. Several radon daughters, which account for much of the radiation produced by radon, are negatively charged and attach themselves to the dust. You can obtain accumulated dust by wiping a television or computer monitor screen with a piece of tissue paper (the CRTs are positively charged and this specifically attracts the negatively-charged particles) or by attaching filter paper or medical gauze to a vacuum cleaner nozzle and running it for half an hour. You can also measure the dust on an air-conditioning, heating system, or air-purifying filter. A high measurement from concentrated air particulates is an indication of the presence of radon. Keep in mind that since the radon daughters are concentrated, high readings are not unusual if any radon gas is present. (Back)
Do your instruments measure microwaves? Radiation from cellular phones? Power lines? Our instruments measure ionizing, or nuclear, radiation. Radiation from microwave ovens, cellular phones, power lines, and electric appliances is non-ionizing electromagnetic radiation, which our instruments do not detect. (Back)
How would I measure radiation in food? Accurate measurement of radiation in food requires a multi-channel analyzer and a special oven for ashing the food to concentrate the radioactivity. Our instruments have been used for experimental, educational, and screening purposes in checking food. Measuring radiation in food is tricky. Naturally occurring radiation in potassium-rich food (such as bananas, when dried into banana chips, and salt substitutes) from Potassium 40 can easily be detected with the PalmRAD 907. In the case of fallout from nuclear testing or accidents (such as Chernobyl), you would be looking mostly for Strontium 90, Cesium 137, and possibly Plutonium 239. Of our instruments, the PalmRAD 907 is the best for this application because of its higher sensitivity. The PalmRAD’s efficiency for Sr90 and Cs137 beta is good, and it does detect the Cs137 gamma. It does detect Pu239, but Pu239 can have health effects at very low concentrations, which can be difficult to detect with any instrument. Before you screen for radiation in food, you should establish a baseline measurement in the same location where you plan to test the food. It is best to accumulate the baseline counts for 12 hours as described below. When you measure, you should put the mica window of the instrument directly over the food you are measuring, as close as possible. In the case of milk or other liquids, fill a container very close to the top so you can measure directly, without the glass in the way. If all your milk is from the same source, you might want to boil or evaporate some to concentrate it, then take a measurement from that. Set the display to Total and accumulate the counts for 12 hours in each location. Divide the total count for the period by the exact number of minutes to get the average CPM. (Back)
How do you determine the MDA (minimum detectable activity) of beta radiation in a contaminated sample? You need to know the efficiency of the detector for the particular radionuclide, then you need to determine the sampling time to obtain the (statistical) level of confidence that you want (for example, 2 sigma). You must also consider the detector geometry in relationship to the source; for example, if you are measuring on a flat surface, you detect only the radiation that decays in the direction of the detector; so, using a 1000 DPM point source with 100% detection efficiency, you would detect approximately 0 DPM. Using the PalmRAD 907 in the Total mode (accumulated counts) greatly enhances the sensitivity by providing a longer sampling period. (Back)
