New Application Note on Wipe Testing Published
December 17, 2025
Hidex offers several instruments suitable for measuring alpha, beta and gamma radionuclides in various wipe test applications.
Wipe tests, also called swipe or smear tests, are a crucial method for monitoring surface contamination in environments where radioactive materials are handled. By using a moistened, absorbent material to wipe surfaces, this technique helps detect traces of radioactive contamination that may not be visible. The collected samples are then analysed using radiation detectors, such as liquid scintillation counters or gamma counters, to quantify the level of contamination in the workplace.
When are wipe tests used for contamination monitoring?
Typically, wipe tests are used to monitor contamination from low-energy beta-emitting radionuclides such as tritium (³H), carbon-14 (¹⁴C), and sulfur-35 (³⁵S), but they can also be employed to detect alpha contamination. For weak beta-emitters like tritium, wipe testing followed by liquid scintillation counting (LSC) is often the only practical option for monitoring their presence. Hidex offers several instruments suitable for measuring alpha, beta and gamma radionuclides in various wipe test applications.
How to perform swipe tests?
Wipe Materials: Filter papers are commonly used due to their high absorption capacity, cost-effectiveness, and compatibility with various radiation analysis methods. Glass fiber filters are excellent wipe materials for both alpha and beta contamination, offering high collection efficiency and reliable activity recovery.
Pre-moistened or Dry Wipes: Wipes can be used either dry or pre-moistened, often with distilled water or a mild detergent, depending on the type of contamination and the surface characteristics. Pre-moistened wipes typically improve the pick-up efficiency of the wipe. Typically, the standard area for a wipe test is 100 cm².
What is the significance of wipe testing?
Routine wipe testing plays a vital role in maintaining safety standards, ensuring regulatory compliance, and protecting personnel and the environment from potential exposure to harmful radiation. Wipe testing is widely used for detecting leaks in sealed radioactive sources, ensuring they remain intact and do not release radioactive contamination.
Surface contamination activity limits vary depending on the type of radioactive material, regulatory body, and the specific application environment, for example, laboratories, medical facilities or nuclear power plants. These limits are set to ensure safety for workers and the public and are generally expressed in terms of becquerels per square centimeter (Bq/cm²) or disintegrations per minute per square centimeter (dpm/cm²). The recovery of radioactivity from a wiped object depends on several factors: the properties of the surface, the radioactive compound, and the characteristics of the wipe material.
What information does the application note include?
The wipe test application note provides a detailed overview of how wipe testing can be performed. It provides a step-by-step of the process, starting from sample preparation options, performing the sampling, which instruments support wipe testing, surface contamination calculations for the radionuclides, and standard activity limits set by regulatory bodies.
In other words, the application note guides the user through the know-hows of wipe testing and can be found simply from our website. The guide has been prepared, keeping in mind, that wipe testing is a key application in radiation protection and workplace contamination monitoring and aims to address the most frequently asked queries on the topic. You can contact Hidex experts if you have further questions or wish to discuss with our experts.