Whole-body dosimetry

Film dosimeter - your dosimeter for photon fields

Our film badges are the perfect dosimeters in almost all application areas of the whole-body dosimetry in photon fields. It is inexpensive and reliable!

This is an established method for measuring the personal dose equivalent by X-ray and gamma radiation. Our film badges are best suited for the official surveillance of the personal dose. Due to measurement methods developed according to the state-of-the-art in science and technology, our film badges can cover a large energy range. 

Short description

The film badge is a dosimeter for measuring the dose equivalent by X-ray, gamma and electron radiation in the whole-body and area dosimetry.

The dosimeter probe consists of a Luran® cassette and a numbered measurement film package that contains two different sensitive measurement films (monitoring AGFA D10/D2 measurement films). Housing and cover of the cassette enclose the film holder and contain different filters.     

The cassette, which is available in blue, red, yellow and green, is equipped with a clip for fastening.

A film holder, similar to the one used in the dental care for intra-oral X-ray films is inserted in the cassette. This film holder contains two films of different sensitivities that are shielded by black paper against the influence of light.

Our film badge dosimeter is an official personal dosimeter approved by virtue of its construction by the Physikalisch-Technische Bundesanstalt (PTB).   

Unlike other whole-body dosimeters, the film dosimetry is an imaging, multiple readable measurement technique. In addition, films can provide information on the exposure conditions such as the direction of the incident radiation or suspected contamination.

Transparent cassette cover, cassette bottom, film, assembling of a film dosimeter

Source: Helmholtz Zentrum München

Transparent cassette cover, cassette bottom, film, assembling of a film dosimeter

Source: Helmholtz Zentrum München

Functioning and dose determination

Ionizing radiation (X-rays, gamma, beta or electron radiation) is attenuated on its way to the measurement film through different filters in the plastic cassette. Complex mathematical algorithms calculate dose and energy field using the optical densities behind these filters.

Under the effect of the above mentioned radiation, the resulting secondary electrons cause blackening of a photographic emulsion. The blackening is a measure unit for the emitted dose. The strong energy dependence of the film emulsion is compensated by absorption filters of different thicknesses and different materials.

The blackening of the film is measured by densitometry at the monitoring service. From the blackening behind the single absorption filters, the individual dose is determined according to the linear combination method or the analytical filter method by means of previously determined calibration and correction factors.

Wearing options

The measuring film holder for the film badge dosimeter of type S is issued by the monitoring service for a wearing period (usually one month) and assigned to the person associated with the number imprinted on the film. Place the dose measurement film in the separately available and reusable holder and wear the dosimeter during the monitoring period at the upper part of the trunk (chest area).

Wearing options of the dosimeter around the chest or trunk

Source: Helmholtz Zentrum München

Wearing options of the dosimeter around the chest or trunk

Source: Helmholtz Zentrum München

Operating instructions

The dosimeter must be positioned towards the expected radiation source in such a way that the radiation optimally reaches the probe level perpendicularly from the front, always maintaining an incidence angle of +60 to -60 degrees.   

The dosimeter is suitable for use at ambient temperatures of 0° C to +40° C and a relative humidity of 10% to 90%. It should not be exposed to direct sunlight radiation over 1000 W / m² or mechanical shocks over 4900 m / s ². If necessary, the cassette (but not the measurement film holder) can be cleaned with a damp cloth.

Energy range and measuring range

Energy rangeLimits of detection Nominal operating range
in accordance with PTB requirements
Photons5 keV - 9 MeV20 keV - 4,5 MeV
Beta> 300 keV-
Dose measuring rangeLimits of detectionNominal operating range
in accordance with PTB requirements
Photons at 35 keV0,01 mSv - 1 Sv0,2 mSv - 1 Sv
Photons at 1,3 MeV0,1 mSv - 10 Sv0,2 mSv - 1 Sv
Beta0,1 mSv - 1 Sv-

Additional measurement data

In contrast to all other currently used passive personal dosimeters, film bagdes provide additional information on exposure conditions, which leads to a considerable improvement of radiation protection control. Routinely (i.e., within the normal evaluation process), the mean photon energy and the direction of the incident radiation can be determined with the film badge.

A lateral irradiation at an angle of 60-120 degrees (typically caused by a faulty wearing of the dosimeter) generally leads to an overestimation of the dose. The additional information on the direction of the incident radiation, however, allows in this case a more realistic dose assessment within the evaluation of the measurement results.

Backward radiation - i.e. transmission through the body by proper wearing of the dosimeter - can also be routinely detected, and it provides valuable information for the evaluation of the measurement results. With those types of dosimeters, which do not allow the detection of backward radiation, the supposedly low dose values can not be estimated correctly, and thus, limit value exceedances can remain undetected!

A "one-step", i.e. possibly deliberate exposure is also visible, since in such a case, the shadows of the absorption filters within the cassette are sharply imaged on the measurement films. Typically, due to diffusely occurring scattered radiation or a movement of the dosimeter in front of the radiation source, the filters within the cassette are reproduced with soft edges on the measurement films.  

With film badges, it is possible to detect whether they are properly worn on the body during exposure or whether, perhaps, they are irradiated free-in-air. In such a case, the radiation fraction, which is scattered back from the body and which can be determined during evaluation, is absent.  

A qualitative indication of radioactive contaminations can also be determined. This is particularly important when dealing with sealed radioactive substances, because, per dosimeter, detection of leaks is possible. In other dosimeters, which do not allow detection of radioactive contaminations, the lack of detection usually leads to false, excessive dose values.

Film dosimeter exposed to direct radiation

Source: Helmholtz Zentrum München

Film dosimeter exposed to direct radiation

Source: Helmholtz Zentrum München

More information can be found in our flyers which are available for download