Characterization tests of a new parallel plate ionization chamber for use in electron beams

• An ionization chamber was developed to be used in radiotherapy electron beams.
• The ionization chamber was submitted to several characterization tests.
• The test results showed values within the international standard limits.

Linear accelerators with electron beams are used in several Brazilian hospitals. Consequently, there is an increasing demand for parallel-plate ionization chambers, to be utilized for dosimetry of electron beams. In Brazil, the commercial ionization chambers utilized are imported. The ionization chambers have usually a simple construction, using different materials and geometries. A homemade ionization chamber was developed to be used in electron beams of linear accelerator. The ionization chamber body is made of acrylic and the collecting electrode is painted with graphite powder mixed with nail polish. Several tests were applied, and the results showed values better than the limits established by the international recommendations, except for the polarity effect test, but the response of the developed ionization chamber, for this test, is similar in relation to the response of other commercial ionization chambers from the literature.