Background: Heavy ion track is one kind of very important information for diotherapy study. Purpose: The aim is to study the spatial distribution of the heavy ions energy deposition when they pass through certain matter

especially the biological tissue. Methods: A heavy ion track imaging detector system which is based on gas avalanche chamber and charge-coupled device (CCD) optical readout system was developed. Preliminary experimental test was performed

in which α particle radiated from 239Pu was used as the incident particle. Results: α particle track imaging was achieved successfully. It is found that α particle track is closely related to the gas pressure in the avalanche chamber and the exposure time of the CCD camera. According to analyzing the data of α particle track under the condition of gas pressure equivalent to 15 hPa and exposure time equivalent to 10 s

it is proved that the track structure is axisymmetric. With incident depth increasing

the track spread decreases gradually

and the image points density increases. Conclusion: We developed the heavy ion track imaging detector system which can achieve α particle track imaging successfully

and some preliminary law of charged particle track can be found. Abstract