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Dose Profile Measurements with a Liquid-Filled Ionization Chamber Array in An Ultra-High-Energy Lead Beam of 150 GeV/n

V Wyrwoll1,2,3*, B Delfs2 , M Lapp4 , D Poppinga4 , H Looe2 , R Garcia Alia1 , B Poppe2 , (1) CERN, Geneve, Switzerland, (2) University Clinic for Medical Radiation Physics, Medical Campus Pius Hospital, Carl von Ossietzky University, Oldenburg, Germany, (3) University of Oslo, Oslo, Norway, (4) PTW Freiburg, Freiburg, Germany


(Wednesday, 7/17/2019) 10:00 AM - 10:30 AM

Room: Exhibit Hall | Forum 6

Purpose: Ultra-high energy ion beams (UHE) are of interest for testing radiation hardness of electronic devices, characterizing and measuring of LET spectra as well as for radiation protection issues of manned and unmanned space missions. In this study, the possibility of on-line monitoring of an UHE beam using a commercial liquid filled ionization chamber array are evaluated.

Methods: Measurements have been performed in the North-Experimental Area at CERN (Switzerland) utilizing a 150 GeV/n lead beam. In this facility, two-dimensional dose profiles are only available through Gafchromic film measurements which have to be irradiated over a prolonged period of time and require extensive post processing, leading to the need of an on-line beam monitoring. Therefore, the two�dimensional liquid filled ionization chamber array Octavius 1000SRS (PTW-Freiburg, Germany) is a promising device since it can be used to measure two-dimensional dose maps with high spatial resolution and minimal energy dependence and can be read out during the irradiation. It was placed at various positions in the UHE beam line and was irradiated with the 150 GeV/n lead ions. Film measurements, carried out as a reference using Gafchromic XR-QA2 films (Ashland Specialty Ingredients, Bridgewater, NJ) were compared to the array measurement.

Results: The Octavius 1000SRS performance has been excellent while exposed to the UHE heavy ion radiation environment, on-line detecting even single ion spills. The measured two-dimensional dose profiles characterizing the lead beam in size and shape show good agreement to the film measurement. Significant divergence of the beam could be ruled out by determining the beam size at different measurement positions.

Conclusion: This study shows the applicability of the Octavius 1000SRS as an on-line beam profile monitor in a heavy ion beam which represents an excellent opportunity for live beam observation for the user in similar facilities.


Not Applicable / None Entered.


TH- Radiation dose measurement devices: Multi-dimensional diode/chamber arrays

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