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Kim, Kang, Rhee, Lim, Lee, Yi, Lee, Yang, Ro, and Jeong: Measurement of Electron Beam Output for the Prototype Compact Linac
Original Article

Progress in Medical Physics 2015;26(1):1-5.

Published online: 20 March 2015

DOI: https://doi.org/10.14316/pmp.2015.26.1.1

Measurement of Electron Beam Output for the Prototype Compact Linac

Sung-woo Kim∗, †, Sang Koo Kang∗, Dong Joo Rhee∗, Heuijin Lim∗, Manwoo Lee∗, Jungyu Yi∗, Mujin Lee∗, Kwangmo Yang∗, Tae Ik Ro†, Dong Hyeok Jeong∗

∗Research Center, Dongnam Inst. of Radiological & Medical Sciences, Busan, Korea

†Department of Material Physics, Dong-A University, Busan, Korea

Correspondence: Dong Hyeok Jeong(physics7@empas.com) Tel:82-51-720-5813, Fax:82-51-720-5826

Received 17 February 2015       Revised 9 March 2015       Accepted 13 March 2015

Copyright © 2015 Korean Society of Medical Physics

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The C-band compact linear accelerator (linac) is being developed at Dongnam Institute of radiological & Medical Sciences (DIRAMS) for medical and industrial applications. This paper was focused on the output measurement of the electron beam generated from the prototype electron linac. The dose rate was measured in unit of cGy/min per unit pulse frequency according to the IAEA TRS-398 protocol. Exradin-A10 Markus type plane parallel chamber used for the measurement was calibrated in terms of dose to water at the reference depth in water. The beam quality index () was determined by the radiochromic film with a solid water phantom approximately due to low energy electrons. As a result, the determined electron beam output was 17.0 cGy/(minㆍHz). The results were used to monitor the accelerator performance during the development procedure.

Keywords: Electron beam output, TRS-398 protocol, Prototype linac

References

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Fig. 1.
The configuration of instruments for the measurement of output with accelerating structure and irradiation head.
pmp-26-1f1.tif
Fig. 2.
Film dosimetry (left) and analysis of percentage depth dose curve (right) for electron beam from the prototype linac.
pmp-26-1f2.tif
Table 1.
Applied values for the determination of dose for the electron beam from prototype linac in water.
Items Values
Pulse frequency (f) 5 Hz (Maximum 250 Hz)
Measuring time 1 min
Zref 0.5 g/cm2
Mraw 1.438 nC±1.2%
kTP 1.012
kpol 0.999±1.4%
k3 1.023±1.1%
ND, w, Q0 59.6 cGy/nC
kQ, Q0 0.960
D(zref) 17.0 cGy/(minㆍHz)
D(zref)for maximum pulse f frequency 42.5 Gy/min
Table 2.
Estimated relative standard uncertainty for the output measurement.
Items Uncertainty (%) Note
Long term stability of dosimeter 0.4 TRS-398
Establishment of reference conditions 0.6 TRS-398
Mraw 0.5 A-type
kTP 0.1 Certificate
kpol 0.8 A-type
ks 0.6 A-type
ND, W, Q0 0.5 Certificate
kQ, Q0 1.7 TRS-398
D(zref) 2.2  
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