# Reference X-ray Irradiation System for Personal Dosimeter Testing and Calibration of Radiation Detector

• Accepted : 2019.05.13
• Published : 2019.06.30

#### Abstract

Background: In the calibration and testing laboratory of Korea Atomic Energy Research Institute, the old X-ray generator used for the production of reference X-ray fields was replaced with a new one. For this newly installed X-ray irradiation system, beam alignment as well as the verification of beam qualities was conducted. Materials and Methods: The existing X-ray generator, Phillips MG325, was replaced with YXLON Y.TU 320-D03 in order to generate reference X-ray fields. Theoretical calculations and Monte Carlo simulations were used to determine initial filter thickness. Beam alignment was performed in three steps to deliver a homogeneous radiation dosage to the target at different distances. Finally, the half-value layers were measured for different X-ray fields to verify beam qualities by using an ion chamber. Results and Discussion: Beam alignment was performed in three steps, and collimators and other components were arranged to maintain the uniformity of the mean air kerma rate within ${\pm}2.5%$ at the effective beam diameter of 28 cm. The beam quality was verified by using half-value layer measurement methods specified by American National Standard Institute (ANSI) N13.11-2009 and International Organization for Standardization (ISO)-4037. For each of the nine beams than can be generated by the new X-ray irradiation system, air kerma rates for X-ray fields of different beam qualifies were measured. The results showed that each air kerma rate and homogeneity coefficient of the first and second half-value layers were within ${\pm}5%$ of the recommended values in the standard documents. Conclusion: The results showed that the new X-ray irradiation system provides beam qualities that are as high as moderate beam qualities offered by National Institute of Standards and Technology in ANSI N13.11-2009 and those for narrow-spectrum series of ISO-4037.

#### Acknowledgement

Supported by : National Research Foundation of Korea (NRF), Korea Foundation Of Nuclear Safety (KoFONS)

#### References

1. International Organization for Standardization. X and gamma reference radiation for calibrating dosimeters and dose rate meters and for determining their response as a function of photon energy-Part 1: Radiation characteristics and production methods. ISO 4037-1. 1996;4-12.
2. American National Standard for Dosimetry. Personnel Dosimetry Performance-Criteria for Testing, ANSI/HPS N13.11-2009. 2009;13-18.
3. Korea Association of Standards & Testing Organizations. Standard Calibration Procedure of Personal Dosimeter for X-ray. KASTO 17-80102-397. 2017;1-10.
4. YXLON Technical data. Y.TU 320-D01/D03/D05.
5. National Institute of Standards and Technology. NIST measurement services: Calibration of X-ray and gamma-ray measuring instruments. NIST Special Publication. 2001;250-258.