-2-
คำสำคั
ญ :
กั
มมั
นตภาพรั
งสี
จำเพาะ ระบบวิ
เคราะห
แบบแกมมาสเปกโตรเมตรี
ปริ
มาณรั
งสี
ดู
ดกลื
น
ในอากาศ กั
มมั
นตภาพรั
งสี
สมมู
ลเรเดี
ยม ดั
ชนี
วั
ดความเสี่
ยงรั
งสี
ที่
ได
รั
บจากภายนอกร
างกาย
อั
ตราปริ
มาณรั
งสี
ยั
งผลในอากาศต
อป
Abstract
Specific activities of natural radionuclides in 60 soil samples collected from Thaksin University
Songkhla Campus Muang district Songkhla province (30 soil samples) and Phattalung Campus
Pa-Phayom district Phattalung province (30 soil samples), have been studied and presented. The specific
activities of
226
Ra,
232
Th and
40
K were determined in all soil samples (60 samples) using high
purity germanium detector (HPGe) and gamma ray spectrometry analysis system at Thailand
Nuclear Institute of Technology (Public Organization), TNIT. The specific activities of soil samples
Thaksin University Songkhla Campus ranges from 8.90 – 42.08 Bq/kg for
226
Ra, 17.41– 146.24
Bq/kg for
232
Th and 443.05 – 1455.84 Bq/kg for
40
K with mean values of 24.43 ± 1.35, 55.89 ± 4.56
and 949.64 ± 26.03 Bq/kg, respectively. The specific activities of soil samples Thaksin University
Phattalung Campus ranges from 5.97 – 34.36 Bq/kg for
226
Ra, 14.49 – 123.95 Bq/kg for
232
Th and
46.13 – 1000.57 Bq/kg for
40
K with mean values of 18.60 ± 0.92, 67.24 ± 4.61 and 298.35 ± 14.58 Bq/kg,
respectively. The results were compared with the OAP data in annual reports, Thailand and worldwide
research reports. Moreover, absorbed dose rates in air (D), Radium equivalent activities (Ra
eq
) and
external hazard index (H
ex
) were calculated using the calculated data in soil samples collected from
both Songkhla and Phattalung campuses. It was found that of all of these samples have a mean value
of radium equivalent activities lower than the limit set in the OECD report (<370 Bq/kg). Radiation
hazard indices (H
ex
) were also calculated and found lower than the safty limits (<1.0). Moreover,
the annual effective dose rate in air of all soil samples were also assessed and compared with the
recommended value (100 μSv/y).
Keywords :
Specific activity; Gamma ray spectrometry analysis system; Absorbed dose rates in air ;
Radium equivalent activity; Radiation hazard index; Annual effective dose rate in air
