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IAEA/RGU-1 ¨³ IAEA/RGTh-1) °ŠšªŠ„µ¦¡¨´ ŠŠµœž¦¤µ–¼¦³®ªnµŠž¦³Áš«(International Atomic Energy
Agency : IAEA)Ž¹ÉŠÅ—o¦´‡ªµ¤°œ»Á‡¦µ³®r‹µ„£µ‡ª·µ¢d ·„r ‡–³ª·š¥µ«µ˜¦r ¤®µª·š¥µ¨´¥Š ¨µœ‡¦·œš¦r ª·š¥µ
Á ˜®µ—Ä®n Ĝ„µ¦Áž¦¸ ¥Áš¸¥Â¨³ª·Á‡¦µ³®r®µž¦·¤µ–„´¤¤´œ˜£µ¡‹Î µÁ¡µ³ °Šœ·ªÅ‡¨—r „´¤¤´œ˜¦´Š¸Äœ˜´ª°¥n µŠ—·œ
š´Ê Š 160 ˜´ª°¥nµŠ nªœ„µ¦´œš¹„¨³ª·Á‡¦µ³®r¡¸ ‡¡¨´ŠŠµœ(photo peak)‹µ„Áž„˜¦´ ¤¡¨´ŠŠµœ °Š¦´Š¸Â„¤¤µ‹µ„œ·ª
Ҩ—r¦´Š¸š¸É ˜o°Š„µ¦‹³Äo ަ„¦¤‡°¤¡·ªÁ˜°¦r εÁ¦È‹¦¼ž (GENNIE 2000) °Š¦·¬´ š Canberra Industries 宦´ 
Ĝ„µ¦ª·Á‡¦µ³®r‡nµ„´¤¤´ œ˜£µ¡‹ÎµÁ¡µ³ °Šœ· ªÅ‡¨—r¦´Š¸›¦¦¤µ˜· œ· — 226 Ra ¨³ 232 Th Ĝ˜´ª°¥nµŠ—·œš´ÊŠ 160
˜´ª°¥nµŠ čo ª·›¸„µ¦˜¦ª‹ª´—¡¨´ŠŠµœ¦´ Š¸Â„¤¤µ‹µ„œ·ªÅ‡¨—r„´¤¤´œ˜¦´Š¸¦»nœ¨¼„š¸É°¥¼nĜ°œ»„¦¤Á—¸¥ª„´ œÂ¨³Á„·—¤—» ¨
šµŠ„´ ¤¤´œ˜¦´Š¸ ×¥š¸É‡nµ„´¤¤´œ˜£µ¡‹ÎµÁ¡µ³ °Š 226Ra µ¤µ¦™‡Îµœª–Å—o ‹µ„¡ºÊœš¸ÉĘo¡¸‡¡¨´ŠŠµœ °Š¦´Š¸Â„¤¤µ
°Š 214Pb š¸É¡¨´ŠŠµœ 351.9 keV 宦´‡nµ„´¤¤´œ˜£µ¡‹ÎµÁ¡µ³ °Š 232Th µ¤µ¦™‡Îµœª–Å—o‹µ„¡ºÊœš¸ÉĘo¡¸ ‡
¡¨´ŠŠµœ °Š¦´Š¸Â„¤¤µ °Š 208Tl š¸É¡¨´ ŠŠµœ 583.2 keV nªœ‡nµ„´¤¤´œ˜£µ¡‹ÎµÁ¡µ³ °Š 40K µ¤µ¦™‡Îµœª–Å—o ‹µ„
¡ºÊ œš¸ÉĘo¡¸‡¡¨´ŠŠµœ °Š¦´Š¸Â„¤¤µ °Š˜´ªÁ°Šš¸É¡¨´ ŠŠµœ 1460.8 keV ¨³‡nµ„´¤¤´œ˜£µ¡‹ÎµÁ¡µ³ °Š 137Cs µ¤µ¦™
‡Îµœª–Å—o‹µ„¡ºÊœš¸ÉĘo¡¸ ‡¡¨´ŠŠµœ °Š¦´ Š¸Â„¤¤µ °Š˜´ªÁ°Šš¸É¡¨´ŠŠµœ 661.7 keV Án œ„´œ nªœÁª¨µš¸É čoĜ„µ¦
˜¦ª‹ª´—ž¦·¤µ–¦´Š¸Â„¤¤µÄœš»„˜´ ª°¥nµŠ—·œ¤¸ ‡nµÁšnµ„´œ‡º° 10,800 ª· œµš¸ ®¦º° ž¦³¤µ– 3 ´ÉªÃ¤Š ®¨´ Š‹µ„œ´Êœ ‹³
œÎµ‡nµ„´¤¤´œ˜£µ¡‹ÎµÁ¡µ³ °Š 226Ra 232Th ¨³ 40K š¸É ˜¦ª‹ª´—Å—oœ¸Ê¤µ‡Îµœª–®µ‡nµ°´˜¦µž¦·¤µ–¦´Š¸Â„¤¤µ—¼—„¨ºœ
(gamma-absorbed dose rate: D) —´ Š¤„µ¦˜n°Åžœ¸Ê(Singh et al., 2005)
D = (0.461CRa + 0.623CTh + 0.0414CK) …..…………………………..(1)
×¥š¸É D ‡º° ‡n µ°´˜¦µž¦· ¤µ–¦´Š¸Â„¤¤µ—¼—„¨ºœ Ĝ®œn ª¥ °Š (nGy/h)
C Ra ‡º° ‡nµ„´¤¤´œ˜£µ¡‹Î µÁ¡µ³ °Š 226 Ra Ĝ®œnª¥ °Š (Bq/kg)
C Th ‡º° ‡nµ„´¤¤´œ˜£µ¡‹Î µÁ¡µ³ °Š 232 Th Ĝ®œnª¥ °Š (Bq/kg)
C K ‡º° ‡nµ„´¤¤´œ˜£µ¡‹Î µÁ¡µ³ °Š 40K Ĝ®œn ª¥ °Š (Bq/kg)
œ°„‹µ„œ¸Ê ¥´Šµ¤µ¦™œÎµ‡nµ D š¸É ŗoĜ¤„µ¦š¸É (1) Ĝ„µ¦‡Îµœª–®µ‡nµž¦·¤µ–¦´Š¸¥´ŠŸ¨š¸Éŗo ¦´‹µ„
£µ¥œ°„¦nµŠ„µ¥ž¦³‹Îµže (annual external effective dose rate) Ĝ¡ºÊœš¸Éš¸ÉÁ„ȝ˜´ª°¥nµŠ —´ Š¤„µ¦˜n°Åžœ¸Ê (Mohanty et
al ., 2004)
Annual external effective dose rate (mSv/y ) = D(nGy/h) x 8760 h x 0.2 x 0.7 (Sv/Gy) x 10-6……………(2)
×¥š¸É
‡nµ„´¤¤´œ˜£µ¡¦´Š¸ ¤¤¼¨ °ŠÁ¦Á—¸¥¤ (radium equivalent activity: Ra eq) Áž} œ‡nµ—´œ¸Â—Š‡ªµ¤Áž}œ
°´œ˜¦µ¥šµŠ¦´ Š¸(radiation hazard index)œ·—®œ¹ÉŠš¸Éŗo™¼„„Î µ®œ— ¹Êœ¤µÁ¡ºÉ°ÄoÁž}œ˜´ªÂšœ °Š‡nµ„´¤¤´œ˜£µ¡
‹ÎµÁ¡µ³ °Š 226 Ra, 232Th ¨³ 40K Ž¹ÉŠµ¤µ¦™‡Îµœª–Ä®oÁž}œ‡nµÁ¡¸¥Š‡nµÁ—¸¥ª —´ŠÂ—ŠÄœ¤„µ¦—´Š˜n°Åžœ¸Ê (Beretka
and Mathew, 1985)
Raeq = CRa + 1.43CTh + 0.077CK……………..…………………………(3)