Application of MCP-N (Lif: Mg, Cu, P) TL detectors in monitoring environmental radiation

Abstract

Thermoluminescent MCP-N detectors based on LiF:Mg,Cu,P are by about 2 orders of magnitude more sensitive than TLD-100 detectors based on conventional LiF:Mg,Ti, which makes it possible to use them in short-term monitoring of ionizing radiation in the environment (e. g., over a two-week period, rather than over 3-12 months). We describe the properties of MCP-N detectors and methods of their application in environmental monitoring. The system was tested in short and long-term exposure periods at 100 sites around Krakow region. MCP-N detectors were then applied to measure variation of radiation dose rate at four selected villages in Serbia, where depleted uranium ammunition was deployed in 1999. Together with short-term thermoluminescent dosimetry, in situ measurements using proportional counters were per formed in order to assess the range of variation of natural radiation background in these villages. The mean terrestrial kerma dose rate in these villages was found to vary between 85 and 116 nGyh?1 and the average ambient dose equivalent rate H*(10) determined by thermoluminescent detectors and by proportional counter measurements was 160 nSvh?1. These values of natural radiation back ground dose rates can be applied as reference levels for field measurements around other sites where depleted uranium ammunition was deployed.Termoluminiscentni MCP-N detektori na bazi LiF:Mg,Cu,P su za dva reda velicine osetljiviji od konvencionalnih detektora na bazi LiF:Mg,Ti, zbog cega se upotrebljavaju u kratkotrajnom i orijentacionom monitoringu jonizujucih zracenja iz prirode (sto prakticno obuhvata pe riod od preko dve nedelje umesto 3-12 meseci). U radu se opisuju svojstva MCP-N detektora i metode za njihovu primenu u monitoringu jonizujucih zracenja iz prirode. Sistem je prevashodno testiran u kratkotrajnim i dugotrajnim izlaganjima jonizujucim zracenjima iz prirode na preko 100 mernih mesta u podrucju oko Krakova. MCP-N detektori su zatim upotrebljeni za referentna merenja brzine doze u okolini cetiri ruralne zajednice u Srbiji, namenski odabrane, u kojima je 1999. godine rasprsena municija sa osiromasenim uranijumom. Istovremeno je prilikom postavljanja ovih MCP-N detektora u ruralnim zajednicama, in situ paralelno izvrseno merenje brzine doze sa proporcionalnim brojacem, sa ciljem procene opsega varijacije osnovnog nivoa zracenja iz prirode u ispitivanim ruralnim zajednicama. Srednja vrednost terestrijalne brzine doze kerme u ispitivanim ruralnim zajednicama varirala je u opsegu od 85 do 116 nGyh?1 a srednja vrednost ambijentalne ekvivalentne brzine doze H*(10) odredjene pomocu termoluminiscentnih detektora i proporcionalnim brojacem iznosila je 160 nSvh?1. Ove izmerene vrednosti osnovnih nivoa zracenja iz prirode mogu se koristiti kao referentni nivoi terenskih merenja u okolini svih drugih podrucja pogodjenih municijom sa osiromasenim uranijumom.