Diş Minesinin Elektron Spin Rezonans (ESR) Tarihlendirme ve Dozimetri Çalışmalarında En Uygun Modülasyon Genliğinin Belirlenmesi

Geçmiş yaşam ve ekoloji hakkında önemli bilgiler veren fosil kalıntıları, özellikle doğa tarihi ve canlı evriminde önemli bir yeresahiptir. Son zamanlarda, bu alanda elde edilen verileri değerlendirmek için disiplinler arası tarihlendirme çalışmaları yapılmakta vebirçok farklı teknik kullanılmaktadır. Elektron Spin Rezonans (ESR) (veya diğer adıyla Elektron Paramanyetik Rezonans, (EPR)) mutlak tarihleme ve dozimetriçalışmalarında kullanılan yöntemlerden biridir. Işınlanmış materyaller tarafından soğrulan radyasyon dozu sonucu elde edilenradyasyon merkezli radikallerin belirlenmesi ile ilgilenir. ESR yöntemi ile yapılan dozimetri ve tarihlendirme çalışmalarında önemlisorunlardan birisi, deneysel parametrelerin biriken doz üzerinde bağımlılığının olmasıdır. Materyallerin gerçek yaşlarınınbelirlenmesinde etkili olan doz değeri ESR merkezlerinin kararlığından, numune hazırlama ya da ölçüm işlemleri gibi çeşitliaşamalardan etkilenmektedir. Bu çalışmada, diş minesi ile yapılan ESR tarihlendirme ve dozimetri çalışmalarında modülasyon genliği parametresinin ESR sinyalşiddetini nasıl etkilediği incelendi. Deneysel çalışma için, Köşkhöyük arkeoloji kazı alanından çıkarılan arkeolojik hayvan diş minesiörneği kullanıldı. Ölçüm işleminden önce diş minesi örneği, laboratuvar ortamında diş üzerine mekanik ve kimyasal işlemleruygulanarak hazırlandı. Daha sonra örnek, 60Co gama-kaynağı ile yaklaşık 1kGy ışınlandı. Işınlama işleminden sonra örneğin ESRspektrumları X-Band ESR Spektrometresi yardımıyla oda sıcaklığında farklı modülasyon genliği değerlerinde kaydedildi. Elde edilensonuçlara göre, çalışmada incelenen diş minesi örneğinin ESR ölçümleri için en uygun modülasyon genliği değeri belirlendi.

Determination of Optimal Modulation Amplitude for Electron SpinResonance (ESR) Dating and Dosimetry Studies of Tooth Enamel

Fossil remains, which provide important information about past life and ecology, are especially important in natural history and lifeevolution. Recently, many interdisciplinary dating studies have been conducted and many different techniques have been used toinvestigate the data obtained in this field. Electron Spin Resonance (ESR) (or alternatively, Electron Paramagnetic Resonance, EPR)is one of the methods used in absolute dating and dosimetry studies. It is based on determination of the radiation-centered radicalsobtained from the radiation dose absorbed by irradiated materials. One of the important problems in dosimetry and dating studies performed with ESR method is the dependence of experimentalparameters on the accumulated dose. The accumulated dose value is effective in determining the actual result of the dating anddosimetric samples. This value is influenced from the stability of the ESR centers, experimental stages, sample preparation ormeasurement processes. In this study, how the modulation amplitude parameter affects ESR signal intensity in ESR dating and dosimetry studies of toothenamel investigated. The selective archaeological animal tooth enamel sample was used from the archaeological site of Köşk Höyük,in Turkey for experimental studies. This sample was prepared with combined processes of mechanical and chemical treatment of toothin laboratory. Tooth enamel sample was irradiated by 60Co gamma-ray source in dose of 1kGy. After irradiation, ESR spectra wererecorded at different modulation amplitude values at room temperature using X-band ESR Spectrometer. According to the resultsobtained, the most suitable modulation amplitude values for ESR measurements of tooth enamel sample examined in the study.

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