This report presents an improved method for calibrating the sodium iodide nai detectors in the mobile in situ gamma spectroscopy systems used for scanning soils for radionuclides at the femald environmental management project femp. Philips, frazier bronson, ram venkataraman, brian m. A typical diagram of a nai detector is shown below. How are the gamma rays produced, that are used in this experiment. The model 802 scintillation detector is a hermetically sealed assembly which includes a high resolution nai tl crystal, a photomultiplier tube, an internal magneticlight shield, an aluminum housing, and a 14pin connector. A labr detector is generally preferable to a nai detector. The compton effect compton scattering and gamma ray. The written name of this type of detector is usually shortened to naitl. The sodium iodide nai scintillator detector provides high efficiency. Pdf isocs characterization of sodium iodide detectors for. Ph 3324 the scintillation detector and gamma ray spectroscopy. Radseeker utilizes a detector system consisting of a sensitive inorganic scintillator, either sodium iodide nai or lanthanum bromide labr3, to convert gamma radiation to visible light. Experiment 3 gamma ray spectroscopy using naitl equipment required purpose the purpose of this experiment is to acquaint the student with some of the basic techniques used for measuring gamma rays. Semiconductor detectors the choice of a particular detector type for an application depends upon the xray or gamma energy range of interest and the.
Dunlap, experimetal physics, oxford university press. In this experiment you will use both scintillation and semiconductor detectors to study. Sodium iodide spectroscopy radiation detectors north. Become familiar with some of the basic techniques used for measuring gamma rays with a sodium iodide nai detector. Become familiar with some of the basic techniques used for measuring gamma rays with a sodium iodide nai detector that is thallium tl activated.
A 2x2 inch sodium iodide nai detector will allow the user to identify the presence of cs7 at gamma spectroscopy measurements of uranium hexafluoride in aluminmum pipe with a sodium iodide detector showing 14 of 89 pages in this report. Sep 10, 2015 something else that we can use nai detectors for is identifying specific radionuclides by measuring the energy of each individual gamma that enters the crystal this process is called gamma spectroscopy, or can also be called multichannel analysis and the instrument set up for this purpose is called a gamma spectroscopy device, or a multi. This pair carries the gammaray energy minus 2 m oc2. It consists of a single crystal of thallium activated sodium iodide optically coupled to the photocathode of a photomultiplier tube. A hpge detector considered for this study was in continuous operation for the past 15 years in. The principle component in the scintillation detector is a tl doped sodium iodide crystal nai. Anglebw advanced gamma spectroscopy efficiency calibration software angleuw update from angleb32 version 2 or 3 to anglebw version 4 anglegw additional hard copy documentation for angle references references 1 and 2 are highly recommended to the interested reader. The most important interaction mechanisms are the photoelectric effect, the compton effect, and pair production.
Snectra of cs7 and co60 using nal detector ljci iviay i. The detector used in this experiment was thallium doped sodium iodide detector as shown in figure 1. Gamma ray interactions with matter 29 a much lower fraction of incident gamma radiation than does a similar thickness of aluminum or steel. When a gamma ray energy from 10 kev to 5 mev enters a single crystal of sodium iodide activated with a thallium impurity about 0. Gammarays spectroscopy by using a thallium activated sodium. Gamma ray spectroscopy using naitl detector zafaran abdul fattah associate professor, deptt. This pair carries the gamma ray energy minus 2 m oc2. Sodium iodide nai lanthanum bromide labr 21 lanthanum bromide labr high purity germanium hpge of these, the hpge is easily the best. Gamma ray spectroscopy and the scintillation detector data to verify the compton scattering theory is collected in this experiment using a gamma ray spectrometer that consists of a scintillation detector, high voltage supply, amplifier system, and a multichannel analyzer to measure the energy distribution of the detected gamma rays. This technique has many applications, particularly in situations where rapid nondestructive analysis is required. Benchmark gamma spectroscopy measurements of uranium. Efficiency and resolution of hpge and naitl detectors.
You will calibrate the detection system using radioactive sources available at the resource centre with gamma rays of known energy and then you will measure the energy of a gamma ray from an unknown source. What is the probability that a 600 kev gamma ray undergoes photoelectric absorption in 1 cm of nai. Snectra of cs7 and co60 using nal detector ljci spectra. Pdf analysis of the relation between energy of gamma. Applied gammaray spectrometry covers real life application of the gammaray and the devices used in their experimental studies. The most common detectors include sodium iodide nai scintillation counter and high purity germanium detectors. Gamma ray spectroscopy 1 gamma ray spectroscopy theory. Something else that we can use nai detectors for is identifying specific radionuclides by measuring the energy of each individual gamma that enters the crystal this process is called gamma spectroscopy, or can also be called multichannel analysis and the instrument set up for this purpose is called a gamma spectroscopy device, or a multi. The most common detectors include sodium iodide nai scintillation counters and highpurity germanium detectors. By comparing the measured energy to the known energy of gamma rays produced by radioisotopes, the identity of the emitter can be determined. Sigmaaldrich offers a number of sodium iodide products. Relative probability of each of the three types of interactions as a function of energy. The attenuation coefficient in equation 21 is called the linear attenuation coefficient. To express the resolution in relative terms, the fwhm in ev or mev is divided by the energy of the gamma ray and usually shown as percentage.
Geometry correction in efficiency of a sodium iodide. Isocs characterization of sodium iodide detectors for gamma ray spectrometry conference paper pdf available november 2004 with 82 reads how we measure reads. Principles of gammaray spectroscopy and applications. The energy dependence of efficiency and resolution of hpge and naitl detectors using gamma ray spectroscopy were investigated in this paper. N energy resolution and efficiency where, the average value of full width at half maximum, fwhm, corresponds to the resolution of the high purity germanium hpge and sodium iodide nai tl detector. Read the section on pages 9293 of the attached reading about photons. Efficiency of hpge detector and nai tl detector as function of energy. When a gamma ray from a radioactive sample enters the crystal, some combination of three physical processes can occur.
Components of a gamma spectroscopy system detector types the most common not the only detectors in gamma spectroscopy systems. Jan 10, 2020 in gamma ray spectroscopy, the energy of incident gamma rays is measured by a detector. Gamma spectroscopy using naitl detector spectroscopy of any kind, deals with analysis of spectrum, i. Jan 01, 2010 benchmark gamma spectroscopy measurements of uranium hexafluoride in aluminmum pipe with a sodium iodide detector showing 14 of 89 pages in this report. Gamma ray spectroscopy with a sodium iodide scintillation detector was chosen as the technique, by the easiness of use, high sensitivity and possibility of identification of an inadvertent.
Gamma ray spectroscopy with nai ti and geli detectors. Why high purity germanium hpge radiation detection. For onsite applications highresolution gamma spectrometry is mostly used only to quickly identify the material and obtain a rough idea about the isotopic composition of the material, i. This light is then amplified and measured to produce an energy spectrum for radionuclide identification analysis. Naitl crystals are widely used for radiation detection. The structure of the naitl detector is illustrated in figure 3. High purity germanium and sodium iodide detector types.
The gammaray spectrum will be obtained by using a sodium iodide nai scintillator detector. This creates excited states in the crystal that decay by. Gamma ray interactions with matter university of washington. Although field portable high purity germanium detectors are available, sodium iodide detectors are still often used for field applications. Efficiency and resolution of hpge and naitl detectors using. Gamma ray spectroscopy using a naitl detector objectives. When these emissions are detected and analyzed with a spectroscopy system, a gammaray energy. Pdf isocs characterization of sodium iodide detectors. Pair production gammaray energy binding a fraction of the gammaray energy is transferred to the compton electron if gammaray energy is 2 m oc2 electron rest mass 511 kev, a positronelectron can be formed in the strong coulomb field of a nucleus. The equipment used in gamma spectroscopy includes an energy sensitive radiation detector, a pulse sorter multichannel analyzer, and associated amplifiers and data readout devices.
Gammaray interactions with matter 29 a much lower fraction of incident gamma radiation than does a similar thickness of aluminum or steel. This experiment involves the use of radioactive sources and high voltages applied to the nai scintillation detector. This book is organized into 9 chapters, and starts with discussions of the various decay processes, the possible interaction mechanisms of gamma radiation with matter, and the intrinsic and extrinsic variables, which affect the. The scintillation detector and gamma ray spectroscopy required background reading attached are several pages from an appendix on the web for tiplerllewellyn modern physics. Naiti detector is the most widely detector use to detect gamma rays. Calibration of nai in situ gamma spectroscopy systems. These resolution values are expressed in absolute terms. Isocs characterization of sodium iodide detectors for gammaray spectrometry sasha a. N108 isocs characterization of sodium iodide detectors. When a gamma ray enters the detector, it interacts by causing ionization of the sodium iodide. Benchmark gamma spectroscopy measurements of uranium hexafluoride in aluminmum pipe with a sodium iodide detector showing 14 of 89 pages in this report. Naiti detector is the m ost widely detector use to detect gam ma rays. Gamma and xray detection introduction canberra industries. Gamma spectroscopy detectors are passive materials that wait for a gamma interaction to occur in the detector volume.
An introduction objective the primary objective of this experiment is to use an naitl detector, photomultiplier tube and multichannel analyzer software system to obtain the major primary gamma peaks of various elements, and to compare the acquired values with theoretical predictions. The naid unit is a nai detector specially designed for use in the measurement of uranium enrichment, and is used by the. Ti scintillation counter california state university stanislaus, department offisics, turlock, ca 95380 5182014 in this paper we discuss the innerworkingsofthe thalliumactivatednat detector and its ability to resolve spectra. A hpge detector considered for this study was in continuous operation for the past 15 years in our laboratory. Fast response with high sensitivity tells the operator that this is the right time and place to make a measurement. The improved method is faster, safer, and better at.
Gammaray spectroscopy is the quantitative study of the energy spectra of gammaray sources, such as in the nuclear industry, geochemical investigation, and astrophysics most radioactive sources produce gamma rays, which are of various energies and intensities. A 2x2 inch sodium iodide nai detector will allow the user to identify the presence of cs7 at gamma ray spectroscopy fig. Experiment 3 gammaray spectroscopy using naitl equipment required purpose the purpose of this experiment is to acquaint the student with some of the basic techniques used for measuring gamma rays. This will briefly refresh your memory about the three ways that photons can lose. It was found that the resolution of the detector was directly proportional to the energy of gamma ray and its efficiency was exponentially proportional to the gamma ray energy. Pdf gammarays spectroscopy by using a thallium activated. The atoms of these type of detectors are easily excited by radiation and produce a spectrum that is characteristic of the chemical element present. Uzair latif, imran younus department of physics lahore. It is based on the use of a thalliumactivated sodium iodide detector. The gamma ray spectrum will be obtained by using a sodium iodide nai scintillator detector.
Pair production gamma ray energy binding a fraction of the gamma ray energy is transferred to the compton electron if gamma ray energy is 2 m oc2 electron rest mass 511 kev, a positronelectron can be formed in the strong coulomb field of a nucleus. Sodium iodide spectroscopy radiation detectors of all the available scintillators naitl is the most extensively used material. From the graph near the end of the guide, calculate the mean free path of a 1 mev gamma ray in sodium iodide specific gravity 3. Advanced gamma spectroscopy efficiency calibration software. By what means does the sodium iodide detector detect photons. For example, a sodium iodide nai detector may have a fwhm of 9. A geometry correction file can also be generated for use in ortecs gammavision application so that the. Hpge detectors have a 2030x improvement in resolution as compared to that of sodium iodide nai detectors.
Gammaray spectroscopy using a naitl detector objectives. Gamma ray spectroscopy with naitl and hpge detectors. Of physics, faculty of education zingbar aden university doi. Nai tl sodium iodide scintillation detectors berkeley. Additionally, we analyze a sample spectrum of60co and 3tcs.
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