4 research outputs found
New method for determination of temperature in spallation reactions
We propose a new method for determination of temperature in spallation events. It is shown that temperature can be determined by applying the friction model of energy dissipation in participant-spectator model of a spallation process. First order estimate of temperature dependence of the participant zone on reaction Q-value is obtained from the Fermi gas model considerations. The heat diffusion process is also discussed
Methods for calculating coincidence summing effects for gamma spectroscopy
Π£ ΠΎΠ²ΠΎΡ Π΄ΠΎΠΊΡΠΎΡΡΠΊΠΎΡ Π΄ΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠΈ ΡΠ°Π·ΠΌΠ°ΡΡΠ°Π½ΠΎ ΡΠ΅ ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎ ΡΡΠΌΠΈΡΠ°ΡΠ΅ ΠΊΠΎΡΠ΅ ΡΠ΅ ΡΠ°Π²ΡΠ° Ρ Π³Π°ΠΌΠ° ΡΠΏΠ΅ΠΊΡΡΠΎΠΌΠ΅ΡΡΠΈΡΠΈ. Π Π°Π·Π²ΠΈΡΠ΅Π½ ΡΠ΅ Π½ΠΎΠ² ΠΌΠ΅ΡΠΎΠ΄ Π·Π° ΠΎΠ΄ΡΠ΅ΡΠΈΠ²Π°ΡΠ΅ Π±ΡΠ·ΠΈΠ½Π° Π±ΡΠΎΡΠ°ΡΠ° Ρ Π³Π°ΠΌΠ° ΡΠΏΠ΅ΠΊΡΡΠΈΠΌΠ° ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄Π° ΠΊΠΎΠ΄ ΠΊΠΎΡΠΈΡ
ΡΠ΅ ΠΊΠ°ΡΠΊΠ°Π΄Π½Π° Π΄Π΅Π΅ΠΊΡΡΠΈΡΠ°ΡΠΈΡΠ° ΡΠ΅Π·Π³ΡΠ° ΠΎΠ΄Π²ΠΈΡΠ° ΠΈΡΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½ΠΎ ΡΠ° ΠΊΠ°ΡΠΊΠ°Π΄Π½ΠΎΠΌ Π΄Π΅Π΅ΠΊΡΡΠΈΡΠ°ΡΠΈΡΠΎΠΌ Π°ΡΠΎΠΌΡΠΊΠΎΠ³ ΠΎΠΌΠΎΡΠ°ΡΠ°. ΠΠ΅ΡΠΎΠ΄ ΡΠ΅ ΡΡΠΏΠ΅ΡΠ½ΠΎ ΠΏΡΠΈΠΌΠ΅ΡΠ΅Π½ Π½Π° ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄Π΅ ΡΠ΅ΡΠΈΡΡΠΌΠ° 139Ce, ΠΊΠΎΠ±Π°Π»ΡΠ° 57Co, Π±Π°ΡΠΈΡΡΠΌΠ° 133Ba ΠΈ Π΅Π²ΡΠΎΠΏΠΈΡΡΠΌΠ° 152Eu.
ΠΡΠ΅ΠΊΡΠΈ ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎΠ³ ΡΡΠΌΠΈΡΠ°ΡΠ° Π½Π°ΡΡΠ°ΡΡ ΠΊΠ°Π΄Π° ΡΠ΅ ΡΠ°ΡΠΏΠ°Π΄ΠΎΠΌ Π½Π΅ΠΊΠΎΠ³ ΡΠ΅Π·Π³ΡΠ° Ρ ΠΊΠ°ΡΠΊΠ°Π΄Π½ΠΈΠΌ ΠΏΡΠ΅Π»Π°Π·ΠΈΠΌΠ° Π΅ΠΌΠΈΡΡΡΡ Π΄Π²Π° ΠΈΠ»ΠΈ Π²ΠΈΡΠ΅ ΡΠΎΡΠΎΠ½Π°, Ρ ΠΊΡΠ°ΡΠΊΠΎΠΌ Π²ΡΠ΅ΠΌΠ΅Π½ΡΠΊΠΎΠΌ ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»Ρ, ΠΊΡΠ°ΡΠ΅ΠΌ ΠΎΠ΄ Π²ΡΠ΅ΠΌΠ΅Π½Π° ΡΠ°Π·Π»Π°Π³Π°ΡΠ° Π΄Π΅ΡΠ΅ΠΊΡΠΎΡΠ°, Π° ΠΊΠ°ΠΎ ΡΠ΅Π·ΡΠ»ΡΠ°Ρ, Π΄Π΅ΡΠ΅ΠΊΡΠΎΡ ΠΈΡ
ΡΡΠ΅ΡΠΈΡΠ° ΠΊΠ°ΠΎ ΡΠ΅Π΄Π½Ρ ΠΈΠ½ΡΠ΅ΡΠ°ΠΊΡΠΈΡΡ, ΡΠ°ΠΊΠΎ Π΄Π° ΡΠ΅ Π΅Π½Π΅ΡΠ³Π΅ΡΡΠΊΠΈ ΡΡΠ°Π½ΡΡΠ΅Ρ ΠΏΡΠ΅Π΄ΡΡΠ°Π²ΡΠ°ΡΠΈ ΡΡΠΌΡ ΡΡΠ°Π½ΡΡΠ΅ΡΠ° ΠΏΠΎΡΠ΅Π΄ΠΈΠ½Π°ΡΠ½ΠΈΡ
ΠΈΠ½ΡΠ΅ΡΠ°ΠΊΡΠΈΡΠ° (ΡΡΠΌΠ°ΡΠΈΠΎΠ½ΠΈ ΠΏΠΈΠΊ). Π’ΠΎ Π΄ΠΎΠ²ΠΎΠ΄ΠΈ Π΄ΠΎ ΠΏΠΎΠ²Π΅ΡΠ°ΡΠ° ΠΎΠ΄Π±ΡΠΎΡΠ° Ρ ΡΡΠΌΠ°ΡΠΈΠΎΠ½ΠΎΠΌ ΠΏΠΈΠΊΡ Π°Π»ΠΈ ΠΈ Π΄ΠΎ ΡΠΌΠ°ΡΠ΅ΡΠ° ΠΎΠ΄Π±ΡΠΎΡΠ° Ρ ΡΠΎΡΠΎΠΏΠΈΠΊΠΎΠ²ΠΈΠΌΠ° ΠΊΠ°ΡΠΊΠ°Π΄Π½ΠΈΡ
ΡΠΎΡΠΎΠ½Π°. ΠΡΠΈΠΌΠ΅Π½Π° Π°Π½Π°Π»ΠΈΡΠΈΡΠΊΠΎΠ³ ΠΏΡΠΈΡΡΡΠΏΠ° ΠΏΡΠΎΠ±Π»Π΅ΠΌΡ ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎΠ³ ΡΡΠΌΠΈΡΠ°ΡΠ° Π΄Π°ΡΠ΅ ΠΌΠΎΠ³ΡΡΠ½ΠΎΡΡ Π΄Π° ΡΠ΅ ΠΏΡΠ΅Π΄Π²ΠΈΠ΄Π΅ ΡΠ²ΠΈ ΡΡΠΌΠ°ΡΠΈΠΎΠ½ΠΈ ΠΏΠΈΠΊΠΎΠ²ΠΈ ΠΊΠΎΡΠΈ ΡΠ΅ ΠΌΠΎΠ³Ρ ΠΏΠΎΡΠ°Π²ΠΈΡΠΈ Ρ ΡΠΏΠ΅ΠΊΡΡΡ. ΠΠ²ΠΈΠΌ ΠΏΡΠΈΡΡΡΠΏΠΎΠΌ ΡΠ΅ ΠΌΠΎΠΆΠ΅ ΠΎΠ΄ΡΠ΅Π΄ΠΈΡΠΈ Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡ ΠΈΠ·Π²ΠΎΡΠ° Π΄ΠΈΡΠ΅ΠΊΡΠ½ΠΎ Π±Π΅Π· ΠΊΠ°Π»ΠΈΠ±ΡΠ°ΡΠΈΡΠ΅ Π΄Π΅ΡΠ΅ΠΊΡΠΎΡΠ°, ΡΡΠΎ ΡΠ΅ Π²Π΅ΠΎΠΌΠ° Π·Π½Π°ΡΠ°ΡΠ½ΠΎ Ρ ΠΌΠ΅ΡΡΠΎΠ»ΠΎΠ³ΠΈΡΠΈ ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄Π°. ΠΠ΄Π½ΠΎΡΠ½ΠΎ, Π½Π° ΠΎΡΠ½ΠΎΠ²Ρ Π²ΡΠ΅Π΄Π½ΠΎΡΡΠΈ ΠΏΠΎΠ²ΡΡΠΈΠ½Π° ΠΏΠΈΠΊΠΎΠ²Π° Ρ ΡΠΏΠ΅ΠΊΡΡΡ ΠΈ ΠΏΠΎΠ·Π½Π°Π²Π°ΡΠ΅ΠΌ Π²Π΅ΡΠΎΠ²Π°ΡΠ½ΠΎΡΠ° ΠΏΡΠ΅Π»Π°Π·Π° ΠΈΠ·ΠΌΠ΅ΡΡ ΠΏΠΎΠ±ΡΡΠ΅Π½ΠΈΡ
ΡΡΠ°ΡΠ° ΡΠ΅Π·Π³ΡΠ°, ΠΌΠΎΠ³ΡΡΠ΅ ΡΠ΅ ΠΎΠ΄ΡΠ΅Π΄ΠΈΡΠΈ ΠΈ Π΅ΡΠΈΠΊΠ°ΡΠ½ΠΎΡΡΠΈ Π΄Π΅ΡΠ΅ΠΊΡΠΈΡΠ΅ ΠΈ Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡ ΡΠ°Π΄ΠΈΠΎΠ°ΠΊΡΠΈΠ²Π½ΠΎΠ³ ΠΈΠ·Π²ΠΎΡΠ°.
ΠΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠ° ΡΠ΅ ΠΎΠ±ΡΡ
Π²Π°ΡΠΈΠ»Π° Π°Π½Π°Π»ΠΈΠ·Ρ ΠΈ ΠΌΠΎΠ΄ΠΈΡΠΈΠΊΠ°ΡΠΈΡΡ ΠΏΠΎΡΡΠΎΡΠ΅ΡΠΈΡ
ΠΌΠ΅ΡΠΎΠ΄Π° Π·Π° ΡΠ΅ΡΠ°Π²Π°ΡΠ΅ ΠΏΡΠΎΠ±Π»Π΅ΠΌΠ° ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎΠ³ ΡΡΠΌΠΈΡΠ°ΡΠ° ΡΠ²ΠΎΡΠ΅ΡΠ΅ΠΌ Π½ΠΎΠ²ΠΎΠ³ ΠΌΠ΅ΡΠΎΠ΄Π° ΡΠ° ΡΠ΅Π΄Π½ΠΎΡΡΠ°Π²Π½ΠΈΡΠΎΠΌ Π°Π»Π³Π΅Π±ΡΠΎΠΌ. ΠΠΎΠ² Π°Π½Π°Π»ΠΈΡΠΈΡΠΊΠΈ ΠΏΡΠΈΡΡΡΠΏ ΠΊΠΎΡΠΈ ΡΠΌΠΎ ΡΠ°Π·Π²ΠΈΠ»ΠΈ ΠΎΠΏΠΈΡΠ°Π½ ΡΠ΅ Ρ ΡΠ΅ΡΡΠΎΠΌ ΠΏΠΎΠ³Π»Π°Π²ΡΡ Π΄ΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠ΅. ΠΠ°ΠΊΠΎΠ½ ΡΠ΅Π΄Π½ΠΎΡΡΠ°Π²Π½ΠΈΡ
Π°ΡΠΈΡΠΌΠ΅ΡΠΈΡΠΊΠΈΡ
ΠΎΠΏΠ΅ΡΠ°ΡΠΈΡΠ° ΠΌΠΎΠΆΠ΅ ΡΠ΅ Π΄ΠΎΠ±ΠΈΡΠΈ ΡΠΈΡΡΠ΅ΠΌ ΡΠ΅Π΄Π½Π°ΡΠΈΠ½Π° Π±ΡΠ·ΠΈΠ½Π° Π±ΡΠΎΡΠ°ΡΠ° Π·Π° ΠΎΠ΄ΡΠ΅ΡΠΈΠ²Π°ΡΠ΅ Π΅ΡΠΈΠΊΠ°ΡΠ½ΠΎΡΡΠΈ Π΄Π΅ΡΠ΅ΠΊΡΠΈΡΠ΅ ΠΈ Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄Π°. ΠΠ½Π°ΡΠ°Ρ Π½ΠΎΠ²ΠΎΠ³ ΠΌΠ΅ΡΠΎΠ΄Π° ΡΠ΅ ΡΡΠΎ Π½Π° ΡΠ΅Π΄Π½ΠΎΡΡΠ°Π²Π°Π½ Π½Π°ΡΠΈΠ½ Π΄Π°ΡΠ΅ ΠΏΡΠΎΡΠ°ΡΡΠ½ Π΄ΠΎΠΏΡΠΈΠ½ΠΎΡΠ° Π΅ΡΠ΅ΠΊΠ°ΡΠ° ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎΠ³ ΡΡΠΌΠΈΡΠ°ΡΠ°. ΠΠΎΡΡΠΎ ΡΠ΅ ΡΠ΅Π·ΡΠ»ΡΠ°ΡΠΈ Π΄ΠΎΠ±ΠΈΡΠ°ΡΡ Π½Π° ΡΠ°ΡΠ½ΠΈΡΠΈ Π½Π°ΡΠΈΠ½, Π½ΠΎΠ² ΠΏΡΠΈΡΡΡΠΏ ΡΠ΅ ΠΌΠ½ΠΎΠ³ΠΎ Π»Π°ΠΊΡΠΈ Π·Π° ΠΏΡΠ°ΠΊΡΠΈΡΠ½Ρ ΡΠΏΠΎΡΡΠ΅Π±Ρ. ΠΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠ° ΠΎΠ±ΡΡ
Π²Π°ΡΠ° ΠΈ ΡΡΠΏΠ΅ΡΠ½Ρ ΠΏΡΠΈΠΌΠ΅Π½Ρ Π½ΠΎΠ²ΠΎΠ³ ΠΌΠ΅ΡΠΎΠ΄Π° Π½Π° ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄ΠΈΠΌΠ° ΠΊΠΎΡΠΈ ΡΠ΅ ΠΊΠΎΡΠΈΡΡΠ΅ Ρ ΡΠ΅Π°Π»Π½ΠΈΠΌ Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠΈΠΌΠ°. ΠΠ°Ρ ΡΠ΅ Π΄Π΅ΡΠ°ΡΠ°Π½ ΠΎΠΏΠΈΡ ΠΌΠ΅ΡΠΎΠ΄Π° ΠΎΠ΄ ΡΠΎΡΠΌΠΈΡΠ°ΡΠ° ΠΎΠ΄Π³ΠΎΠ²Π°ΡΠ°ΡΡΡΠΈΡ
ΠΌΠ°ΡΡΠΈΡΠ° Π΄ΠΎ ΠΊΠΎΠ½Π°ΡΠ½ΠΎΠ³ ΡΠ΅Π·ΡΠ»ΡΠ°ΡΠ°...This thesis considers the coincidence summing that occurs in gamma spectroscopy. A new method has been developed for deriving the counting rate for gamma spectra of radionuclides in which the nucleus de-excitation cascade takes place simultaneously with the cascade de-excitation of the atomic layer. This method is successfully applied to the decay of radionuclides 139Ce, 57Co, 133Ba and 152Eu.
The coincidence summing effects occur whenever two or more cascading photons are emitted from the same nucleus and detected within the resolving time of spectrometer. As a result, the spectrometer treats them as one interaction, so that the energy transfer represents the sum of the transfers of individual interactions (summation peak). This leads to an increase of counts in summation peaks as well as the reduction of counts in full-energy peaks of casscading photons. The application of analytical approaches to coincidence summing effects makes it possible to predict all summation peaks that occur in the spectrum. This approach also allows us to determine the activity of sources directly without calibration of the detector, which is very important in metrology of radionuclides. Accordingly, based on the value of the peak area in the spectrum and knowledge of probability transitions between excited states of a nucleus, it is possible to determine the efficiency of detection and activity of radioactive sources.
The dissertation includes an analysis and modification of the existing methods for solving the problems of coincidence summarizing by introducing the new method with simpler algebra. The new analytical approach that we have developed is described in the sixth chapter of the thesis. Following simple arithmetic operations, the system counting rate equation can be obtained for the determination of the detection efficiency and radionuclide activity.
The importance of the new method is that it gives, in a simple way, an estimate of contribution of coincidence summing effects. Since the results are obtained in a clearer way, the new approach is much easier for practical use. The dissertation also..
Methods for calculating coincidence summing effects for gamma spectroscopy
Π£ ΠΎΠ²ΠΎΡ Π΄ΠΎΠΊΡΠΎΡΡΠΊΠΎΡ Π΄ΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠΈ ΡΠ°Π·ΠΌΠ°ΡΡΠ°Π½ΠΎ ΡΠ΅ ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎ ΡΡΠΌΠΈΡΠ°ΡΠ΅ ΠΊΠΎΡΠ΅ ΡΠ΅ ΡΠ°Π²ΡΠ° Ρ Π³Π°ΠΌΠ° ΡΠΏΠ΅ΠΊΡΡΠΎΠΌΠ΅ΡΡΠΈΡΠΈ. Π Π°Π·Π²ΠΈΡΠ΅Π½ ΡΠ΅ Π½ΠΎΠ² ΠΌΠ΅ΡΠΎΠ΄ Π·Π° ΠΎΠ΄ΡΠ΅ΡΠΈΠ²Π°ΡΠ΅ Π±ΡΠ·ΠΈΠ½Π° Π±ΡΠΎΡΠ°ΡΠ° Ρ Π³Π°ΠΌΠ° ΡΠΏΠ΅ΠΊΡΡΠΈΠΌΠ° ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄Π° ΠΊΠΎΠ΄ ΠΊΠΎΡΠΈΡ
ΡΠ΅ ΠΊΠ°ΡΠΊΠ°Π΄Π½Π° Π΄Π΅Π΅ΠΊΡΡΠΈΡΠ°ΡΠΈΡΠ° ΡΠ΅Π·Π³ΡΠ° ΠΎΠ΄Π²ΠΈΡΠ° ΠΈΡΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½ΠΎ ΡΠ° ΠΊΠ°ΡΠΊΠ°Π΄Π½ΠΎΠΌ Π΄Π΅Π΅ΠΊΡΡΠΈΡΠ°ΡΠΈΡΠΎΠΌ Π°ΡΠΎΠΌΡΠΊΠΎΠ³ ΠΎΠΌΠΎΡΠ°ΡΠ°. ΠΠ΅ΡΠΎΠ΄ ΡΠ΅ ΡΡΠΏΠ΅ΡΠ½ΠΎ ΠΏΡΠΈΠΌΠ΅ΡΠ΅Π½ Π½Π° ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄Π΅ ΡΠ΅ΡΠΈΡΡΠΌΠ° 139Ce, ΠΊΠΎΠ±Π°Π»ΡΠ° 57Co, Π±Π°ΡΠΈΡΡΠΌΠ° 133Ba ΠΈ Π΅Π²ΡΠΎΠΏΠΈΡΡΠΌΠ° 152Eu.
ΠΡΠ΅ΠΊΡΠΈ ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎΠ³ ΡΡΠΌΠΈΡΠ°ΡΠ° Π½Π°ΡΡΠ°ΡΡ ΠΊΠ°Π΄Π° ΡΠ΅ ΡΠ°ΡΠΏΠ°Π΄ΠΎΠΌ Π½Π΅ΠΊΠΎΠ³ ΡΠ΅Π·Π³ΡΠ° Ρ ΠΊΠ°ΡΠΊΠ°Π΄Π½ΠΈΠΌ ΠΏΡΠ΅Π»Π°Π·ΠΈΠΌΠ° Π΅ΠΌΠΈΡΡΡΡ Π΄Π²Π° ΠΈΠ»ΠΈ Π²ΠΈΡΠ΅ ΡΠΎΡΠΎΠ½Π°, Ρ ΠΊΡΠ°ΡΠΊΠΎΠΌ Π²ΡΠ΅ΠΌΠ΅Π½ΡΠΊΠΎΠΌ ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»Ρ, ΠΊΡΠ°ΡΠ΅ΠΌ ΠΎΠ΄ Π²ΡΠ΅ΠΌΠ΅Π½Π° ΡΠ°Π·Π»Π°Π³Π°ΡΠ° Π΄Π΅ΡΠ΅ΠΊΡΠΎΡΠ°, Π° ΠΊΠ°ΠΎ ΡΠ΅Π·ΡΠ»ΡΠ°Ρ, Π΄Π΅ΡΠ΅ΠΊΡΠΎΡ ΠΈΡ
ΡΡΠ΅ΡΠΈΡΠ° ΠΊΠ°ΠΎ ΡΠ΅Π΄Π½Ρ ΠΈΠ½ΡΠ΅ΡΠ°ΠΊΡΠΈΡΡ, ΡΠ°ΠΊΠΎ Π΄Π° ΡΠ΅ Π΅Π½Π΅ΡΠ³Π΅ΡΡΠΊΠΈ ΡΡΠ°Π½ΡΡΠ΅Ρ ΠΏΡΠ΅Π΄ΡΡΠ°Π²ΡΠ°ΡΠΈ ΡΡΠΌΡ ΡΡΠ°Π½ΡΡΠ΅ΡΠ° ΠΏΠΎΡΠ΅Π΄ΠΈΠ½Π°ΡΠ½ΠΈΡ
ΠΈΠ½ΡΠ΅ΡΠ°ΠΊΡΠΈΡΠ° (ΡΡΠΌΠ°ΡΠΈΠΎΠ½ΠΈ ΠΏΠΈΠΊ). Π’ΠΎ Π΄ΠΎΠ²ΠΎΠ΄ΠΈ Π΄ΠΎ ΠΏΠΎΠ²Π΅ΡΠ°ΡΠ° ΠΎΠ΄Π±ΡΠΎΡΠ° Ρ ΡΡΠΌΠ°ΡΠΈΠΎΠ½ΠΎΠΌ ΠΏΠΈΠΊΡ Π°Π»ΠΈ ΠΈ Π΄ΠΎ ΡΠΌΠ°ΡΠ΅ΡΠ° ΠΎΠ΄Π±ΡΠΎΡΠ° Ρ ΡΠΎΡΠΎΠΏΠΈΠΊΠΎΠ²ΠΈΠΌΠ° ΠΊΠ°ΡΠΊΠ°Π΄Π½ΠΈΡ
ΡΠΎΡΠΎΠ½Π°. ΠΡΠΈΠΌΠ΅Π½Π° Π°Π½Π°Π»ΠΈΡΠΈΡΠΊΠΎΠ³ ΠΏΡΠΈΡΡΡΠΏΠ° ΠΏΡΠΎΠ±Π»Π΅ΠΌΡ ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎΠ³ ΡΡΠΌΠΈΡΠ°ΡΠ° Π΄Π°ΡΠ΅ ΠΌΠΎΠ³ΡΡΠ½ΠΎΡΡ Π΄Π° ΡΠ΅ ΠΏΡΠ΅Π΄Π²ΠΈΠ΄Π΅ ΡΠ²ΠΈ ΡΡΠΌΠ°ΡΠΈΠΎΠ½ΠΈ ΠΏΠΈΠΊΠΎΠ²ΠΈ ΠΊΠΎΡΠΈ ΡΠ΅ ΠΌΠΎΠ³Ρ ΠΏΠΎΡΠ°Π²ΠΈΡΠΈ Ρ ΡΠΏΠ΅ΠΊΡΡΡ. ΠΠ²ΠΈΠΌ ΠΏΡΠΈΡΡΡΠΏΠΎΠΌ ΡΠ΅ ΠΌΠΎΠΆΠ΅ ΠΎΠ΄ΡΠ΅Π΄ΠΈΡΠΈ Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡ ΠΈΠ·Π²ΠΎΡΠ° Π΄ΠΈΡΠ΅ΠΊΡΠ½ΠΎ Π±Π΅Π· ΠΊΠ°Π»ΠΈΠ±ΡΠ°ΡΠΈΡΠ΅ Π΄Π΅ΡΠ΅ΠΊΡΠΎΡΠ°, ΡΡΠΎ ΡΠ΅ Π²Π΅ΠΎΠΌΠ° Π·Π½Π°ΡΠ°ΡΠ½ΠΎ Ρ ΠΌΠ΅ΡΡΠΎΠ»ΠΎΠ³ΠΈΡΠΈ ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄Π°. ΠΠ΄Π½ΠΎΡΠ½ΠΎ, Π½Π° ΠΎΡΠ½ΠΎΠ²Ρ Π²ΡΠ΅Π΄Π½ΠΎΡΡΠΈ ΠΏΠΎΠ²ΡΡΠΈΠ½Π° ΠΏΠΈΠΊΠΎΠ²Π° Ρ ΡΠΏΠ΅ΠΊΡΡΡ ΠΈ ΠΏΠΎΠ·Π½Π°Π²Π°ΡΠ΅ΠΌ Π²Π΅ΡΠΎΠ²Π°ΡΠ½ΠΎΡΠ° ΠΏΡΠ΅Π»Π°Π·Π° ΠΈΠ·ΠΌΠ΅ΡΡ ΠΏΠΎΠ±ΡΡΠ΅Π½ΠΈΡ
ΡΡΠ°ΡΠ° ΡΠ΅Π·Π³ΡΠ°, ΠΌΠΎΠ³ΡΡΠ΅ ΡΠ΅ ΠΎΠ΄ΡΠ΅Π΄ΠΈΡΠΈ ΠΈ Π΅ΡΠΈΠΊΠ°ΡΠ½ΠΎΡΡΠΈ Π΄Π΅ΡΠ΅ΠΊΡΠΈΡΠ΅ ΠΈ Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡ ΡΠ°Π΄ΠΈΠΎΠ°ΠΊΡΠΈΠ²Π½ΠΎΠ³ ΠΈΠ·Π²ΠΎΡΠ°.
ΠΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠ° ΡΠ΅ ΠΎΠ±ΡΡ
Π²Π°ΡΠΈΠ»Π° Π°Π½Π°Π»ΠΈΠ·Ρ ΠΈ ΠΌΠΎΠ΄ΠΈΡΠΈΠΊΠ°ΡΠΈΡΡ ΠΏΠΎΡΡΠΎΡΠ΅ΡΠΈΡ
ΠΌΠ΅ΡΠΎΠ΄Π° Π·Π° ΡΠ΅ΡΠ°Π²Π°ΡΠ΅ ΠΏΡΠΎΠ±Π»Π΅ΠΌΠ° ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎΠ³ ΡΡΠΌΠΈΡΠ°ΡΠ° ΡΠ²ΠΎΡΠ΅ΡΠ΅ΠΌ Π½ΠΎΠ²ΠΎΠ³ ΠΌΠ΅ΡΠΎΠ΄Π° ΡΠ° ΡΠ΅Π΄Π½ΠΎΡΡΠ°Π²Π½ΠΈΡΠΎΠΌ Π°Π»Π³Π΅Π±ΡΠΎΠΌ. ΠΠΎΠ² Π°Π½Π°Π»ΠΈΡΠΈΡΠΊΠΈ ΠΏΡΠΈΡΡΡΠΏ ΠΊΠΎΡΠΈ ΡΠΌΠΎ ΡΠ°Π·Π²ΠΈΠ»ΠΈ ΠΎΠΏΠΈΡΠ°Π½ ΡΠ΅ Ρ ΡΠ΅ΡΡΠΎΠΌ ΠΏΠΎΠ³Π»Π°Π²ΡΡ Π΄ΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠ΅. ΠΠ°ΠΊΠΎΠ½ ΡΠ΅Π΄Π½ΠΎΡΡΠ°Π²Π½ΠΈΡ
Π°ΡΠΈΡΠΌΠ΅ΡΠΈΡΠΊΠΈΡ
ΠΎΠΏΠ΅ΡΠ°ΡΠΈΡΠ° ΠΌΠΎΠΆΠ΅ ΡΠ΅ Π΄ΠΎΠ±ΠΈΡΠΈ ΡΠΈΡΡΠ΅ΠΌ ΡΠ΅Π΄Π½Π°ΡΠΈΠ½Π° Π±ΡΠ·ΠΈΠ½Π° Π±ΡΠΎΡΠ°ΡΠ° Π·Π° ΠΎΠ΄ΡΠ΅ΡΠΈΠ²Π°ΡΠ΅ Π΅ΡΠΈΠΊΠ°ΡΠ½ΠΎΡΡΠΈ Π΄Π΅ΡΠ΅ΠΊΡΠΈΡΠ΅ ΠΈ Π°ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄Π°. ΠΠ½Π°ΡΠ°Ρ Π½ΠΎΠ²ΠΎΠ³ ΠΌΠ΅ΡΠΎΠ΄Π° ΡΠ΅ ΡΡΠΎ Π½Π° ΡΠ΅Π΄Π½ΠΎΡΡΠ°Π²Π°Π½ Π½Π°ΡΠΈΠ½ Π΄Π°ΡΠ΅ ΠΏΡΠΎΡΠ°ΡΡΠ½ Π΄ΠΎΠΏΡΠΈΠ½ΠΎΡΠ° Π΅ΡΠ΅ΠΊΠ°ΡΠ° ΠΊΠΎΠΈΠ½ΡΠΈΠ΄Π΅Π½ΡΠ½ΠΎΠ³ ΡΡΠΌΠΈΡΠ°ΡΠ°. ΠΠΎΡΡΠΎ ΡΠ΅ ΡΠ΅Π·ΡΠ»ΡΠ°ΡΠΈ Π΄ΠΎΠ±ΠΈΡΠ°ΡΡ Π½Π° ΡΠ°ΡΠ½ΠΈΡΠΈ Π½Π°ΡΠΈΠ½, Π½ΠΎΠ² ΠΏΡΠΈΡΡΡΠΏ ΡΠ΅ ΠΌΠ½ΠΎΠ³ΠΎ Π»Π°ΠΊΡΠΈ Π·Π° ΠΏΡΠ°ΠΊΡΠΈΡΠ½Ρ ΡΠΏΠΎΡΡΠ΅Π±Ρ. ΠΠΈΡΠ΅ΡΡΠ°ΡΠΈΡΠ° ΠΎΠ±ΡΡ
Π²Π°ΡΠ° ΠΈ ΡΡΠΏΠ΅ΡΠ½Ρ ΠΏΡΠΈΠΌΠ΅Π½Ρ Π½ΠΎΠ²ΠΎΠ³ ΠΌΠ΅ΡΠΎΠ΄Π° Π½Π° ΡΠ°Π΄ΠΈΠΎΠ½ΡΠΊΠ»ΠΈΠ΄ΠΈΠΌΠ° ΠΊΠΎΡΠΈ ΡΠ΅ ΠΊΠΎΡΠΈΡΡΠ΅ Ρ ΡΠ΅Π°Π»Π½ΠΈΠΌ Π΅ΠΊΡΠΏΠ΅ΡΠΈΠΌΠ΅Π½ΡΠΈΠΌΠ°. ΠΠ°Ρ ΡΠ΅ Π΄Π΅ΡΠ°ΡΠ°Π½ ΠΎΠΏΠΈΡ ΠΌΠ΅ΡΠΎΠ΄Π° ΠΎΠ΄ ΡΠΎΡΠΌΠΈΡΠ°ΡΠ° ΠΎΠ΄Π³ΠΎΠ²Π°ΡΠ°ΡΡΡΠΈΡ
ΠΌΠ°ΡΡΠΈΡΠ° Π΄ΠΎ ΠΊΠΎΠ½Π°ΡΠ½ΠΎΠ³ ΡΠ΅Π·ΡΠ»ΡΠ°ΡΠ°...This thesis considers the coincidence summing that occurs in gamma spectroscopy. A new method has been developed for deriving the counting rate for gamma spectra of radionuclides in which the nucleus de-excitation cascade takes place simultaneously with the cascade de-excitation of the atomic layer. This method is successfully applied to the decay of radionuclides 139Ce, 57Co, 133Ba and 152Eu.
The coincidence summing effects occur whenever two or more cascading photons are emitted from the same nucleus and detected within the resolving time of spectrometer. As a result, the spectrometer treats them as one interaction, so that the energy transfer represents the sum of the transfers of individual interactions (summation peak). This leads to an increase of counts in summation peaks as well as the reduction of counts in full-energy peaks of casscading photons. The application of analytical approaches to coincidence summing effects makes it possible to predict all summation peaks that occur in the spectrum. This approach also allows us to determine the activity of sources directly without calibration of the detector, which is very important in metrology of radionuclides. Accordingly, based on the value of the peak area in the spectrum and knowledge of probability transitions between excited states of a nucleus, it is possible to determine the efficiency of detection and activity of radioactive sources.
The dissertation includes an analysis and modification of the existing methods for solving the problems of coincidence summarizing by introducing the new method with simpler algebra. The new analytical approach that we have developed is described in the sixth chapter of the thesis. Following simple arithmetic operations, the system counting rate equation can be obtained for the determination of the detection efficiency and radionuclide activity.
The importance of the new method is that it gives, in a simple way, an estimate of contribution of coincidence summing effects. Since the results are obtained in a clearer way, the new approach is much easier for practical use. The dissertation also..
A possible improvement of the determination of Ba-133 activity and detection efficiency by the sum-peak method, by inclusion of the previously neglected transitions
In the treatment of Ba-133 decay by the method of coincidence summing, the transitions to the first two excited states of Cs-133 were ignored in former works. By applying the most accurate values for these transitions available in literature, we include them into the count rate equations and obtain solutions for the corresponding system. As a result of this more accurate forming of count rate equations, some terms, which contain previously ignored transition probabilities, turn out to be more significant than the conventionally included terms. We show that their inclusion in the system of count rate equations leads to fine improvements in the determinations of detection efficiencies and the activity of the Ba-133 source. (c) 2012 Elsevier B.V. All rights reserved