effect of magnet rod position to crystal on response function of scintillation detector NAI[T1]

ABSTRACT

The effect of the magnet rod position of [0.5mT] intensity to the Scintillation detector Nal[T1] of 3" x 3" size [consist of the crystal and the photomultiplier tube] [P.M.] has been studied in this work. Six positions have been used which they are at the crystal face [P1], at the middle of the crystal [P2], at the end of the crystal - the photocathode [P3], at the begin of the [P.M. [P4], at the middle of [P.M.] [P5] and of its end [P6]. The Co-60 radioactive Source was used in this study via the response function of Nal[T1] detector at each position, and to do the comparison, the energy spectrum was taken without the magnet rod [W.O.]. The result shows that the total area of the spectrum decrease when the magnet rod is exist with a percentage ratio 93.1 percent at P2 position and the scattering area decrease also with 88.2 percent ratio at [P2] position too. The net area of the photopeaks [1.173 and 1.333] MeV was decrease with the existane of the magnet rod with 87.9 percent for the first peak at [P3] position and with 84.5 percent and 85.5 percent for the second peak at the position [P2] and [P4] respectively. The energy resolutions will be worse [increase in magnitude] with the existence of the magnet rod especially at [P3] and [P5] positions