PENENTUAN UNSUR KELUMIT UMUR PARO PENDEK DALAM CUPLIKAN LINGKUNGAN DENGAN METODA ANALISIS PENGAKTIPAN NEUTRON

ABSTRAK
PENENTUAN UNSUR KELUMIT DALAM CUPLIKAN LINGKUNGAN DENGAN METODA
ANALISIS PENGAKTIPAN NEUTRON. Pada pcnentu:m konsentrnsi nuklida umur pamh pcndck di
dalam cuplikan lingkung:m dcng,m metoda analisis pcng,lktipan neutron (APN), sering tcljadi
kehil,ulgan cacall yang disebabk:m olch kccepat:m CilCiUyl ang tulggi. Suatu sirkuit clcktrik ., Pile-Up
Re.icctor (PUR)" diinstalasik:m ke dalam pencac:1l1an uklida umurpamh pcndck dengan spcktromcter
sin:tr-y sebagai korcksi tcrhadap kehilaJlgan nilai CiIC:lh CuplikaJl dimldiasi sclama 30 -60 dctik pada
fluks neutron 3,5 x 101~.cm-1s:1, kcmudi,ul didinginkan Selantil 120 detik d,m dilakukiul pencacallan
selanm 180 detik dengan menggunak:m sistem ini. Konsentnlsi nuklida di berbagai cuplikan lingkung:m
mcmpunyai hasil analisis y:mg berbeda , Icbih prcsisi dan akurJt, dim:ma harga pcngukuran dari :malisis
deng:ul sistem PUR 30% lebih bes,tr dari pada hasil pCnh'llkur.m dcng:m metode spcktrometri sinar-,
konvensional,
ABSTRACT
DETERMINATION OF SHORT-LIVED TRACE ELEMENTS IN ENVIRONMENTAL
SAMPLES BY NEUTRON ACTIVATION ANALYSIS. Concentrationo f a shon-lived trace elements
in environmental samples were detennined by neutron activation analysis, a counting loss often occurs
due to the high counting rate. A Pile -Up Rejector (PUR) electric circuit was installed in counting a
shon-lived trace elementsb y a y-ray spectrometeirn ordert o correcta counting loss. The samples" .ere
irradiated for 30 -60 secondsa t neutron flux of 3.5 x 1012n.cm-2.,s -th1e n the samplesc ooled for 120
seconds and counted for 180 seconds using this system. The nueclides concentration in the varieties
environmental samples have a difference anlysis results, was more accurate and precise, which the
measured results ,vould be 30% more higher by PUR system than the result would be counted using a
conventionaly -ray spectrometrmy ethod..