ThevalencechangesofdopedsamariumandthecreationaswellastheannihilationofF-centersintheprocessesofthermostimulatedluminescence（TSL）andphotostimulatedluminescence（PSL）ofBaFCl∶Smcrystalhavebeenstudied.AsbeingirradiatedbyX-ray,alargenumberofelectron-holepairsarecreatedinthecrystal.Mostoftheelectronsmaybetrappedattheanionvacancies,producingF-centers.Thedopedsamariumions,whichexistedmostlyintrivalentstate(Sm3+),maycapturetheholesandconvertthemselvestotetravalentstate.SothatpartoftheincidentX-rayenergyarestoredinthisnonequilibriumsystem.Onopticalandthermalstimulationthestoredenergycanbeliberatedasacharacteristicemissionoftrivalentsamariumion.ThisemissionoriginatesfromtherecombinationoftheF-centerelectronswithtetravalentsamariumions,i.e.theF-centerelectronsmaybeexcitedtotheconductionbandbyopticalorthermalstirnulationandthenrecombinewithtetravalentsamariumions.ThisrecombinationmakesthesamariumionstobeinsitureducedtotheexcitedstateofSm3+,andgivesrisetothecharacteristicemissionofSm3+.Ontheotherhand,duringX-irradiationafewelectronscanbetrappedatthesitesoftrivalentsamariumionsandreducethemtopalentstate.ButtheformationofpalentsamariumOnX-irradiationisverysmallascomparedwiththatofF-centersandsotheirinfluenceonthePSLandTSLcanbeneglected.
