MCQ FRCR --PARTICLE INTERACTION

9.True regarding interaction

a.the amount of energy required to create an ion pair is about 34 keV

b.x ray and gamma difficult to stop being uncharged and zero rest mass

c.the beta particle has mass and is charged ,so stopped easily (by perspex)

d.protons and alpha particles are more massive than negative beta particle  and are charged( stopped by paper)

e.neutrons are more penetrating than proton ,being uncharged

ANS OF PREVIOUS BOG

569.Scintillators used in PET is/are

a.bismuth germinate

b.lutetium oxyorthosilicate

c.gadolinium oxyorthosilicate

d.sodium iodide

e.calcium zinc phosphate

569.abc----(Chapter 8, page no.134,second edition (2008),Farr’s Physics for Medical Imaging).

571.True regarding scintillation detectors

a.effective atomic number of bismuth germinate is 51

b.decay time of bismuth germinate is 300ns

c.typical energy resolution at 511 keV is 10%

d.decay time of gadolinium oxyorthosilicate is 60ns

e.effective atomic number of lutetium oxyorthosilicate is 75

571.bd----Effective atomic number of bismuth germinate, lutetium oxyorthosilicate, gadolinium oxyorthosilicate,sodium iodide  is 75,66,59,51 respectively. Decay time  of bismuth germinate, lutetium oxyorthosilicate, gadolinium oxyorthosilicate,sodium iodide  is 300,40,60,230 ns respectively. Typical energy resolution at 511 keV of  bismuth germinate, lutetium oxyorthosilicate, gadolinium oxyorthosilicate,sodium iodide  is 25%,25%,15%,10% respectively. (Chapter 8, page no.135,second edition (2008),Farr’s Physics for Medical Imaging).