Đề thi khóa 33 trường ĐHSP năm 4 khoa vật lý - Vật lý neutrong (2) doc

lnteraction of Neutrons lyith S{atter ilii: Probleml. , .l 'fwo beams of l-ev neutrons intersect at an angle of g0". The rJensity of neutrons in both beams is 2xlOrln/cm3. a) Calculate the intensity of each beam. , , . : , b) what is the neutron flux where trre bcanrs intersect? . t, Problem 2. A monoencrgctic bcam oI ttctrtrons- 4-x,1,1)t0 n/(s cur2). impingcs on a target I cm2 in area and 0'l ctn thick. fltcrc l'c 0.048xlOrt at.nrs p*r'.,n1'inir1.'l*e" ij rrr" total cross-section at the energy of the beanr is 4.5 b" a) What is the nracroscopic cross-section? I ,, r b] fg* llany neutron inieracti.ns per second occnr'in the target? : c) What is the collision den.sity lcoilision rate)? -: -*'bYr' Problern 3. The I entitter ]tat 6]*tr'tife 2.3 min) can he proclucecl by the raclioactive capture of , , neutronsby28Al.r.neo.ozs:-"V.,o,,-,ection1brjtlrisreactionis0.23b.Supposethata small,0.0l-g aluminurn targer is'placed in a beam "ro.ozi:-rv n",,r*i 3;jtF;i;;X rvhich strikes the entire target. Calculate: a) The neutron rlensity in lhc bcam: b) The *1r, which ttAl is produced. Problem 4. A beam of 2-l\'tcv neutrons is inciclerit on a.slah.ofJreavy.,r,r,';rter (D2o). TSe,totat;;:_!,i++ cross-section of deuterium and oxygen at this energy are z.iand 1.6 b, respectively. . , , a)Whatistlremacrosbopictotilcross.sectionofheavywaterat2MeV? ,)H:il*fk:rrrrsttheslabbetoreclttccthcintensity,ir.tr'"uncollidedbeambya c) If an incident neutron has a collision that it collides with deuterium? in the slab. r.vhat is the relativeprobability . 2. A monoencrgctic bcam oI ttctrtrons- 4- x,1,1)t0 n/(s cur2). impingcs on a target I cm2 in area and 0'l ctn thick. fltcrc l'c 0. 048 xlOrt at.nrs p*r'.,n1'inir1.'l*e". -: -* 'bYr' Problern 3. The I entitter ]tat 6]*tr'tife 2.3 min) can he proclucecl by the raclioactive capture of , , neutronsby28Al.r.neo.ozs :-& quot;V.,o, ,-, ection1brjtlrisreactionis0.23b.Supposethata. produced. Problem 4. A beam of 2-l'tcv neutrons is inciclerit on a.slah.ofJreavy.,r,r,';rter (D2o). TSe,totat;;:_!,i++ cross-section of deuterium and oxygen at this energy