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