Смелов В.В. Лекции по теории переноса нейтронов

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F(G)=.\

f(M)dG.

(2.2)

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pasencraa

(2.2)

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cnezryromee

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F (0)

(M)l

(2.3)

rne

M -

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rosxa-

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cnenyer

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H H3 (2

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MbI

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ne-

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ero

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(3.2),

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•

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113

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peneaeane

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as-

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paccesuas:

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ect»

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iot

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KaK

cneayer

onpenenenaa

(3.4),

paaxepnocrs

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[0]::::::

=1/[N

] = cM

•

§ 4.

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Paariepex

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pernenae

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noncxaxcer

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nyrs

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cr.

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npen-

nonar

aex,

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nornoutaer

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Flyers,

nanee,

:Ha

rpaas

nJIaCTHHbI

x==O·

naztaer

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(pac,

2).

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6bI

cpena

nornoutana

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1'0

nepea

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a HMeHHO'- 1

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nysxa

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rpana

X=O K

rpana

x=H.

060-

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1 cex nepecexatornax 1 CM

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tIaCTHOCTH,

/(0)=/0].

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<PYHKllHIO

I (x) -

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ceiitIac

nama

sanasa.

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pac-

cyJK,lI.eHHH

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paccaorpenae

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(!{), T. e.

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A -

ero

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3·

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pac-

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HeHTpoHoB,

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rpans

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x, T.

f,(x).

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(x) -

/'(x+ax)]!1

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ax)

- I

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ax+

aNI

(x) =

TIPH

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ypamrenae

dlldx+aNI

(x)=O,

oomee pemenae xoroporo

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BH)I.

(x)=A

exp

(-aNx).

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H3 yCJIOBHSI J(0)

T. e.

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exp(-aNx).

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Hac

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o.·B

caMOM

neae, eeJI'H B

q>OpMyJIy

(4.2)

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x=H,

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nJIOTHOCTb

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nJIaCTHHbl

nysxa

HeHTPOHOB

JI = J

(El)

= J.

exp

(-aNH).

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ecrs B03MO:>KHOCTb

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nynxa

11/10,

TO H3 nOCJIe,llHeM

$Op'MyJIbI

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0*.

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paCCMaTpHBaTb

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ceuenueu

(~a=N

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Os,

~f=N·(Jf).

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ceseaae

tIHCJIeHHO

rrpencrannaer

'C060M

CYMM3P'HYIO

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scex

anep

B 1 C.M

HMeeT

cnenyroutyio

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[~]

===

[a]

[N]

===

•

CM,-

===

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THnOn,

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cexenae

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~=NI01

...

+Nio

...,

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i-to

copra

B 1 CM

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cesenae

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nponeccca

AJIH

.9THX anep.

<POPMYJIY (4.2)

Tenepb

MOLKHO

nepenacars

B BIIJI.e

J(x) = J,

exp

(-Ex).

(4.4)

(4.5).

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CJIOH

semecraa

aeonaoponeu, HO

MaKpocKonlilIecKoe

cesenae

ecrs

$YHKUH5I

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nepexennoa

~=~

(x),

BMeCTO

<pop-

MyJIbI

(4.4)

JIerKO

yCTaHoBHTb

CJIe,llYIOIIl,ee paaencrno:

J(x)=J.

exp [ - i

(a)da1

nOJIYlIeHHble

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n03BOJIHIOT

BbIBeCTH

nexoropsre CJIe,ll.CT-

BHH,

xacro

acnonsayexsre B

ueHTpoHHbIX

sanaxax.

3TOMy

nonpocy

no-

CBHmeH

CJIeJlYIOIIJ.HH

naparparp,

§ 5.

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AnMHA

CBO&OAHOrO

npO&Er

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caona

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paCCMaTpHBaJiH

npenu-

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H npe,ll.nOJIOLKH:r.1,

lITO

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x=O

(CM.

pHC.

rranaer

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HeHTpoH.

ECJIH

HeHTpoH

nperepne-

saer

aaxaar

nJiaCTHHe,

paCCTOHHHe

KOropOM

norno-

maeTC5I,

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BeJIHt.IHHOM

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-rana, Taxyio-

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paCCMaTpHBaeMOM

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S»

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3).

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x=O,

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x H

X+IL\X.

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3Ta

Be-

pOHTHOCTb

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iJpe3BbIlIaHHo

JIerKO:

P(~x)===

[J(x) - J

(x+

~x)]IJ,

exp(-~x)

[1-

exp(-E~x)].

(5.1)

=19

<POpMyJIy

(4.3)

saute

scero

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He.

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2---301

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e ne

oseas

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a nOToMyo6blllHO npennoxararor _

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nOCJIe,llHHH,

no onpenene-

HHIO

(CM~

2),

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i(x).·

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(~x)

lim

(x)

- J (x +

~x)

- _

(x)"=

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(5.2)

~x~o

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Jo~x.

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sro

q>OpMyJIbI

(5.1) H (5.2). B pasnoa Mepe

cnpaaeaaaaa

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MbI

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nepeft.neM.

TIYCTb

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cpeau

(xoropym-caoaa

oy.neM

npeanonarars

TOJIbKO

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nanaer

nepneH){HKyJISIp-,

nysox

HeHTpoHoB

nJIOTHOCTblO

(pHC.

4).

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nOJIy6ecKOHeQHOA

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paBHoMepHblM

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B semecrso. Ilpennoaa-

ras,

lITO see

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pa36HTO

3JIeMeHTapHbIe

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(~i,Xi+·L\Xi)

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(Xi~Si~i+l),

f(x)

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(5.2).

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MeCTa

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(5.3)

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MeCTa

aa- .

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(5.3)

nO''BCeM

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)

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