The interaction lengths of energetic pions protons in iron

1 downloads 0 Views 2MB Size Report
4 ) G. IielletCiini, G. Coccc~rii,A. N. Didderis, E. Lillet:hriri, G. blatthiae,. J. I-'. Scaol.ou, m d A. >l.l\Tet;lereli, Nilci. Piiys. 2,609 (1966). 5) E. L. Androi\.ikashvJ.li, G.
.. ... . I

.

.

.

.

.

..

.. ._.. I

I

,.e.-.-. ,.,.':.: .a............ -: ...... ..:. ,r,.- . . . . .. . . .:,. . I

. I .

.

:

:1-

.

. . .

. . . . . . > . . , . . -. . .. .. ' .. .

.. " . . . . . . . . .

.

1 . ;

.- .

,,

. . . < . r . . . c.... . . . ..

,

e

. .

..

r

r

+

.*

.

. .. . .

.

,

.. . ,..

.

. 5 >.

I*

,.9

..

.

.

. .

,

. .

, . . ' .' , '.. . , . , . . . . .. .

.

>'

1: ,

,

.:

.

.'- . . .

.

. . .

.

.

.

-5­ Such e v e n t s

cosrriic r z y muons were i n c j - d e n t on t h c d e t e c t o r .

were rscl.ectcd by demnntllng t h a t a l t c m a tc end a f t e r eaci? of thc i-nodulea bein:,

poridirrg to t h e passage of a

II!GC:II~.CS

situated before

a n a l y z e d had pubes corre?R­

~i.1iglerelativistic

par'ticie.

a

!

P

I

I

. .

., .

. . ,

,

-

,

..,.

. .

.

..

. .

I

.

.

i

,

. . . I

.

'. .

_. a .

.

I.

i

.

,

',

.. :,: . .. . . . . . . . ... .. . . . .. ,.. ... (...

..?

.

.:.. i

.

.

,

. . ..

, , ' . '

. . . . .... .

..

. .. . . . . . .

.

.

. . .

. . . . 1

.

,

..

..............

.. . i.

. .

.< .... . . . .

. %

.;

.,

-7­

.J r

.

.

-a-

I

4.

. _ )

I

I

.-. ....''IC

.1 ,,

Y .

I .



I

.~~'t..':, -:1

..

. .

. . . . .. . ....

........ ' .,/ .... , .I

I

.

. .

. . _

, . .. .., . ....

,. h

..

.. .

,.

,

.

..

.. .. . .. .. . L

;

_-. ,,*

',

. . . . . . .. :/. ...........; . . . i

.

.

,

.

. . ...

.

.~ ..

..

, .

.......,,., . . . . .

-9­ e x p e c t e d response of tlic d e t e c t o r s ai.c+ r e q v i r c d t o d e f i n e nu i n t e r z c t fori, as a r i m c t i o n of the l>;.ri?her of equ:vxl.cr.c

m u m s nerdeti

LO

def:i.nc an i n t e r a c t i o x , and 2 s i!

f u n c r i o n of ({I f f e r c n t niiubers of rnuoii ec!uival.ent p a r t l c l c L s i n t h e f i r s t a n d secnn,:; k t e r a c t i o n I.iod(!lcs. The s l o p e of t h e i i l t i x r a c t t o n c u r v e was c a I . c u 1 a t e d f o r s e v e r a l

d i f f e r e n t r m s u s i n 3 the rcqijj remcdnt of

OLILIJI~~Sexceed

i.i~g3 th!-i.shoId

i r o x two o r tl?;::-*c c n n s c c u t i v e modules t o cicf-ine a n I n t e r a c t i o n .

For e a c h

ILUI

t?i~ slopcs d e t r m i n e d using

t h e r e q w l - c e m ~ n t o f two

c o n s e c u t i v e nIodul.es a g r e e d we1 1 w i t h i n the e x p e r i m e n t a l u r r c e r t a l n t i c s w i t h the s l o p e s d e t e r m i n e d u s i n g t h e rcquircment of t h r e e c o n s e c u t i v e modules.

1Iowcver. :he

module measui-cnents

s t a t i s t i c a l a c c u r a c y a s s o c . i a t e d w i t h t h e three

i . 7 3 ~

somcvhat less.

T h e d a t a from m e l e s s module

. .

I

I

1111 I 1

I mmm1111.111.111.11-11

1111

.

... .

.

. *.

. ,, .=. : .' . _ . . . . ... . .

:*. . . .. t

.

,, . .L ...:.

I

.

.. . . .

,.... ;. :.... .'

;.;, '. ,. : I::'.,., ' 1

.,

8

.

.

'..

. .

.

.

. .. . . .

.

. .

. .

.

. . .

. .. . . .

*.

!

I

.

.

.'

~

. . . .. . . .

'

-14­ c o u l d be used s i n c e the nuzhcr of i n t e i - a c t l o n s o c c u r r h g i n t h e n e x t - t o - 3 . a s t m o d u l e o b v i o u s l y c o u l d n o t be d e t e r t n i n e d w i t h t h e s a n e r e q u i r e m e n t s p l a c e d on t h e o t h e r modules.

The l o s s

of i n f o r m a t i o n wl?Fch m i g h t h a v e been p r o v i d e d by t h i s one

a d d i t i o n a l rnociule in-rceses ?lip

F t atist-f.cn1.

urcertninly.

Sir\ce

t h e d e t e m i n n t , . o n of t h e sl-ope was irrdcpe1;cient of whet.iier tile t w o ~ , rt h e t h r e c c o n s e c u t i v e - ~ i i o d u l e rcquirc.i:~cnt w;?s u s e d , nrid b e c a u s e g r e a L e r accurac:r

a c h i e v e 3 r i i ~ l . , t h e two m o d u l e requirc,i:icnt , all

1~7as

s u c , c c e d i n g detc.m.inat:.oss

x;-:Ye

n a ; ! ~w 3 . t h t h e

r e q u i r e m e n t t h a t LWO

c o n s e c u t i v e modiilcs had o u t p v t s w l i i c h a c c e d e d t h e s e l e c t e d t h r e s l i o i d s .

'&e :hrcuhold F'-.2y:iicol

t o define! a n i n t e r a c t i o n s e l e c t s t h e

c:hoscn

processi'r; t o L e observr:i.

a n i n t e r a c t i o n is i-.-.is>d, and a l s o f a i l t o ckvei.c;>

As tllc rlirc~sho1.df o r t i e t ~ . ? r . ? : \ j n ~

I n t r r s c f % o n s w h i c h h a y e low i r i i i l t i p l i r i t y ;?

s i g n i f i c a n t s h ~ i i e rare n o t d e t e c t . e 3 .

However, i n t e r a c t i o n ; v i t h tilgh n u l t i p l L c i t j 7 w i l l c o n t i n u e t o be detected.

bIost i n t , e y n c t i o n s in

1.JhiCh

u ~ i eo r i-iore n o ' s a r e p r o d u c e d

w i l l a l s o b e d e t e c t e d d u e t o ? h c r a p i d b u i l d - u p of t:he eZI?cf:.ro:nag11cCic shower f ~ l i o w i n gt h e d e c a y of t h e n o i n t o t v o p,ciii:~iar;;ys.

A t the

e n e r g i e s i n v e s t i g a t e d i n t h i s work, higher :nultfpl.icf.ty e\Wnts have

luwer p r o b a b i l i t i e s .

S i n c e f n c r e a a i u g tho t l i r e s h o l d r e q u i r e i u e n t will.

5

b i a s ag.r,ins t some l o v m u l t j . p l . i c i t y , higher: p ? : o b a b b l i t y e v e n t s w h i l e continuing t o s e l e c t ti?: h i g h multtplicity, l o w e r p r o b a b i l i t y e v e n t s , t h e i n t e r a c t i o n l e n g t h i s e x p e c t e d t o r i s e a s a f u n c t i o n of i n c r e a s i n j ;

threshold l-'.'quirCnient.

F i g u r e 3 shotis a p l o t o f t h e r.ie.asured i n t e r -

e c t i o n l e n g t h f o r b o t h 9.3-GeV protons a n d positive p i o n s a s a f m c t i o n

b

,

,

...................

. . .

.

.

.

'

. . .. .. .. . .. _. . . ... .

.

.

.

....... :-.,..,*:

..

. I

:...

.._....

. _ . . . ..

.

... . .

,

.

.

.

. .

.~

.

. ­

. . . . . " , . .. . . ._

. . .

_ .

,

-15­ of the t h r e s h o l d .

The i n t e r a c t i o n l e n g t h is seen t o 3.ncrease

5y a b o u t 202 a s t h c t h r e s h o l d reqlij.i:ement Is r a i s e d f:rom 2 t o 7 s i n z l e p a r t i c l e equivalents. .

The m e a s u r e d i c t e r a c t i o a l e n g t h

seems t o rcaiain r o u g h l y cow;tzn(l o r dcc.rease s l i g h t l y f o r still

the thresho2.d i s l o x e r e d t'o o n e I o n i z i n E p a r t i c l e the i n t e r a c t i o n w i l l .

3ln:os.t s l w n y c b c d e t e c t e d in thc f i r s t few t u n g s t e n rriodules and no usctfu:! d a t a f o x t!le d e t e r i n i n a t i o n o f t h c ! s l o p e i n t h e i r o n n l o d u e l s w i l l b e a v t i lI n h i e . Not: much d a t a a r c d v n i l a b l c f o r t h e partic1.e 1 n u 1 t i p l i c i t i e s !.o

he e x p e c ~ e dfi-om iiuclt-ar i n t c r c c t i o i i s In i r - c n a t t h e t i g a t e d i n the p r e s e n t w o r k .

was detcrririncd for

ii

,

: . e r g i e s irives­

Thus t h e J r i t - c r a c t t o n in3a.n f r e e paell

r a r g e of vnl.ues of the tlirc:,hcl.ds,

F:r,urc

4

s!lous a p l o t of the stntlsticnl u n c e r t a i n t y i n the ine.ln free p a t h

a s a f i i n c r i o n of t l i r e s h o l d . in

t . 3 ~p e r c e n t a g e

F o r t h e s e L9ta there i s

B

very clear rniriimum

u n c e r t a i n t y f o r a t h r e s h o l d r r . q u i r a n e n t of 3 . 0 muon

equival.ent p a r t i c l e s .

The o t h e r d a t a ( 1 3 . 6 and 1 7 . 8 - C e V p r o t o n s ar.d

9.3-GeV p i o n s ) a l s o chow a minimum i n the u n c e r t a i n t y at a thresLo1.d v a l u e of 3 . 0 muon e q u i v a l e n t p a r t i c l e s a l t h o u g h i n t h e s e latter c a s e s

.

.. .. . . . .

.

.. c .

I......'.. . . . .

. .

r

!:: _. '

'

: ; ; -

.

I

.

.'

.

i

'

,

. . . ... . . . . . I

,.

.

c

-

.

.p.:

I.'-'

., - ,, .._. . .>. . - - -. ... . . .\'". . ._ .,.,,. .

'

.

._

-:..' . ~

. .

.:

I

\

.

_ . . : ., . . :, . :, . .

..:

..

.

..

, '

_._

cases t h e m i n i m u m FE DO^

...

. ....

1

.(' ,. .

... .: ...........

'. .

....

_.

.

..

.

. .

. . ..

.I... I

I

RO

I . , . .

.' . .

.. .

. . .. .,. ,

. . .

i,il

.. , .

.. . . . .. < . ,.

. .. . . . . . . . . . . . . . . .. .. . .. _. . .. .. , . .. . . . . . . . . . .. . . . . .. ,.

. I

._ . r .

..l

I

.

,. . ..-

... .

......

-0

1

. . .

.

.:

.. . . . .

.

..

.

. . ......

prcnounced.

Thfo minfmum in the

u n c e r t a i n t y o c c u r s e v e n though t h e total nuniber of i n t e r a c t t o n s f o u n d i n t h e iron modules is a r i ~ o n ~ i t c ~ ~ l ~i nacJr.el e>s~i n g f u n c t i o n of t h e t h r e s h o l d value u n t i l t h e t h r e s h o l d i s approximately muor, e q u i v a l e n t psrti c l e s .

of t h e s l . o p c dep'ndc;

,

e

The u n c e r t a i n t y In ti-.e d e t c n ; i n n t i o u

j o t t i Eycn t h e s t a t i s t i c a l a c c r ; r a c y of t h e d a t a

of the. fit b c c o x e s worse r~P1il.et h e t o t a l number 02 interastdoum 12

detccLcd i n c r c a s c s , i n d i c a t e f i

tliitt

data f o r t h e s e I i i g h e r t h r e s h o l d s

d o n o t fit t h e Iiypot.Ires5.s of a slmplc e x p o n e n t f a l d e c a y

60

well.

The

thresV.old w?:fch result:ed f n Che rinimum s t a t i s t i c a l u n c e r t a i n t y i n h was

Ci1092Ll.

f i r s t a t 3 was i n v e s t - i g s t e d .

For some cases, p a r c i c u l a r 1 . y f'or F n t c r ­

a c t i o n s ~ I i i c hi n i t i a t x r.Icctro,r.apriet-j.c c a s c a d e s , t h e s i g n a l 3 . c u e l i n t h e s e c o n d r!oJul.e is h i g h e r t h a n i n t h e f i r s t .

I t was t h o u g h t t h e t a. h i g h e r

t h r e s h o l d f o r d e t e c t i o n i n the scdcond module would niare n e a r l y r e p r e s e n t t r u e e v e n t s and b e a b e t t - e r c r i ' ; e i - i o n f o r e v c n t s e l e c t i o n .

The G a t s f o r

9.3-GeV I . r o t o n s were a n a l y z e d b y v a r y i n g the t h r e s h o l d f o r t h c s e c o n d module from 1 to 5 muon e q u i v a l e r t t p a r t l c l e s u ' n i l e t h e t h r e s h o l d fox t h e f i r s t module w:i.s he1.d const:int: a t 3 muon e q u t v a l e n c p a r t i c l e s .

As

can be seen in F i g . 5 , the,miniuwic n n t e r t o i n t y irk t h e d e t e r c n i n a t i o n 02 t h e s l o p e o c c u r s with t h e same threshold f o r b o t h the f!.rst

While a d j u s t i n g t h e t h r e s h o l d v a l u e in t h e second nodule changed

modules.

I

and s e c o n d

~

I

i n the val.iie of t h e i n r e r s c t i o n 1 9 n E t h was c i c t a c t c d . f i n a l . results on t h e d e t e r m i n a t i o n

0%

Thus all

inzeraction l e n g t h s presented

h e r e arc b a s e d on the +cqu%reinent of Erao s u c c e o s i v e t n o d u 1 . e ~wlth n

.. .. l e n g t h s c o n ; sins

33

addit:cna9.

212 duc t o the i i n c a r t a i n t y

I m c e r t d n t y of

i n t h e mean d r : i t ; i t y of the d e t e c t o r r w i t < : r i a l . I t iiccds t o be r;ti-c~-t~,Jy strrriscd ( h a t .

Crt

of ';he i n t e r a c t i o n I . o n g t h s , ~ n c i t h e c!;:;ucia'ied

Tables '5

uncert:lfnti.es

f o r o u r bast-fit d c f i n i t - i m o f an i n t - c r n c c j o n p a r t i c l e s i n esch of two consecutive?

aiid

nodules).

(3

ill\iarl

T I the values are givcri

equf.vnI.cnt

As �.a:; beezi d i s c u s r ; e d

f

p r e v i o u s l y , the value of the i r t e r a c t i o n 1eiigt.h c a n b e chenged coil , d e r a b l y

i o u t s i d e t h e s t a t e d e r r o r s by a p p r o p r i a t e changes i n the d e f i n i t i o n o f a n interaction.

,

The m e a n . h t e r a c t i o n l e n g t h s are o b s e r v e d t o b e i n d e p m d e n t .

of the nnmber of i r o n m o d u l e s eniployed to

tl! :'niii

t h e s t a t i o t l c a l uncer­

1' t

i

.!

.'i.

t a i n t i e s i n t h e measi.tre,..srit.

No s i g n j . f i c a n t d e p e n d e a c e of t h e i n t e r a c t i o n

I -18­

t

l e n g t h on energy is d e t e c t e d .

On t h e h y p o t h e s i s t h a t the i n t c s ­

a c t i o n leiigt?: i s i11depe12dcilt of eneirgy '?

P = 0.95 f o r pions.

0.0s f o r p r o t o n s azrd

The mean interection l e n g t h f o r pions 10

apprc)xi.wat
L:.

, the sinal1 c h m g e I n incidrnt errs-rgy s h o u l d not a p p r e c i a b l y a f f c c t the dctcr".nation

of t h e n3ari I n c e r a c t i o i i l e n g r f i .

Contiiiilination of t h e p r o t o n b ? m by o t h e r hadrons was small.

E f f i c i e n c y for r e j e c t i o n of n m.d K was metlsurc.d t o b e Getter t h a n

V

Ilieao4s

98M.

by t h e gas C e r c ~ k o vdetector

S i n c e thc f l r i i c of p r o t o n s nlriays

represented inore than h a l f of the trJtal f l u x , t h e c o n t a m i n t i t i o n in t h e p r o t o n beam w a s R l w i y s less than 2%.

,

-19-

1

-

:.

- .

.

.

.

..... . . .

5 -

I

. . .

.

. .

.

._. . .:..,

.. . . .. . . . . ,-: i . . :

,

I

.

.

.

. .... . .... . , . . . , . . . . . . .'

.. . .

-

.

:_

I

. .

,

.

-23­

runs was p l o t t e d a s a f u n c t i o n of module number. included i n the data a n a l y s i s the

flu!\

For e a c h module

of t h e i n t e r n c f i o n s d i f f e r e d by

no m r e t h m 2'% from the e x p " c t e d f i t ts t h e d a t a .

We t h u s c o n c l u d e

t h a t all detecLoro have t h e s'me e f f i c i e n c y f c r t h e d e t e c t i o n of an i n t e r a c t i o n t o wfthin a fer4 p e r c e n t .

S e c o n d l y , t h e muon e q u i v a l e n t

p a r t i c j . e c c ; l i b i n t l . u n fcjr thc? first u s e f u l i r o n iitodule wzs a r b i t r a r i l y

val.ue o b t a i n e d d e g e n d s somewhat upon t h e s i g n a t u r e required t o d e f i n e ..

....

an i n t e r a c t i o n .

C x a c t comparl. son v F t h t h e o t h e r aetcm.inot.i,oris air

L\\C

... . .

.i

O v c n t s , the precision of t h e p r e s e n t ircsiil.ts i s g e n c r n l J y g r c l n t t r . 140

s t a t l a t i c a l 1 . y s j g n J . i i c o n t \TarjotLon of

t h e mean i n t e r a c t i o n

l e n g t h f o r p r o t o n s o r p i o n s as n f u n c r i o r i of c?ncry;y 'i.:as ...

. .

t h i s work.

observed i n

Hoxcver, w i t h o n l y two exccptl.onr;, the d a t a p r e s e n t e d i n

T a b l e I11 r;how a , 2 y s t e m a t i c 5% d i f f e r e n c e berween measurements of the mean

:-?! . L

i n t e r a c t i o n l m g , t h made w i t l i cofimic r a y s and t h o s e i n a d c w i t h a c c e l e r a t o r

:.i

produced p r o t o n s .

A c o n - e c t i a n f o r p i o n cori: m i n a t i o n i n t h e cosinic

r a y f l u x ~ i o u l dlower t h e v a l u e o b t a i n e d

111

u n c o r r e c t e d c o s m i c r a y experi-

- .. . .. . ,

I

-._,.,, ... - . . . . . . -;. .

-

*:.-;..L

.

.

.

. . . .

.

.

..

'.

./, i

.

,

-

. .

-.

/.'

I

r

-

:


xim2nko, A . E . Piorosov, A . G. P:o7.ikov, 0 . F. Ogurzov, V. S . P~:chkov, D. 1'. X.3!l.l\Tet;lereli, Nilci. Piiys. 2, 609 ( 1 9 6 6 ) . 5)

E. L. Androi\.ikashvJ.li, G. 2 . C h i k o v a n i , D . I . G a r i b a s h v i l i , G a b u n i a , Li. B . K a l c a v r i d z e , D. M. K o t l y a r e v s k i , 2 . S h . N a n j a v i d z e , L. .4. R a z d o l s k a y a , and E . N. S h e r e r , Can. J . Pliys. 3, S 6 8 3 ( 1 9 6 8 ) . L . I,.

14. N. K o i i > J s h v i l i ,

6 ) W. ZG

H . Schniidt. (Dissertation Glcl. < 1 ? 6 8 ) unpublis!ied:.

1;.

-

Christlan-Albrcchts

-

Universitat

7 ) W. V. .Tones, K . Pjiikau, U. P o l l . v o g t , W . K. 13. S c h m i d t , R r i d 1.: W. Hi!:;i;ett, A c t a k'liysics H i i n g a r i c a ? 2S u p p l . 4 , 5 2 1 ( 1 9 7 0 ; Nuovo' CFciento Ei;, 5 7 5 , ( 1 9 7 2 ) . L

8)

G. L. Bashi!i~lj!i;;g;.an, V. X. Isclokopytov, P.. I . Demimov, V. S . Muryin, L. I. S a x y c i : c v a , a n d N . E . S i n y o v , p a p e r HE-24 1 2 t h I n t e r n a t i o n a l Co;:ference o n Cosmic i i x y s , H o b a r t , 5, 221.1 (1971).

9)

I,. Id. J o n e s , A . E. L'u.c sta n, G . 1). Dtt!eestel-, R . C!. Loo, D. E. Lyon, 1'. V. R m a n a Eiurthy, 1:. 17. K n t b , .'1 R . VJsliwanath, J. G. L e a r n e d , 1'. D. Reederr, l?. J. Wilkes, IC. N. E r i c k s o n , E'. E . Mllls, a n d D . Cork, L h i v e r s i t y of Michigan R e p o r t HE 71-46 R e v i s e d ( 1 9 7 2 ) .

b

> I

i

IE

I i

i I

,

1

i p

i'

-

lo)

J. F. O~?r,cs, V. K. Ualasuhrnhiiianpan, R. D. P r i c e , 14.. 2 . Ryan, a n d K. F. S i l v e r b e r g , I E E E ?cans. Nucl. S c i iL2, 1 7 (1970).

11)

W . V.

12)

El. W h i t e s i d e a n d J. Golluhy, Nuovo C l n i e i t o 5 4 , 537 (19S8).

Jones ( p r i v a t e c o m m u n i c a t i o n ) .

13) A . R a r b a r o - G a l t i e r i ,

S . F. Derenzo, L . R. P r i c e , A. R i t t e n b e r g , A . 11. R o s r a f c l d , N . B a r a s h - S ~ . h m i d t , C. Ericrnan, M. R o s s , P. S o d i n g , C. G . Wohl, Rev. Ploci. P h y s . 42, 8 7 ( 1 9 7 0 ) .

._.

._

14) L. J a n o s s y "Thew-y and P r a c t i c e of t h e E v a l u a t i o n 3f Measuremen t s ' l Cl;*rendori P r e s s , O x f o r d (iY 05)

.

15)

S. P. k n i s o v , S. V. Donokov, Y u . P. Gorin, A . I. P c t r u k h i n , Yu. D. Prokoshkin, D. A . S t o y a n o v a , J . V. A l l a b y , a n d G. G i a c o m e l l i , Pliys. Lett. 415 (1971).

s,

1 6 ) J. V. Allaby, Yu. 8 . E u s h n i n , Yu. P . G o r i n , S. P . Denisov, G. G . i ~ ~ ~ ~ A.~ ~I?.~ D c i ~d dle nl s~, , R. ti. Dobinsoil, S . V. Donskov,

A . K i o u i - i n g , A. I. I ' ? t ~ " ~ i k h i n ,Yu. U . Prc\kosh;:iii, C . A . S t a l i l - H r a n d t ,

D. A . Stuyanoi-2, and R. S . S h u v a l o i r , S o v i e t J . N u c l . P h y s . 7.3

295 (1971.); Y z d . F i z . 1.2, 5 3 8 f 1 9 / U ) .

17) F. A . f!ai-ris, S. I. L'arker,

V. Z. P e t e r s o n , Ii. 1:. Y o r m t , niic! !4. L. SLcvenson , N a t J o n a L A c c e l c r a t o r L a b o r a t o r y R e p o r t TM-3S8, 2610.90i) (1972)

.

I.

I

. -

. . e.

.

,;--

,

­

.

. .,I

',,,' ' . .... . ..r .: : .......... ' I

. .. . .

,. I..'

'

'

:. '2*-:

. . . .e r .

.

'

.

\ : , . ., . ., ., . .: .

..,

.

. . .

.

.

. .

.

.

. ...... I,.

..

I.

I

.

r.

Fig.

1

A scliematic Y i o n i z a t i o n calorj.meter tlsed i n i h i s e x p e r i n t e n t .

Fig.

2a

P l o t of p u l s e l i e i g h t a s a f u n c t i o n of module number. Xn [.his c a s e t h e modr8l.r i n which the i n t e r a c r i o n o c c u r r e d i s clc-ar1.y Fe 3 .

2b

Fig.

3

P l o t of tlie nicasurrid i n l c r a c t i o n i c n g t h as a f u n c t i o n of t h r e s l i o l d r e q u i r e m e n t s .

Fig.

4

P l o t of st;r?-isti.cnl uncertainty i n the determination of the m(!,ln i n t e r a c t i o n l e n g t h as a f u n c t i o n of threslioid requirement.

Fig.

5

TaSlz I

.

.

.

. :.- .

'

. . . .

3.3

23.0 151.4 a5.1 -4.7

1.3. P

-+3.0

: li.8 17.5

5

i 9 I

3137

133.0 24.1

C2.9

I

-+2.8

140.2 '3*2 -3.0

-+ 2.2

~

1.1

.

.

'. L, . '.. ,. . . . . '.;.i! ;. ."

L

. I ) < . -

,

,."

...

i,.

.

r

,,,-:,.

. ­

.

.

.. . ... . . ... . ..

. . ..:.. . .

i,

.

,

2..

. . . . ,

,

.

-

. ;.

,'. :'

.

..'. 5­ . :

,.

i , 1

._ . . . . . .

.

.

.... .

.

.

'.:

I

Table I1

&an

I

I n t e r a c t l c n Ler?~rkhsof Picns in Iron

A in p.lm2

1'1.8

1

9

I G X / A :i

Percent

, .

..

..- . . . .

\. . .. .. r'

,.

..

~

. .

F

.,

.,

.

'i-

..a,

.

..:..;

i.. .o

.

.. . . . . . . .

.

'.' .' ,..

:.I

_..:

4,

Table III

.

.. . . ...

Compariscn of E x p e r i c e n t a l 3 e t e m h s t i o n s of K c a n I n t e r a c t i c n L?;..gth.-, of %rr;tcm in Iron

. .

.

. .

-

.

.

.

.

, .

.

\

1 . .

.* . .

-

. . ' . . ., ' . _ .

': ... .:' : ... ;.-,

..',:.

..

. .. .. .

%

/.,

,,

c3.e rp.7 -J

Experirenters

i

(G3V)

A ? h o r e et al.(c) (1960)

24.2

C C S ~ i Ch ? y c

Accelerator

Bellettiai e t al. (1966)

(4

Cosmic Xays

.

15227

I n t e g r a t e d a l l ha-'-ons i n cosiilic r a y f l u x ( b ) TJalue i n t e r p o l a t e d from measurezents O i i A I and Cu

.

.

.

. . . .. .. . . .

I n t e g r a t e d all kxdrons i n ccsz1j-c r a i f i u x ( b )

I

.

...... '\.

.

.

c

. . . .. . . ... . _. ,.

. .

.

..

.

.