The extensive air shower (EAS) development model independent method of the determination of a maximum depth of shower (X sub m) is considered. X sub m values obtained on various EAS parameters are in a good agreement

Dedenko, L. G.

Efimov, N. N.

Glushkov, A. V.

Makarov, I. T.

Pravdin, M. I.

English

NASA Technical Reports Server

48 HE 4.1-19
THE MAXIMUM DEPTH OF SHOWER WITH Eo> 1017 eV
ON AVERAGE CHARACTERISTICS OF EAS DIFFERENT COMPONENTS
A.V.Glushkov, N.N.Eflmov, I.T.Makarov, M.I.Pravdin
Institute of Cosmophysical Research & Aeronom_,
Lenin Ave., 31, 677891 Yakutsk, USSR
L .G.Ded emko
Scientific-Research Institute of Nuclear PkTsics,
Moscow, USSR
ABSTRACT
EAS development model independent method
of the determination of a maximum depth
of shower (Xm) is considered. Xm values
obtained on various EAS parameters are
in a good agreement.
1. Introduction. Investlgatioms of the shower maximum
d i i i,iiepth Xmare carried out at various arrays and by different
methodsbut the significant scattering of the obtained data_is still available (Table 1), A reason of most of discrepan
cles is mainly due to methodical difficulties associated
with the transition from the observed EAS parameters P=P(Xm)
to Xm. Thereby one had to use the theoretical conceptions on
EAS development difficult to test experimentally.
2. Method. We con- Table 1
sidered one more ree- l
thod of Xm deferral- Parameter E o Xm Worknation on th expe-
li ii ii 1 i i
rimental data ob- _ 1,6.10 7 660_50 [1]ai ed at the Yakutsk ......
EAS array. By compu- 1,@.1017 70Oz15 [2]
ter calculations such 2.1017 681+20 [3]parameters were found
which are the fumc- 1,2 •1017 706+36 [4] .
tionsof or (Q) 10176a0+20[5]P=P(X-Xm) type in wid_
limits of initial con- 1017 5_5+20 [5]
dltions: X=lO20.sec 8 • 1017 500_20 [5]The calculation were
carried out at var_ 2.1017 680_20 [6]
i i i ii i I ir i I
ious E o and e on LDF(Q) 2"1017 627Z-20 [7]
two, quite different
models of EAS deve- 1,5-1017 6.00_50 [8]i i i ii
lopment. The first _ C_ 3.1017 68_0 [9]
model corresponded L
toscali oJ,the 3.1017750Z30[9]
second one - to sca- LDF(_c) 3 "1017 609_3 [9]
ling at E<IO 1_ eV
https://ntrs.nasa.gov/search.jsp?R=19850027668 2020-03-20T17:19:15+00:00Z
•4 9 HE 4.1-19
EO, 25
[Io]andto_s~ rl_ , i_, , ,,at E >1101 _+ eV. The 3,5 --sc..r.
cross-sections in inelas .... sc _6.%-
tic processes on both 3%°i -_
models changed with en- 40°
orgy according to [101j. 3,0
The index of the LDF of f 160
electrons tie at the _° 320 "JD(R)~l_ne
distance interval It:200-6o0m
R=200-600 _ from the. 2,5 , I , J -
showerco_e ( _,,,,.,R..",') o_ 06 0,7 0,8.Xm/Xand ratios of densl_es
of the EAS Cerenkov
light to electrons Fig .1
lg{Q/_¢ ) and of elec-
trons to muons
lg(_¢/gM ) at R=300 m
were conbidered. The , ,I
above parameters are sa-
tisfactorily measured at --sc.ns"E_ _L
the Yakutsk EAB arra_ _ ---sc "_0 °(_e=_s-_,). i}_2O
3. Results. Calcula- ¢31c_' .32-_°
_ion results at Eo : _'_I,7
1017-1018 eV and e = /16;
16, 32 and _0° are shown , ' '
in Figs.l-3. From Fig.q S(_ 4_ 500 X-_m
it is seen that Ra is
unambigiously associated Fig.2
with Xm/X independently
of En, _ and characteristics of nuclea_ interactions. We
use _his peculiarlt7 of electron LDF to find Xm:
- ( Ire-2,,1,! ) X $/cm2Xm = 1,7 " ' " (I)
The obtained Xm {S \_ ' _
are given in Table 2. 16°\\ \
The parameter lg( G /"ofge-) i,_,'1,0 3_x_'Q
which is the function _ \ -,,40_
X-X m possesses the ana- C_-J_T, , _ \\\-
logous feature (Fig.2). c_ __ Sc+ns_Eq_S 32°
xm=x-_23(lggO,8B)_j. (2) O_"'-_, , , \"• 200 300 400 ,500 X-Xm
Fig.3
50 HE 4.1-19
Table 2
ig Eo 17,20 17,55 18,02 J8,_+2 J8,91+
X, g/cm 2' 1060 1060 1070 1080 1060
_ 2,57 2,60 2,70 2,78 2,,80
Xm+aX m 660__30 675+30 725+30 765+30 755+40
he 3,18 3,22 3,26 3,31 3,31
Xm+AX m 665+60 690_60 72(%60 760_60 750_60
1,94 1,91 1,79 1,71 1,59
Xm±AX m 615±30 625±30 685_0 730_40 760+__5
lS(@/Ne) 5,37 5,31 5,19 5,19 5,O
Xm+AX _ 640___0 665±40 725Z40 735+_40 800_0
lg EQ - 17,56 17,91 18,39 18,79
X, g/on2 '- 1090 1080 1080 1080
ig(_l_ ) - 0,76 0,82 0,99 1,04_
Xm±AX m - 670_20 670__20 715_20 725+25
ig(Ne/N_ ) - 1,17 1 ,I28 1 ;_7 115 _t
X_* A Xm - 665+_35 670_35 720+_35 735t35
As for lg(_ e I_M ) the unambiguit7 condition due to the
zenith angle is broken. Therefore the experimental and calcu-
lational data are needed to be compared at similar @
The averaging of data in Table 2 results in the follow-
ing expression:
Xm = (700Z_35) + (66±6)(lg Eo-18), g/cm 2. (3)
f
Note that all the above parameters were experimentally
obtained at fixed 9a (300) and calculations were also car-
ried ou_ under such-condition. If to make calculations at
fixed Eo, then Xm value becomes _ 50 g/cm2 less.
@. Discussion. The integral values lg(q ) /Ne) and
lg(Ne/N _) are close to the parameters lg(Q/9 e ) and
lg( _¢/_ ). Here _ is the total flux of t_@ EAS Cerenkov
ligHt_ -'_and N e are the total numbers of muons and elec-
trons. Their dependences on X-X m are analogous to ones pre-
sented in Figs.2 and 3.
Apply this method of the analysis of data to other ar-
rays. One can do it without additional calculations with res-
pect to the parameter lg( 9a/gM ) [9], since it is similar
to our parameter. Accordiz_ t6_[9] at R=300 m, Eo=I017 eV
and @ _15 ° we have lg(9¢ /gM )=0,3. _o recoum_ from 9c
measured at the Haverah Park array to _e at R-300 m we
5 1 HE 4.1-19
use the ratio 9a /9c_ 1,8 [113 . Then lg( 9,/9_ )_0,58 and
from Fig.3 we find Xm_ 620 g/on 2, i.e. much higher than in
Table 1.
. Conclusion. The analysis of various EAS components
ased 0n the method of "model independent" parameters yields
Xm=700__35 g/cm 2 at Eo=flO18 eV and at fixed _s(300).
References
1. Efimov, N.N. e_ al., (1983), Pro____c.18-th !CRC, Ban_alore,
176.
lm_kov, N.N. et al., (1979), Pro____c.fl6-thICRC, K_oto,
f/"
otheroe, R.J. and Turver, K.E. Nuov_.___oCimento, _,
(1979), 277.
4. Thornton, B. and Clay, R., (1980), P___.Rev.Lett., vol._5,
noue, N. et al., (1981), Proc.l_ ICRC, Paris, vol.11,
_ammond, P.T. st al., (1978), Nuovo Cimento, 1C, 515.
7. Dyakonov, M.N. et al., (1981),-_oc._ ICRC, Paris,
vol.6, 106.
B'=Tara,--_. et al., (1981), Pro____c.17-thICRC, Paris, voi.11,F
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_-_il a_-a_,A.M., (1979), Proc.16-th ICRC, K_oto, vo!.9, 15.
11. Kellermann, E.W. and Towers,--_., V_'g9),--_prln_,
Uni___/v.Leeds.


The maximum depth of shower with E sub 0 larger than 10(17) eV on average characteristics of EAS different components

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