Energy spectra for primary cosmic rays C-Fe above 20 GeV/n were measured on a balloon flight from Greenville S.C. in June 1982 with a hybrid electronic counter-emulsion chamber experiment. Fluxes above the atmosphere appear in general agreement with previously published values. The heavy events included in this data will be used along with the JACEE passive chamber data to provide a heavy composition direct measurement from 10 to the 12th power to approximately 10 to the 15th power eV total energy

Burnett, T. H.

Dake, S.

Derrickson, J. H.

Fountain, W. F.

Fuki, M.

Gregory, J. C.

Hayashi, T.

Holynski, R.

Iwai, J.

Jones, W. V.

English

NASA Technical Reports Server

OG4.1-9
$2
PRIMARY COSMIC RAY SPECTRA IN THE RANGE 20-60 GeV/n
The JACEE Collaboration+
h b f d f
T. H. Burnett . S. Dake , j. Derrickson , M. Fuki , W. Fountain,
D g l .n
J. C. Gregory , T. Hayashi , T. Hay_shl , R. Holynskl , J. Iwai ,e l n £ e
W. V. Jones , A. Jurak , Jy J. Lord , C. A. MeeganL, O. Miyamura ,c a n a
T. Ogata , T. A. Parnell , T. Salto , S. Strausz , T. Tahukl ,
Y. Takahashif, T. To_inagac, j. Watts _ B. Wilczznska_,
R. J. Wilkesn, W. Wolter l, and B. Woslekl
_nstit_te for Cosmic Ray Research, University of Tokyo;
K2
Department of Physics, Kobe University;
CDepartment_of Applied Mathematics, Osaka University;
_Okayama University of Science;
eD_partment of Physics and Astronomy, Louisiana State University;
Space Science Laboratory, NASA Marshall Space Flight Center;
gD_partment of Chemistry, University of Alabama, Huntsville;
Visual Techniques Laboratory, University of Washington;
iInstitute for Nuclear Physics, Krakow.
+Japanese-American Cooperative Emulsion Experiment
ABSTRACT
Energy spectra for primary cosmic rays C-Fe above 20 GeV/n were
measured on a balloon flight from Greenville S.C. in June 1982 with a hybrid
electronic counter-emulslonchamber experiment. Fluxes above the atmosphere
appear in general agreement with previously published values. The heavy
events included in this data will be used along with the JACEE passive
chamber data to provide a heavy composition direct measurement from 1012 to"
10--eV total energy.
INTRODUCTION
The JACEE collaborationhas been using emulsion chambers since 1979 in
a series of balloon flights to measure the composition, energy spectra, and
interactions of energetic (>I TeV/n) cosmic rays. The apparatus used in
JACEE's 0,1,2,4,5 have been largely passive, events being detected by the
development of dense electromagneticshowers which produced visible dark
spots in x-ray films. In 1982 a different kind of experiment was flown by
the collaboration. This incorporated electronic detectors mounted above an
emulsion chamber. The counters were used to define the charge and energy of
incident primaries and provide trajectory information so the primaries could
be traced through the emulsion chamber from the top down. For heavy ions
this has proven to be an efficient process, and the results of measurements
on -130 heavy interactions (Z_22) at primary energies >20GeV/n are described
at this conference.
. . 
J. . 
W. V. 
3  
M  I        e /  
 A E ol ation+ 
     
ur ett g . a  , ~  erricksong , . i , i ~  re ry , . aYrs i , . ayag i , . ol p i , J. I ai C 
Jones , A. Jurak , J oc J. Lord , C. A. Meegan h' O. Miyamura , 
C 1.   T. gata, T. . arnell , T. aito , S. Strausz , T. Tabuki , 
. akahashi f , . ottinagaC, J. atts g, . ~ \ 
. . il es , . olter 1., a  . osie  1. 
~nstit~te for Cosmic Ray Research, University of Tokyo; 
epart ent f hysics, e niversit ; 
'bepartmentpf Applied Mathematics, Osaka University; 
e 1) a a a niversit  f cie ce; 
rpart ent of Physics and strono y, ouisiana tate niversit ; 
ace cie ce aboratory, S  arshall ace li t enter; 
gDfipartment of Chemistry, University of Alabama, Huntsville; 
isual ~ s aboratory, niversit  f ashington; 
1.Instit te f r uclear hysics, ra . 
Japanese- merican ooperati e ulsion xperi ent 
T 
er  s tra f r rimary c s ic rays - e a e  e /  ere 
easured on a alloon flight from ree ville .C. i  June 1982 it  a rid 
l tronic t r-em lsion c a er rim t. l es a e th  at s ere 
r i  r l reem t it  r i ly lished l .   
e e ts included i  t is ata ill be used along it  t e JACEE assive 
chr~ber data to provide a heavy composition direct measurement from 10 12 to-
10 eV t t l e erg . 
NTRODUCTION 
e JA E llab ration as ee  sing e ulsion c a ers since  in 
a series of balloon flights to easure the co position, energy spectra, and 
i teractions f r tic (>1 e / ) c s ic r s. e r tus sed in 
J 's , ,2,4,5   l g ly ive, t  i  t ted  th  
lopm t  dense lectrom tic s hi  ed e  
s ts i  -ra  films. I  1982 a ifferent i  f e erime t as flown by 
the llab r tion. his i c rp rated l tronic t tors ounted above a  
e ulsion cha ber. The counters ere used to define the charge and energy of 
i ident ri ries a  r ide trajectory i formation so the ri ries c l  
 traced t rough th  ulsion r from th  top . r  io  
t is has proven to be an fficient r cess, and t e res lts f easure ents 
on -130 heavy interactions (Z~22) at primary energies >20 e /n are described 
 s ence. 
G4.l-  
https://ntrs.nasa.gov/search.jsp?R=19850025702 2020-03-20T18:03:24+00:00Z
OG4.1-9
33
The primary objective of this experiment was to obtain a statistically
significant sample of heavy ion interactions in the energy range 20-60
GeV/n, below the energy range of detection for totally passive chambers.
Other objectives were to allow direct calibration of some techniques used in
JACEE, albeit in a lower energy range than the other experiments. The
electronic counters also allowed the direct measurement of heavy primary
cosmic ray fluxes in the range 20-100 GeV/n (1-5 TeV total energy for Fe)
foe comparison with the other JACEE direct composition measurements above 1013
eV total energy, (see paper 0G4.1-13 this conference). In this paper we
describe the measurement of the abundances and spectra of elements from C to
Fe above 20 GeV/n.
Experimental
The apparatus was previously described (Ref.l) and is only briefly
reviewed here. It consisted of two solid Cerenkov counters (Teflon and
lead-glass) which were in saturation at the energies reported here and
provided primary charge definition; a gas Cerenkov counter (i atmosphere
Freon-12, 81 cm most probable depth) which provided differential energy
measurement in the range Eo = 20 - 65 GeV/n; and an eight-plane multiwire
proportional counter hodoscope which enabled particle trajectory
intersection points in the top layers of the emulsion chamber to be found
with rms position error 3.5 mm. A scintillation counter was placed below
the emulsion chamber to provide a measure of sh0wer-size from individual
energetic interactions within the chamber. (paper HEI.4-1 this conference)
A cross-plot of the outputs of the Teflon (CT) and lead-glass (CIG)
Cerenkov counters allowed separation of individual charge identification.
The ratio CT/CLG at Eo>2OGeV/n gives a narrow distribution for all particles
passing through both counters without interacting. This effect was used,
together with the hodoscope track information to reject most events
interacting in the electronic instrument. All detector signals were
corrected for path-length in the detector, PM tube temperature, detector non
uniformities, and ADC offsets. Charge resolution was limited by back-scatter
from the emulsion chamber, an effect which was assessed by correlation of CT
and CLG signals with the burst scintillator. Charge resolution was = 0.25
charge units FWHM at oxygen and 0.5 at Fe. Figure I shows a charge
histogram of a portion of the data. For the gas Cerenkov detector, in which
the PM tube outputs were analyzed in four sets of tubes, assessment and
correction for 6-ray effects in tube windows was possible. Energy
assignment for individual events was made using a Monte Carlo method which
incorporated the instrument response function and an assumed cosmic ray
spectrum. The response function was based on normal statistics of
photoelectrons from Cerenkov light plus a scintillation and BaSO 4 paint
Cerenkov contribution. The flight oxygen gas-Cerekov data is shown in Figure
. 3. It should be noted that energy assignments based on this method are
insensitive to changes in _ of 0.3 or so.
The balloon and instrument were launched on June 2nd from Greenville,
S.C. and cu_ down near Roswell, N.M., after 39 hours at a mean float depth
of 4._ gcm . Effective live time was 35.6 hrs. yielding an exposure of
5.7 m-sr hrs of the best quality data. The geometric aperture 0.16 m sr in
this case included all the electronic detectors except the burst-counter.
4.1-9 
 
The pri ary objective of this experi ent as to obtain a statistically 
i nificant s ple f y i  i t ractions i  t  ergy r e - 0 
eV/n, belo  the energy range of detection for t tally passive cha bers. 
ther jectives ere t  llo  ir ct li ration f so e t niques se  i  
J EE, l eit i  a lo er ergy r e th  t  t er periments. e 
electronic counters also allo ed the irect easurement of heavy pri ary 
s ic r  fl es i  t  r e - 00 e /J ( -  e  t t l r y f r e) 
r parison ith  t er EE irect pos tion easurements e 13 
 t t l ergy,  er OG4.1-13 t i  nference). I  t i  er e 
escribe  easurement   ndances  ectra  ents ro    
 ve  eV/n. 
xperimental 
The apparatus as previously described ( ef.l) and is only riefly 
i ed ere.  nsisted f  li  erenkov unters fl n  
d-glass) hich ere  t ration t  ergies orted ere  
r vided ri ary arge finition; a s erenkov unter (1 t osphere 
Freon-12, 81 c  ost probable depth) hich provided differential energy 
easurement i  t  ra e o = 20 - 65 eV/n; and a  i ht-plane ultiwire 
roportional unter doscope hich e abled article tr j tory 
i t rsection oints i  t  t  l ers f t  ulsion ber t   f  
ith r s position error 3.5 .  scintillation counter as placed belo  
t  ulsion c a ber t  r vide a easure f s ower-size fr  i ividual 
ergetic t ractions ithin t  a ber. per EI.4-l is nference) 
 r s-plot f t  tputs f t  eflon ( ) a  l d-glass ( l ) 
erenkov counters allo ed se aration of i ividual charge i entification. 
he r ti  /  t o>20GeV/n i es a arr  istribution f r ll articles 
passing through both counters ithout interacting. his effect as used, 
t ether ith the hodoscope trac  i f r ation to reject ost events 
i t racting i  t  l ctronic i tr ent. ll tector i als ere 
c rrected f r ath-length i  t e etector, P  tube te perature, etector non 
niformities, a  C ffsets. harge r s lution as li ited by ack-scatter 
~ om t  ulsion amber,  ff ct hich as sessed  relation f  
  nals ith  rst inti lator. harge solution as  .  
c arge nits F  t oxygen and .  t e. i ure 1 sho s a c arge 
ist ram f a ortion f t  ata. r t  s erenkov etector, i  hich 
the P  tube outputs ere analyzed i  four sets of t es, assess ent and 
correction for 6-ray effects in tube indows as possible. Energy 
assign ent f r i ividual e ents as ade using a onte arlo ethod hich 
i corporated t  i str ent r s onse f ction a d a  ass ed c s ic r  
ectrum. he s onse ction as sed  r al t tistics f 
photoelectrons from Cerenkov light plus a scintillation and BaS0  paint erenkov ntribution. he fli t ygen s- erekov ata i  s n i  i ure 
3. It should be noted t at energy assignments based on t is ethod are 
i sensitive t  anges i  r f .  r s . 
he all on and i str ent ere la ched  J e 2nd fr  r enville, 
S.C. and c~~ down near Roswell, N.M., after 39 hours at a mean float depth 
of 4.~ g cm. Effective live time was 35.6 hrs. yielding an expo~ure of 
.   sr rs f t  est uality ata. he ometric erture . 6  r i  
t is ase i l ded ll t  l ctronic etectors cept t e urst-counter. 
OG4.1-9
34
RESULTS
The derived differential energy spectra for the principal elements and
groups are shown in Figures 3 to 6, using data at the Instrument. Note that
the amplitudes given in these figures are per 5 GeV bin and for the whole
flight. Calculation of the differential and integral intensities at the
top of the atmosphere using average values of atmosphere and instrument
fragmentation show essential agreement with the HEAO C-2 data. Maximum
likelihood fits have been made to the raw spectra above 25 GeV/n and derived
values of 7 are given in the table (dN/dE = AE -7 ). Although
primary/secondary element ratios await the full interaction correction, an
estimate of the Fe/C+O ratio above 25 GeV/n is 5.4 X 10-2 if the ratio of
the interaction corrections for Fe and (C+O) is taken as 1.12. This
primary ratio has been reported as 6 X 10-2(Refs. 2,3).
References:
i. Austin, R.W., et.al., Papers of 18th ICRC T2-15, (1983)
2. French-Danlsh HEAO-3 Collaboration, Papers of
18th ICRC Vol 2, p 17 et. seq. (1983)
3. Simon, M. et.al., ApJ, 239, 712-724 (1980)
TABLE I
MAXIMUM LIKELIHOOD FITS TO ELEMENTAL SPECTRA ABOVE 25 GeV/n
ASSUMING SIMPLE POWER LAW, dN/clE = AE -?
A 7
Particles
(m2sr s GeV/n) -I
Oxygen 21.7 2.77 + 0.07 (-0.04)
Neon 4.2 2.72 + 0.13 (-0.12)
Magnesium 1.5 2.44 + 0.12 (-0.i0)
Silicon 5.8 2.85 + 0.15 (-0.i0)
16 z 25 1.4 2.89 + 0.18 (-0.I0)
Iron 0.51 2.79 + 0.25 (-0.19)
Sum of Z=8,10,12,14 5.8 2.72 + 0.05 (-0.06)
34 
RESULTS 
The derived diff rential energy spectra for the principal elements and 
groups are shown in Figures 3 to 6, using d ta at the instrument. Note that 
the amplitudes given in th se figures are per 5 GeV bin and for the whole 
flight. Ca culation of the diff rential and integral intensities at the 
top of the atmosphere using average values of atmosphere and instrument 
fragmentation show essential agre ment with the HEAD C-2 d ta. Maxi um 
likelihood fits have been made to the raw spectra above 25 GeV/n and derived 
values of ~ are given in the table (dN/dE = AE -~ ). Although 
primary/secondary element ratios await the full interaction correction, an 
estimate of the Fe/C+O ratio above 25 GeV/n is 5.4 X 10-2 , if the ratio of 
the interaction corrections for Fe and (C+O) is taken as 1.12. This 
primary ratio has been reported as 6 X 10-2(Refs. 2,3). 
References: 
1. Austin, R W., et.al., Papers of 18th ICRC 
2. French-Danish HEAO-3 Collaboration, Papers 
18th ICRC Vol 2, P 17 et. seq. (1983) 
3. Simon, M. et.a1., ApJ, 239, 712-724 (1980) 
TABLE 1 
T2-15, (I 983) 
of 
MAXI UM LIKELIHOOD FITS TO EL MENTAL SPECTRA ABOVE 25 GeV/n 
ASSUMING SIMPLE POWER LAW, dN/dE = AE-~ 
Oxygen 
Neon 
Magnesium 
Silicon 
16 z 25 
Iron 
Sum of 2=8,10 2,14 
A 
Particles 
(m2sr s GeV/n)-l 
21. 7 
4.2 
1.5 
5.8 
1.4 
0.51 
5.8 
2.77 + 0.07 (-0.04) 
2.72 + 0.l3 (-0.12) 
2.44 + 0.12 (-0.10) 
2.85 + 0.15 (-0.10) 
2.89 + 0.18 (-0.10) 
2.79 + 0.25 (-0.19) 
2.72 + 0.05 (-0.06) 
OG4.1-9 
35
80.00 Mg COMBINEDPULSEHEIGHT ' ' ' ' ' ' ' ' ' I ' ' ' ' .... ' I ' ' ' ' ' ' ' ' 'J
II DISTRIBUTION FROM SOLID
Ne II Si CERENKOVCOUNTERS • 80
l°.OO 2o._oo so,oo 4o.oo so.oo'- * - - _- _ _o.oo
_COMBINEDPULSEHEtGHT) t * * ,
Fig. i. Charge Histogram of Flight
Data; E o > 20 GeV/n Fig. 2. Histogram of Oxygen Data
in the Gas Cerenkov
I ' l I l • I I I 4m I I I I I I I
10 OX_ O+' I I I I I i ,
.=/
<
I ! I w I ! I w - J::: w I w w , ! w I
Z
w
"" SUB-IRON (16 <_ Z _ 25)
"- IRONloo
1°I
I I I ,,
20 50 80 20 50 80
ENERGY (GeV/N) ENERGY (GeV/N)
Figures 3-6. Differential Spectra of Individual Elements and Groups of
Elements Measured at the Instrument. Note that Amplitudes are per 5 GeV
bin and per Entire Flight, and Interaction Corrections have not yet been
applied. Straight Lines are M-L fits to the Data.
~ 
w 
> 
w 
80.00 ,..----'--------------, 
Mg 
, Si 
60.00 
COMBINED PULSE HEIGHT 
DISTRIBUTION FROM SOLID 
CERENKOV COUNTERS 
5 
80 
60 
~ 
a: 40.00 
w 
III 
~ 
Z 
~ 
... 
"-
.. 
~ 
J: 
z 
 
a: 
w 
"-
"-
is 
40 
F, 
20.00 
20 
o ~-~~--~~-~~ ~~~-~ 10.00 0.00 
ICOMBINED PULSE HEIGHT) 1 0 
Fig. 1. harge istogram of light 
ata; Eo > 20 GeV/n 
GAS CERENKOV (ARB. UNITS) 
Fig. 2. Histogram of Oxygen Data 
 e as erenkov 
100 
10 
-
O+NE+MG+SI 
OXYGEN t 
B-IRON  ~  ~ ) 
' N 
20 50 80 20 60 80 
RGY aVIN) RGY aVIN) 
Figures 3-6. ifferential Spectra of Individual Elements and roups of 
lements easured t t e strument. ote t at mplitudes re er   
bin and per Entire Flight, and Interaction Corrections have not yet been 
applied. traight ines are -L fits to the ata. 


Primary cosmic ray spectra in the range 20-60 GeV/n

Primary cosmic ray spectra in the range 20-60 GeV/n

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