22 July 2004, Leeds New measurement on photon yields from air and the application to the energy estimation of primary cosmic rays Motohiko Nagano Fukui University of Technology

Collaboration with K.Kobayakawa, N.Sakaki and K.Ando

3 rd International Workshop on Ultrahigh-energy Cosmic Rays (2004) in honor of Alan Watson European Symposium at Leeds in 1970

Haverah Park in 1970

Raidio observation Central station Recording system Water tank Symposium

Workshops on Air Fluorescence

FIWAF 02

at Salt Lake City, October 2002 at Bad Liebenzell, Dec. 2003 Details are in http://www.auger.de/events/air-light-03

Summary of Experiments by Bianca Keilhauer

E kin (MeV) < 0.1

0.1 - 1 1 -10 Contr. (%) source experiment e 10 - gun 12 e from 90 Sr 23

Arqueros

,

Nagano

, Fukui Univ.

Madrid, < 30 keV

Waldenmaier

, AirLight

Gorodetzky

, Paris

Ulrich

, Munich, 12 keV

Colin Fraga

, MacFly 1. phase , LIP-Lisboa 10 - 100

Privitera

e ± 35

Kemp

, Campinas 1. phase 2. phase: medical acc. 5-12 MeV 100 -1000 17 > 1000 beam from accelerator , AIRFLY, beam at BTF, 50-750 MeV 3

Colin

, MacFly 2. ph., e ± / μ beam at CERN 25-100 GeV

Reil

, Flash, e beam at SLAC 28 GeV

Kemp

e , 2. ph., -beam at 1.37 GeV LNLS

In M.Nagano, K.Kobayakawa, N.Sakaki and K.Ando ; Astroparticle Physics, 20 (2003) 293-309

 Fluorescence yields were measured with 6 narrow band filters.

 Yields in unmeasured bands were estimated by multiply the yields given in Bunner, taking into account the average ratio of our measured values to the corresponding values listed in Bunner.

Filter

337.7nm

A photon counting and thin target technique is used.

Electron beam

90 Sr （ 28.8y

） β

99.98%

β 2.28MeV

3.3MBq

90 Y （ 64.1h

）

0.02% 1.75MeV

90 Zr

average 0.85MeV

Systematic errors

Item Quantum efficiency of PMT Collection efficiency of PMT Transmission coefficient of filter Contamination from lines at the tail of filter transmission Other parameters (I, a, Ω,η) Total Errors 5 % 10 % 5 % 4 % 4 % 13.5 % Statistical error in each run is less than 3%.

Equation of state of a gas, p=ρRT , where R is specific gas constant.

Photon yields per m

Y i



dE dx

   

h i

( 

p

)

i

 

dE dx

 : Energy loss (g cm -2 ) : Density 1 

i

(

p

)  1 

i

0   1 

p p

'  

h



i

: Photon energy 

i

0 : Fluorescence efficiency in the absence of collisional quenching (Fluorescence efficiency is defined by the radiated energy divided by the energy loss of the electron in a unit length) 1 1 

p p

' : fraction of available energy kept after collisional losses

p’

is the reference pressure

from Bunner

Nitrogen

Red curves are Y i after subtraction of other bands in the filter.

Air

Mixtures of N 2 : 78.8 % O 2 : 21.2 %

Photon yields between 300 and 406nm at 1 atmospheric pressure

12 keV

Average of three experiments

Comparison of fluorescence efficiencies 1 

i

(

p

)  1  0

i

  1 

p p

'   Present (0.85 MeV) Davidson and O ’ Neil(50 keV) Mitchell(8 keV) Kakimoto et al.(1.4 MeV)

Measurements between 300 and 1000MeV Kakimoto et al. NIM A372 (1995) 244.

Electrons from the electron synchrotron of the INS, University of Tokyo.

Energy dependence of photon yields

Air of 1 atm. pressure O : Kakimoto et al. cited from Ueno dE/dx curves are adjusted at 1.2 MeV

Energy dependence of fluorescence yield AirLight03, Bad Liebenzell, Dec. 2003

P. Privitera UG6 filter

N p.e.

(fluor.)

Preliminary The scan was performed several times with consistent results.

ADC cal x E/442 AIRFLY

Limited by multiple scattering on 1.5 mm thick exit Al window. The scan went down to 50 MeV.

Positrons (493 MeV) gave same yield within 3%

Photon yields as a function of density and temperature

Y i



where

d

E

d

x

d

E

d

x E

0 .

85 MeV 1 

A i



B i



T A i

 d

E

d

x

0 .

85

h



i

MeV

E i

0

B i



R air p

' 20 293 reference pressure at 20 o C

V.Rizi, Airlight03 at Bad Liebenzell, 2003

COSPAR International Reference Atmosphere CIRA1986 and US standard atmosphere altitude (km) 30 25 CIRA 1986 monthly mean profiles 20 15 10 US standard atmosphere winter summer 5 0 200 220 240 260 temperature (K) 280 300 0 4 variab. % 8

Altitude dependence of photon yields per meter per electron of 0.85 MeV

US Standard Atmosphere 1976 US Standard Atmosphere 1966

Photon yields in damp air

Nagano et al.

UHECR Conference at Annecy, 2001

Vapour pressure 9.5 hPa 13.4 hPa

Photon yields between 300 and 406nm 3 .

81 3 .

03  1 .

26 3 .

81 3 .

23  1 .

18

Photon attenuation with distance

Raileigh scattering only important at far distance

Energy Estimation

C. Song et al., Astroparticle Phys. 14(2000)7 Electromagnetic shower: mean Ionization loss rate:

E em



E c X

0 0  

N e

(

x

)

dx

  2 .

19

g

MeV

cm

2 CR calorimetric energy: Missing Energy:

E cal E

0

E cal

  0  

N ch

(

x

)

dx

 0 .

959  0 .

082  

E cal

0 .

150 ( m,, …)

Application of the photon yields to the energy estimation of UHECR

B.Dawson, GAP-2002-067(2002) fraction of the flux L(x) in bin i 

E dep

(

x

) 

x

 1 

x



i

 

L i

(

x

)(

h

 )

i



i

(

x

)

E cal

 1 

i

(

p

)  0   

E dep

(

x

) 

x

d

x

1 

i

0   1 

p p i

'    

p

 

R air T

at depth

x

M.Risse and D.Hech, Astroparticle Physics 20(2004) 661

        Assumptions:

By N. Sakaki CORSIKA 6.020 with QGSJET (2004) 661

（

M.Risse and D.Heck, Astropart. Phys. 20 proton, E=10 19 eV and 10 20 eV, θ=0 o , 60 o Emitted photons from dE/dx(g/cm 2 ) The observation height is 0 m a.s.l. Transmission by Rayleigh scattering (X R =2974 g/cm 2 )

T R

 exp    

x

1 

X R x

2 400    4   

Transmission by Mie scattering (scale height H M =1.2 km, horizontal attenuation length L M =25 km)

T M

 exp

L M H M

cos     exp   

US standard atmosphere 1976

h

1

H M

   exp   

h

2

H M

     400 [nm] 

Wave length dependence of HiRes filter transmission and quantum efficiency of Hires PMT are included

by N.Sakaki

Comparison of observed total photon number in various conditions

Energy spectrum of world data

Conclusions

    

From the pressure dependences of photon yields, fluorescence efficiencies for 15 bands in the absence of collisional quenching are determined.

Photon yields are determined as a function of the gas density and the temperature for 15 bands.

Total photon yields between 300nm - 406 nm are 26% larger than the summary by Bunner at 1013 hPa and at 20 o C.

Those are 18% larger than those used by the HiRes group. In estimating the primary energy of cosmic rays, it would be more realistic to estimate the energy deposit for each angular bin from the observed photons using the pressure dependence of fluorescence efficiencies of each band, whose values are determined and available now. M.Nagano et al. astroph-0406474