Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft

Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft Summary and Issues of Workshop, Bad Liebenzell, Dec. 2003 Bianca Keilhauer Tokyo, February 26th, 2004

Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft Bianca Keilhauer Tokyo, February 26th, 2004 http://www.auger.de/events/air-light-03/ • 4 interesting days in December 2003 • 39 participants • 25 presentations • 10 projects • ⇒ improvements in understanding the aspects of molecular physics and in experimental measurements

Bianca Keilhauer Tokyo, February 26th, 2004 Fluorescence Light - starting theory - Franck-Condon-Principle for absorption and fluorescence A. N. Bunner: Cosmic Ray Detection by Atmospheric Fluorescence, PhD thesis 1967

M. Nagano Fluorescence from Nitrogen N2 N２＋ 1st Negative band 2nd Positive band Data from Bunner (1964) : weighted averages of three experiments with an accuracy of not better than ±30%. Kakimoto et al (1996) : 1.4MeV-1000MeV are mainly used in UHECR experiments.

M. Risse Energy Spectrum

R. Engel E. Marques Idea The „classic“ method of determination of Ne (X) is subject to a purely geometrical correction due to the lateral spread of shower particles. • conventional approach: Bianca Keilhauer Tokyo, February 26th, 2004 Discussion on Fluorescence Yield of an EAS

R. Engel E. Marques • ionization energy approach: Bianca Keilhauer Tokyo, February 26th, 2004 Discussion on Fluorescence Yield of an EAS

R. Engel Ionization energy deposit: problems • Assumption • No clear experimental evidence • Precision of energy reconstruction will depend on fluorescence yield data • Angular spread and definition of track length dX • Track length along shower axis • Actual track length of particles • Energy loss in fluorescence yield experiments • Low energy ( E≪ Ec): ionization loss • High energy: ionization and radiative losses (small cascades) • Detailed simulation of ionization energy deposit needed • Calorimetric energy Ecal not equal to total shower energy

P. Colin Dependencies Excitation Desexcitation Measured dependencies today :only E, P and λ Macfly project :PO2, PH2O, (T, nature)

M. Fraga Excitation processes • The C3Pu electronic state is a forbidden state; it cannot be directly excited by fast charged particles. H. Brunet, PhD thesis, UPS,Toulouse,1973 Elim (C3Pu) = 11.03 eV P.I. = 15.6 eV W ~ 36 eV Brunet PhD: http://www.auger.de/events/air-light-03/#phd_brunet

B. Keilhauer with and Fluorescence Light • EAS excites N2 molecules in air • 18 transitions in 2P system between 300 and 400 nm • 1 transition in 1N system between 300 and 400 nm • Calculation follows the principle way suggested by A. Bunner, 1967 ⇒ quantum efficiency of fluorescence =

B. Keilhauer Fluorescence Efficiency with p/p‘νfor air (79% N2 and 21% O2):

B. Keilhauer sum in the region 300 – 400 nm 337,1 nm ≙ ① 357,7 nm ≙② 391,4 nm ≙③ 29,2% fluorescence efficiency (photons/MeV) 23,3% @ 0 km: ①+②+③= 65,7% @ 20 km: ① +② + ③= 63,2% 10,7% 31,8% 25,3% 8,6% height (km) Fluorescence Efficiency Profiles

M. Fraga Electron impact cross sectionsfor N2 and O2 Qd el. exc-S ion ion vib vib att exc-T rot Dashed curves - excitations Magboltz -CERN Pitchford and Phelps, MagBoltz

Bianca Keilhauer Tokyo, February 26th, 2004 Arqueros, Madrid, < 30 keV Nagano, Fukui Univ. Waldenmaier, AirLight Gorodetzky, Paris Colin, MacFly 1. phase Fraga, LIP-Lisboa Kemp, Campinas 1. phase Privitera, AIRFLY, e±-beam at BTF, 50-750 MeV Colin, MacFly 2. ph., e±/μ-beam at CERN 25-100 GeV Reil, Flash, e--beam at SLAC 28 GeV Kemp, 2. ph., e--beam at LNLS1.37 GeV Ulrich, Munich, 12 keV 2. phase: medical acc. 5-12 MeV

F. Arqueros Nagano et al. Astroparticle Phys. (2003) Photon yields vs Bethe-Bloch FY seems to be proportional to dE/dx for E > 0.8 MeV. dE/dx grows fast at low energies. Does this relationship hold at very low energy?

F. Arqueros Preliminary set-up: the collision chamber F. Blanco and M. Ortiz HV (0  – 30 kV ) Nd:YAG vacuum pump photodiode/trigger collision chamber gas inlet PMT Digital Scope vacuum pump UV filter Faraday cup or scintillator Electron beam features • Energy up to 30 KeV. • Pulse Rate = 1 – 20 Hz • Time width = 20 ns (limited by the laser / plasma). • Intensity up to 200 mA peak. • Beam diameter 2 mm. Some stability problems !! • Differential pumping (up to 100 mtorr) • 1 PMT ORIEL 77348 (single counting) + UV filter • Digital scope (1 ns)

A. Ulrich Bianca Keilhauer Tokyo, February 26th, 2004 High-precision Measurements of Experts for „Particle beam induced light emission“ Energy deposition in the gas (1 bar Ar) Parameters for low energy electron beam excitation: Particle energy: typically 15 keV Foil: 300 nm silicon nitride Gas: typically 0.1 to 2 bar Beam current cw typ. 10 μA av. (0.15 W) or pulsed Modelled using the „Casino“ Program P. Drouin, A.R. Couture, R. Gauvin, P. Hovington, P. Horny, H. Demers, Univ. de Sherbrooke, Quebec, Canada (2002)

A. Ulrich Usage of the membranes: (principle) Diagnostics and gas system: Time resolved optical spectroscopy Grating monochromators (f=30cm, 0.03 nm resolution 1.order) Wavelength range ~30 nm to 700 nm Time resolution ~10ns beam pulses, ~1ns electronic res. Detectors VUV-PMT,VUV MCP and diode array Sensitivity measurements: two WI-17G Lamps (OSRAM) and D2 arc-lamps (Cathodeon) Gas pressure 0 to ~ 2 bar (foil: 10 bar) Gas mixing system with hot-metal gas purifiers (rare gases) Capacitive manometers (MKS Baratron)

A. Ulrich Assignment: III. Preliminary results from air Spectra: Overview, 1 bar, ~12 keV electron beam excitation High resolution spectrum: Preliminary result. Needs to checked!

M. Nagano 90Sr （28.8y） β 90Y （64.1h） β 2.28MeV 3.3MBq 90Zr Electron beam average 0.85MeV 0.02% 99.98% 1.75MeV

M. Nagano A and B of various bands ⇒ For details: N. Sakaki --- right after this presentation

T. Waldenmaier AirLight Experiment • Goals • precise measurement of the ... • pressure dependence • temperature dependence • effect of water vapor • effect of oxygen and argon Filters [nm]: 317, 340, 360, 380, 394, 430, M-UG6

S. Klepser Effective Transmission Curves → „Effective Transmission Curve“ for every Filter can be averaged. Interference Filters Theory Rel. Error using 0°-Transmission > 20 % Rel. Error using eff. Transmission < 7 % → CWL of filters should be 1-2 nm above the observed wavelength.

G. Lefeuvre Bench Diagram Source holder Gaz injection Source : 90Sr Fluorescence zone Focusing lens Spectrometer “integral” PMT (PMT #2) Spectrometer PMT (PMT #3) Plastic scintillator • PMT #1below measures the 90Sr spectrum generates gates • PMT #2integral EUSO configuration [300- 400 nm] wavelength • PMT #3in spectrometer 1nm bandwidth Probes (T, P) Scintillator PMT (PMT #1)

P. Colin Macfly specificities Event by event measurement: Low electron density like in air shower. • Study of new dependencies : • Composition and contaminant (Macfly 1) • Mainly : O2 Percentage and Humidity • Shower Age (Macfly 2) Key point: Real electromagnetic shower study Shower = Σ component electrons ??

M. Fraga Results : primary scintillation of N2 2nd pos. system P = 105 Pa; T = 296 K; Dl = 9 nm H. Brunet, PhD thesis, UPS, Toulouse, 1973; a (2.8 MeV)

M. Fraga Quenching by water vapor: 0-0 band intensity decreases with increasing concentration of water vapor. Atmospheric pressure was assumed. Plans for the future • Measurement of band intensities of the 2nd positive system as a function of pressure and temperature; • Study of the role of water vapor on the light yields and on the emission spectra. • Participation in the tests at CERN in the SPS beam facility - proposal submitted by the Annecy group (Ref:MacFly-MEMO-01 of 11/24/2003)

E. Kemp Chamber Configurations • Particle Beam e- • Radioactive Source

E. Kemp • Yi = NE / NP • NE : coincidence excesses • NP : particle detector counting • i : gas type Relative EfficiencyGas Filling: Dry Air → N2 YN2 YN2 / Yair= 5.1± 0.3 Kakimoto et al. , NIM 372A, 527 (1996) ~ 5.6 Yair

P. Privitera Beam monitoring with the calorimeter • The calorimeter is used for absolute and relative beam intensity measurement (<1000 e-/bunch) • Calorimeter counts single electrons • pedest. • 1 e- • Time*24 (s) • 2 e- • 3 e- • 4 e- • ADC counts

P. Privitera Energy dependence of fluorescence yield • UG6 filter • The scan was performed several times with consistent results. • Preliminary • Np.e.(fluor.) • ADCcal x E/442 • 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%

P. Colin CERN Beam simulation CERN-SPS-X5 : 50 GeV electron beam Macfly2 Macfly1 Electrons Positrons 100 e- of 50 GeV Only 1 e- of 50 GeV

K. Reil ⇒ For details: J.N. Matthews --- right after the coffee break

Forschungszentrum Karlsruhein der Helmholtz-Gemeinschaft Bianca Keilhauer Tokyo, February 26th, 2004 • Exchange of already existing theoretical knowledge • Exchange of practical solutions for experiment „everyday life“ • Fruitful discussion, even during night in the cellar • Setup of an exchange platform on internet currently under construction http://www.auger.de/events/air-light-03/

Forschungszentrum Karlsruhe in der Helmholtz-Gemeinschaft