BESS Introduction Detector BESS (BESS-TeVspectrometer) Experimetns Data analysis (1) (2) Results Summary

Measurements of Galactic and Atmospheric Cosmic-Ray Absolute Fluxes

BESS Introduction Detector BESS (BESS-TeVspectrometer) Experimetns Data analysis (1) (2) Results Summary

Introduction

90% 9% 100~10 6 GeV J. Cronin, T.K. Gaisser, and S.P. Swordy, Sci. Amer. v276, p44 (1997) Spectrometer 5 10% Energy (GeV) 10 4 Flux (m 2 sr s GeV) -1 10-28 0.1 0.1~100 GeV Spectrometer Calorimeter/ Emulsion 10 6 ~10 12 GeV 10 12

(90 ) Spectrometer E < ~100 GeV 2 Calorimeter/ Emulsion E > ~100 GeV Spectrometer Calorimeter Emulsion

(~ 2000 ) BESS-98, AMS ~5% 100 GeV 100 GeV~1 TeV Spectrometer Calorimeter Emulsion BESS-98 (Sanuki et al. 2000) AMS (Alcaraz et al. 2000)

@ 100 GeV~ 1 TeV Spectrometer Emulsion Spectrometer Calorimetar Emulsion Calorimeter ν (E > 10 GeV) Spectrometer

E < 50 GeV/n BESS AMS ~15 % high E > 1 TeV/n JACEE RUNJOB 2 low

Spectrometer r B Rigidity (R Pc/Ze) = 0.3 B r δ (~1 Tesla) (~1 m) R = 1 GV r = 3 m R = 1 TV r = 3,000 m (δ ~ 80 µm) MDR (Maximum Detectable Rigidity) Spectrometer R/R = 100 % Rigidity BESS-98 MDR = 200 GV MDR > 1 TV spectrometer BESS-TeV

Proton Helium up to 100 GeV > 500 GeV up to 50 GeV/n > 200 GeV/n BESS-TeV BESS-98

hadronic interaction model Up-going µ @SK E > 10 GeV E p > 100 GeV

µ µ spectrometer LEP (L3+C, CosmoALEPH) (BESS, CAPRICE)

Spectrometer 100 GeV 500 GeV 100 GeV ~ 1 TeV 0.5 500 GeV/c

BESS BESS-TeV MDR 200 GV 1 TV (Lynn Lake) 1 (2002. 8) (KEK, ) 1 (2002.10)

Detector

BESS JET/IDC Rigidity ( Pc/Ze) interaction event TOF β, de/dx BESS-98 (β) Rigidity(R) (Z) m=zer 1/ β 2-1 Solenoid

BESS-TeV BESS-98 BESS-TeV Solenoid N (~2 ) JET/IDC New JET/IDC N = 28 52 New FADC 500 ch 1000 ch σ (~1.3 ) New JET/IDC σ = 200 µm < 150 µm L (~2 ) ODC L = 0.8 m 1.6 m δp/p δp p 2 Nσ L~L 2 MDR 200 GV 1.4 TV ODC

BESS-TeV spectrometer TOF Magnet ODC JET/IDC

JET/IDC JET JET/IDC 45 JET 8 48 points max 86.3 mm IDC 2 45 mm CO 2 90 %+Ar10 % < 150 µm 86

Outer Drift Chamber (ODC) 2 Focusing wires Drift wires 4 CO 2 90 %+Ar 10 % 55 mm < 150 µm Focusing wire Sense wires

ODC photo

Scintillation fiber counters (SciFi) ODC calibration 4 Calibration 64 mm 1 1 mm 2 64 2 SciFi ODC 1 16ch multi-anode PMT Sense wires 55 mm ODC 1 cell ODC Drift wires Square-shaped Fibers 1mm

ODC/SciFi 2002 2 @KEK PS 2GeV/c p/π + Scifi calibration ODC SciFi hit residual 10 µm ODC 120 µm 0.5 mm

Experiments

BESS-02 Lynn Lake ( ) Aug. 7, 20:58 CST Ft. McMurray ( 600km) Aug. 8, 17:46 CST / 37km / 4.7 g/cm 2 ( ) Live Time 11h 16.5 hours Live time 11.3 hours

µ KEK ( ) 2002/10/1 10/6 (100 ) Tsukuba 2002/10 Lynn Lake 2002/8 (g/cm 2 ) ( o C) Date (Oct. 2002)

Data Analysis (1)

Rigidity Raw data ( ) Template Parameter Rigidity Template ( ) Parameter Raw data Rigidity

JET/IDC ODC ~50 Track Track Sense wire JET 4 SciFi SciFi ODC Sense wire

(BESS-98 ) Parameter 100 GV Rigidity Paramter Parameter

Parameter (BESS-98 ) FADC (BESS-98 ) µ

Garfield template x-t relation 200 µm grid sense wire drift time Voltage contour Drift isochrones

ODC JET IDC JET ODC JET/IDC ODC R.M.S=16 µm JET ODC (mm) < 20 µm R.M.S.

Event example ODC JET/IDC ODC

JET σ = 130 µm 150 µm JET 130 µm IDC 129 µm ODC 123 µm ( µ, P >10 GeV/c) MDR 1.4 TV MDR 1.4 TV BESS-98 1 MDR 200 GV

M.C. M.C. FADC

M.C. JET Track quality χ 2 σ 1/R

Data Analysis (2)

(N obs ) Trigger, Fiducual volume interaction event (Single track ) Particle ID B.G. (N BG ) p e, µ, π, d µ e, p Selection/trigger efficiency Live time proton flux µflux kinetic energy momentum

Trigger Unbiased trigger (T0-CD) TOF coincidence (T0 trigger) (Count Down) (1 khz) 1/10 TOF (30 Hz) 1/1 Aerogel trigger (AC) Aerogel Aerogel Cherenkov counter Efficiency 93% (R>10 GV) TOF proton T0-CD (E <10 GeV) + AC (E >10 GeV) µ T0-CD T0 1/10 T0-CD Efficiency 93% AC 5GV 20GV

Particle ID p de/dx z = 1 β µ β p µ

Background p p e,µ,π (E > 1 GeV, < 2%) p 1 GeV ratio d (E > 3 GeV, < 2%) Flux µ e (P > 0.5 GeV/c, < 1.5 %) (0.3% @1 GeV/c) p (P > 2.5 GeV/c,< 2 %) 2.5 GeV/c ratio µ µ

SΩ, T live SΩ ( ) M.C. T live (live time) 1MHz ε (efficiency) p µ ε rec Track reconstruction Data > 99 % (R<100 GV, w/o ODC) > 90 % (R>100 GV, w/ ODC) ε single Single track cut M.C. 80 % (R=100GV) > 99 % ε PID Particle ID Data > 97 % > 99 % ε trig Trigger (T0-CD) Beam > 99 % (R<10GV) > 99 % (AC) Data 94 % (R>10GV) ε acc Accidental events Data 0.01 % 0 %

(proton ) Flux (F TOI ) Flux (F TOA ) 5 g/cm 2 η (Air survival efficiency) M.C. 93 % R air ( ) Secondary/Primary ratio Papini et al. 10 GeV 2%

Proton flux M.C. ODC-JET alignment P -1 Alignment 20 µm P -1 = 0.2 (TeV/c) -1 M.C.

Proton 2.7 2.75 5% Alignment 500 GeV 10% µ 3.2 3.4 proton Alignment 500 GeV/c 20% Deconvolution

(proton) E < 100 GeV < 3 % E > 200 GeV dominant (> 5 %) ε single E < 200 GeV dominant (2 3%) ε trig 10 < E < 100 GeV dominant (3%) Alignment E > 300 GeV dominant (> 5%) / < 15 % E < 540 GeV

(µ) dominant P < 20 GeV/c 1 2 % P > 100 GeV/c > 5 % Alignment error P > 100 GeV/c dominant (> 5%) / < 15 % P < 400 GeV/c

Results

(Proton) 1 540 GeV 6 flux Flux 15% Energy F Stat. F Syst. 1 GeV 1.0 % 2.6 % 10 GeV 0.7 % 3.9 % 100 GeV 3.2 % 5.6 % 500 GeV 10. % 11. %

(µ) 0.57 400 GeV/c Flux (µ + +µ - flux) 17% Momenum F Stat. F Syst. 0.6 GeV/c 0.8 % 1.2 % 10 GeV/c 1.1 % 1.0 % 100 GeV/c 2.7 % 2.6 % 400 GeV/c 12. % 12. %

(proton) Solar modulation 30 GeV < E k < 500 GeV (E 0 =100 GeV, syst.+stat. error) Φ = (4.66 ± 0.09) 10-2 (m 2 sr s GeV) -1 γ = -2.715 ± 0.025 Stat. error Syst.+Stat.

(Spectrometer) Spectrometer 500 GeV BESS(1998), AMS-01(1998) Solar modulation E > 30 GeV ( 5%) CAPRICE(1998) 10 15 %

(Emulsion) E > 10 4 GeV Emulsion (RUNJOB ) BESS-TeV F = Φ (E k /100 GeV) γ Φ = (4.66 ± 0.09) 10-2 γ = 2.715 ± 0.025 RUNJOB

ATIC Balloon-borne calorimeter Si Matrix Carbon target (~0.75λ 0 ) BGO calorimeter (~20X 0, ~1λ 0 ) Mean deposited energy: 36% Energy resolution: ~ 40 % (@1 TeV) 2000 Flight @ Antarctica Successful 16-days flight Preliminary result reported at ICRC 2003

(Calorimeter) ATIC Calorimeter, 2000 Preliminary result ICRC (2003.8 Tsukuba) (BESS-TeV ) BESS-TeV BESS-TeV ATIC (Preliminary, )

(µ) 0.6 400 GeV/c P < 100 GeV/c BESS, CAPRICE (5% ) BESS-95 0.6-30 GeV/c @KEK BESS-99 0.6-100 GeV/c @ (2770m) 30 GeV/c

BESS (Cosmo-LEP) P > 100 GeV/c LEP (10% ) L3+C

BESS-TeV spectrometer BESS MDR 200 GV 1.4 TV p, µ 2002 p 1 540 GeV 15 % spectrometer Φ = (4.66 ± 0.09) 10-2 (m 2 sr s GeV) -1 γ = -2.715 ± 0.025 (E 0 =100 GeV) µ 0.6 400 GeV/c 17 %