Electron Observation : Past, Present and Future S.Torii : Waseda University (Japan) Rome PAMELA Workshop

Model Dependence of Nearby Source Effect Ec=∞ 、 ΔT=0 yr, Do=2x10 29 cm 2 /s at 1 TeV Do=5 x cm 2 /s Ec= 20 TeV Ec=20 TeV 、 ΔT= yr Kobayashi et al. ApJ 2003 We need a precise measurement at TeV energies to confirm the near-by sources for all of the models.

As a conclusion, we will wait for much more study by ATIC, PAMELA, FERMI-LAT, H.E.S.S. and a new experiment in space, AMS-02. Moreover, we need accurate measurements up to 10 TeV for detection of nearby sources and,naturally,very-high-statistics observation for Dark Matter search in sub-TeV region with a detector which has performance: The systematic errors including GF is less than a few %. The absolute energy resolution is less than 5 % ( ~ATIC). The exposure factor is as large as several 100 m 2 srday ( ~ FERMI-LAT). Possibly, the performance does not depend on energies. It should be a dedicated detector for electron observation in space. Calorimetric Electron Telescope (CALET) is proposed.

CALorimetric Electron Telescope Dark Matter Japanese Experiment Module (Kibo) International Space Station Cosmic Ray Sources SNR γ γ Pair Annihilation Pulsar AGN γ e P χχ e+e+ e-e- CALET A Dedicated Detector for Electron Observation in 1GeV – 10,000 GeV

International Collaboration Team Waseda University ： S. Torii, K.Kasahara, S.Ozawa, S.Udo, N. Hasebe, M.Hareyama, N.Yamashita, O.Okudara, S.Kodaira JAXA/ISAS ： J. Nishimura, T. Yamagami, Y. Saito H. Fuke, M.Takayanagi, H. Tomida, S. Ueno, K.Ebisawa Kanagawa University ： T. Tamura, N. Tateyama, K. Hibino, S.Okuno Aoyama Gakuin University ： A.Yoshida, T.Kobayashi, K.Yamaoka, T.Kotani Shibaura Institute of Technology ： K. Yoshida, A.Kubota, E.Kamioka ICRR, University of Tokyo ： Y.Shimizu, M.Takita, T.Yuda Yokohama National University ： Y.Katayose, M.Shibata Hirosaki University: S. Kuramata, M. Ichimura, T okyo Technology Inst.: T.Terasawa, Y. Ichisada National Inst. of Radiological Sciences : Y. Uchihori, H. Kitamura Rikkyo University: H. Murakami Kanagawa University of Human Services : Y.Komori Saitama University: K.Mizutani Shinshu University : K.Munekata Nihon University: A.Shiomi NASA/GSFC: J.W.Mitchell, A.J.Ericson, T.Hams, A. A.Moissev, J.F.Krizmanic, M.Sasaki Louisiana State University: M. L. Cherry, T. G. Guzik, J. P. Wefel Washington University in St Louis: W. R. Binns, M. H. Israel, H. S. Krawzczynski University of Denver: J.F.Ormes University of Siena and INFN: P.S.Marrocchesi, M.G.Bagliesi, G.Bigongiari, A.Caldaroe, M.Y.Kim, R.Cesshi, P.Maestro, V.Millucci, R.Zei University of Florence and INFN: O. Adriani, P. Papini, L. Bonechi, E.Vannuccini University of Pisa and INFN: C.Avanzini, T.Lotadze, A.Messineo, F.Morsani Purple Mountain Observatory: J. Chang, W. Gan, J. Yang Institute of High Energy Physics: Y.Ma, H.Wang,G.Chen

CALET Overview CALET Mission Concept  Observation:  Electrons in 1GeV - 20 TeV  Gamma-rays in 20 MeV - 10TeV + Gamma-ray Bursts in 7 keV - 20MeV  P-Fe in several 10GeV TeV  Launch: HTV: H-IIB Transfer Vehicle  Attach Point on the ISS: Exposed Facility of Japanese Experiment Module (JEM-EF)  Life Time: 3(min.) - 5 years  Mission Status Phase A for Launch around 2013 in Plan CALET Payload  High Energy Electron and Gamma- Ray Telescope Consisted of - Imaging Calorimeter - Total Absorption Calorimeter  Weight: 1500 kg  Geometrical Factor: ~0.7 m 2 sr  Power Consumption: 640 W  Data Rate: 300 kbps JEM/EF CALET

CALET launched by HTV CALET HTV ISS Approach to ISS Pickup of CALET H-IIA Transfer Vehicle （ HTV) Launching of H-II Rocket Separation from H-II Launching Procedure of CALET CALET

SIA IMC TASC SACS Schematic Structure of the CALET Payload GBM MDP VSC GBM: Gamma-Ray Burst Monitor VSC: Visual Sky Camera MDP: Mission Data Processor SACS:Scitillator Anti-Coincidence System SIA: Silicon Pixel Array IMC: Imaging Calorimeter TASC: Total Absorption Calorimeter

Details of Each Component IMC TASC SIA SACS(ACD) Silicon Pixel Array x 2 layers ( Pixel ~1cmx 1cm) Charge resolution: 0.1e for p, 0.35e for Fe Segmented Plastic Scintillators for Anti-Coincidence Co-PI: Pier S. Marrocchesi

Examples of Simulation Events

Purposes of Electron Observation Expected Electron Spectrum by the CALET Observation for 3 years (~ 1000 m 2 sr day) Cygnus Loop 20,000 years 2,500 ly Monogem 86,000 years 1,000 ly Vela 10,000 years 820 ly Chandra ROSAT Anisotropy W=10 48 erg/SN I(E)=I 0 E -α Ｎ =1/30yr D=D 0 (E/TeV) 0.3 Search for the signature of nearby HE electron sources (believed to be SNR) in the electron spectrum above ~ TeV Search for anisotropy in HE electron flux as an effect of the nearby sources. Precise measurement of electron spectrum above 10 GeV to define a model of accele- ration and propagation. Observation of electron spectrum in 1~10 GeV for study of solar modulation Possible Nearby Sources T< 10 5 years L< 1 kpc Nearby Pulsars or Dark Matter

IMC TASC > (C) (A) Geometry for Analysis Energy Resolution Geometrical Factor Angular Resolution CALET Performance by Simulation

F E = R E = Rejection Power for survival of 95 % 4 TeV ~ 10 5 ( ~1 % residual GeV ~ 4x 10 5 ( ~ 0. 1 %) 1.27 M events of protons 4 TeV Electron7.;8 TeV Proton A little effect on electron flux by uncertainties in simulation model Rejection Power against Background Protons

DetectorEnergy Region (GeV) Energy Resolution e/p selection power Key Instrument (Thickness of CAL) SΩT （ m ２ srday) PPB-BETS (+BETS) 10 GeV 4000 (> 10 GeV) IMC : (Lead: 9 X 0 ) ~0.42 ATIC1+2 (+ ATIC4) 10 - a few 1,000 <3% ( >100 GeV) ~10,000Thick Seg. CAL (BGO: 22 X 0 ) +C Targets 3.08 GeV 10 5 Magnet+IMC (W:16 X 0 ) ~1.4 (2 years) FERMI-LAT20-1, % ( GeV) (20-1,000GeV) Energy dep. GF & residual protons Tracker+ACD +Thin Seg. CAL (W:1.5X 0 +CsI:8.6X 0 ) (1 year) AMS*1-1,000 ～ 2.5 ％ ＠ 100 GeV 10 4 (x 10 2 by TRD ) Magnet+IMC +TRD+RICH (Lead: 17X o ) ~100(?) (1year) CALET*1-10,000~2% (>100 GeV) > 10 5 IMC+Thick Seg. CAL (W: 4Xo+BGOr or PWO :27 X o ) 800 (3 years) Electron(+Postron) Detector and Performance *) Future Project