1. March 3, 2010HEAD2010 1 The Future Prospects for Electron Measurements, the Frontier above 1 TeV Shoji Torii Waseda University

2. March 3, 2010 HEAD2010 2 Electron & Positron Observation Evolution of the Universe Dark Matter Origin ( ⅰ ) Monoenergetic: Direct Production of e+e- pair （ⅱ） Uniform ： Production via Intermediate Particles （ⅲ） Double Peak ： Production by Dipole Distribution via Intermediate Particles Production Spectrum ⇒ MχMχ Annihilation of Dark Matter （ WIMP) χχ→e +,e - Production Spectrum （ Power Law Distribution ＋ Cutoff ） Shock Wave Acceleration in SNR Acceleration in PWN Astrophysical Origin ⇒ dN/dE  E -2 exp(-E/E c ) Log(E) Log(dN/dE) EcEc ↑ Propagation in the Galaxy Diffusion Process Energy Loss dE/dt =-bE 2 （ Syncrotron ＋ Inverse Compton ） ⇒ ⇒  +/- or K+/-   +/-  e+/- e + +e -

3. March 3, 2010 HEAD2010 3 e ± Propagation For a single burst with Atoyan 95, Shen 70 Kobayashi 03 Power law spectrum Diffusion Energy loss by IC & synchro. Injection ← B/C ratio

4. (F 0 : E 3 x Flux at 3TeV) March 3, 2010HEAD20104 A Naïve Result from Propagation T (age) = 2.5 X 10 5 X (1 TeV/E) yr R (distance) = 600 X (1 TeV/E) 1/2 pc 1 TeV Electron Source: Age < a few10 5 years very young comparing to ~10 7 year at low energies Distance < 1 kpc nearby source Source (SNR) Candidates : Vela Cygnus Loop Monogem Unobserved Sources? 1 TeV Electron Source: Age < a few10 5 years very young comparing to ~10 7 year at low energies Distance < 1 kpc nearby source Source (SNR) Candidates : Vela Cygnus Loop Monogem Unobserved Sources? GALPROP/Credit S.Swordy 1 GeV Electrons 100 TeV Electrons

5. March 3, 2010 HEAD2010 5 Model Dependence of Energy Spectrum and Nearby Source Effect Ec=∞ 、 ΔT=0 yr, Do=2x10 29 cm 2 /s Do=5 x 10 29 cm 2 /s Ec= 20 TeV Ec=20 TeV 、 ΔT=1-10 4 yr Kobayashi et al. ApJ (2004)

6. March 3, 2010 HEAD2010 6 We are waiting for much more study by ATIC, PAMELA, Fermi-LAT, HESS and a forthcoming experiment in space, AMS-02. Moreover, We need an accurate and very-high-statistics observation for searching Dark Matter and/or Nearby Pulsars in the sub-TeV to the trans-TeV region with a detector which has following performance: The systematic errors including GF is less than a few %. The absolute energy resolution is as small as a few % ( ~ATIC). The exposure factor is as large as more than 100 m 2 srday ( ~ FERMI-LAT). The proton rejection power is comparable to 10 5, and does not depend largely on energies. It should be a dedicated detector for electron observation in space. Calorimetric Electron Telescope (CALET) is proposed. Efforts by the new experiments for deriving the positron and electron spectra are really appreciated to open a door to new era in astroparticle physics.

7. March 3, 2010 HEAD2010 7 CALET Overview  Observation:  Electrons : 1-10,000 GeV  Gamma-rays : 10-10,000 GeV (GRB >100MeV) + Gamma-ray Bursts : 7 keV-20 MeV  Protons, Heavy Nuclei: several 10 GeV- 1000 TeV ( per particle)  Solar Particles and Modulated Particles in Solar System: 1-10 GeV (Electrons)  Instrument: High Energy Electron and Gamma- Ray Telescope Consisted of : - Imaging Calorimeter (Particle ID, Direction) Total Thickness of Tungsten (W) ： 3 X 0 Layer Number of Scifi Belts ： 8 Layers ×2(X,Y) - Total Absorption Calorimeter (Energy Measurement, Particle ID) PWO 20mm ｘ 20mm ｘ 320mm Total Depth of PWO ： 27 X 0 (24cm) - Silicon Pixel Array (Charge Measurement up in Z=1-35) Silicon Pixel 11.25mmx11.25mmx0.5mm 2 Layers with a coverage of 540x540 cm 2

8. March 2, 2010 HEAD2010 8 CALET Performance for Electron Observation SIA IMC TASC Electron 100 GeV Electron 1 TeV Geometrical Factor (Blue Mark) Detection Efficiency Energy Resolution ~2% See Poster for details ( Akaike et al.)

9. March 3, 2010 HEAD2010 9 The CALET mission instrument can satisfy the requirements as a standard payload in size, weight, power, telemetry etc. for launching by HTV and observation at JEM/EF. CALET System Design ＃９ Calorimeter Gamma-ray Burst MonitorStar Tracker Mission Data Controller Field of View (45 degrees from the zenith) JEM/EF & the CALET Port CALET Payload Weight : 483.5 kg Power Consumption: 313W

10. March 3, 2010 HEAD2010 10 CALET HTV ISS Approach to ISS Pickup of CALET H2-B Transfer Vehicle （ HTV) Launching of H-IIB Rocket Separation from H2-B Launching Procedure of CALET CALET

11. March 2, 2010 HEAD2010 11 Electron Observation (5 years) Vela Expected Anisotropy from Vela SNR Expected Flux > 1000 827 644 ~10% @1TeV Monogem Cygnus Loop

12. 12 Proton and Nucleus Observation （ 5years) O Mg Ne FeSi C CREAM 2ry/ 1ry ratio ( B/C)  Energy dependence of diffusion constant: D ~ E δ  Observation free from the atmospheric effect up to several TeV/n Nearby Source Model (Sakar et al.) Leaky Box Model

13. March 3, 2010 HEAD2010 13 Comparison of Detector Performance for Electrons Detector Energy Range (GeV) Energy Resolution e/p Selection Power Key Instrument (Thickness of CAL) SΩT （ m２srday) （ m ２ srday) PPB-BETS(+BETS) 10 -1000 13% @100 GeV 4000 (> 10 GeV) IMC : (Lead: 9 X 0 ) ~0.42 ATIC1+2 (+ ATIC4) 10 - a few 1000 <3% ( >100 GeV) ( >100 GeV)~10,000 Thick Seg. CAL (BGO: 22 X 0 ) + C Targets 3.08 PAMELA1-7005% @200 GeV 10 5 Magnet+IMC (W:16 X 0 ) ~1.4 (2 years) FERMI-LAT20-1,000 5-20 % (20-1000 GeV) 10 3 -10 4 (20-1000GeV) Energy dep. GF Tracker+ACD + Thin Seg. CAL (W:1.5X 0 +CsI:8.6X 0 ) 300@TeV (1 year) AMS1-1,000 (Due to Magnet) ～ 2.5 ％ ＠ 100 GeV 10 4 (x 10 2 by TRD ) Magnet+IMC+TRD+RICH (Lead: 17X o ) ~100(?)(1year) CALET1-10,000~2% (>100 GeV) ～ 10 5 IMC+Thick Seg. CAL (W: 3 X o + PWO : 27 X o ) 220 (5 years) CALET is optimized for the electron observation in the tran-TeV region, and the performance is best also in 10-1000 GeV.

14. March 3, 2010 HEAD2010 14 A New Technology and Space Experiments after CALET The Cosmic Ray Electron Synchrotron Telescope (CREST) (ICRC 2009, S.Nutter et al.) CREST payload for Ballooning: 40 days at 4 g/cm 2 in Antarctica Challenging New Technology: Synchrotron X rays from electron Expected electron detection efficiency  Very large acceptance: Vela detection up to 10 TeV (~ a few TeV for HESS )  High Threshold: E> 2 TeV  Poor energy resolution : ~ a factor of two 32x32 BaF 2 Crystals (40% coverage) 2.4 m E x > 30 keV TANSUO (J.Chang et al.) HEPCaT as part of OASIS (J.W. Mitchell et al.) Hodoscope + BGO Calorimeter SΩ~0.4 m 2 sr SΩ~2.5 m 2 sr Sampling Silicon-W Calorimeter + Secondary Neutron Detector

15. March 3, 2010 HEAD2010 15 The electron measurement over 1 TeV can bring us very important information of the origin and propagation of cosmic- rays and also of the dark matter ( yet not discussed here). We have successfully been developing the CALET instrument for Japanese Experiment Module (Kibo) – Exposed Facility to extend the electron observation to the tans-TeV region. The CALET has capabilities to observe the electrons up to 10 TeV, gamma-rays in 10GeV- 10TeV, proton and heavy ions in several 10 GeV - 1000 TeV, for investigation of high energy phenomena in the Universe. The CALET mission has been approved by the System Definition Review (SDR), and will proceed to the Phase B soon for launching in 2013. Summary and Future Prospect

16. March 3, 2010 HEAD2010 16 International Collaboration Team Waseda University: S. Torii, K.Kasahara, S.Ozawa, H.Murakami, Y.Akaike, T.Suzuki, R.Nakamura, K.Miyamoto, T.Aiba, M.Nakai, Y.Ueyama, N. Hasebe, J.Kataoka JAXA/ISAS: M.Takayanagi, H. Tomida, S. Ueno, J. Nishimura, Y. Saito H. Fuke, K.Ebisawa, M.Hareyama Kanagawa University: T. Tamura, N. Tateyama, K. Hibino, S.Okuno, T.Yuda 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 Yokohama National University: Y.Katayose, M.Shibata Hirosaki University: S. Kuramata, M. Ichimura Tokyo Technology Inst.: T.Terasawa, Y. Tunesada National Inst. of Radiological Sciences: Y. Uchihori, H. Kitamura KEK: K.Ioka, N.Kawanaka Kanagawa University of Human Services: Y.Komori Saitama University: K.Mizutani Shinshu University: K.Munekata Nihon University: A.Shiomi Ritsumeikan University: M.Mori 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: K. Batkov, M.G.Bagliesi, G.Bigongiari, A.Caldaroe, R.Cesshi, M.Y.Kim, P.Maestro, P.S.Marrocchesi, V.Millucci, R.Zei University of Florence and INFN: O. Adriani, L. Bonechi, P. Papini, 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

17. March 2, 2010 HEAD2010 17 CALET The CALET Mission to Search for Nearby Cosmic-Ray Sources and for Dark Matter Shoji Torii e-mail: torii.shoji@waseda.jp Waseda University CALET

18. March 3, 2010 HEAD2010 18 BACKUP

19. March 2, 2010 HEAD2010 19 Cosmic-ray electrons Cosmic-ray protons  Flux of electrons and positrons: ~1 % of protons @10GeV ~0.1 % @ 1000GeV ~0.1 % @ 10 GeV  Spectrum of electrons: softer than protons power-law index: e:~-3.0, p:-2.7 => As higher energies, Lower electron flux Lager proton backgrounds Large amount of exposures with a detector of high proton rejection power (+ charge separation) Long duration balloon flight in 10~1000 GeV (~10 m 2 srday) Observation in space for years over 1000 GeV (> 100 m 2 srday) Cosmic-ray Energy Spectra a few electrons / m 2 sr day a few electrons / cm 2 sr day Electron and Positron Observation

20. March 2, 2010 HEAD2010 20 Astrophysical Source Candidates Supernova Remnants –Shock Acceleration gives a d  /dt  E -2 exp(-E/E c ) spectrum injected into the ISM, where E c ~ 10 TeV. Pulsar Wind Nebulae (PWNe) –Highly magnetized, fast spinning neutron stars. –Gamma-rays and electron/positron pairs produced along the magnetic axis –The pairs are accelerated at the PWN termination shock, again giving a d  /dt  E -2 exp(E/E c ) injection Microquasars –Relativistic jets sending out beams of mono-energetic electrons into the ISM Interactions of CR nuclei with interstellar gas – producing  +/- or K+/-   +/-  e+/-

21. March 2, 2010 HEAD2010 21 New Calculation for SNR Origin S.Profumo arXiv:0812.4457v2 28 Apr. 2009 Electron + Positron Positron Ratio Source Candidates

22. March 2, 2010 HEAD2010 22 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 CALET

23. March 2, 2010 HEAD2010 23 Launch of the H-IIB Launch Vehicle Test Flight  Launched on Sep.11, 2009 at Yoshinobu Launch Complex at the Tanegashima Space Center in Japan  Docked successfully to ISS on Sep. 18, 2009. c JAXA

24. March 2, 2010 HEAD2010 24 MAXI SMILES SEDA Payloads on Japanese Experiment Module (Kibo) /Exposure Facility at Present c JAXA

25. March 2, 2010 HEAD2010 25 MAXI SMILES SEDA-AP 衛星間通信システム 実験ポート HREP MCE CALET Future Plan of JEM/EF (~2013)

26. March 2, 2010 HEAD2010 26 Electron Observation (5 years) – Astrophysical Model- KK DM(Δt=0) vs SNR type (Δt=10 5 year) ----- KK DM SNR Type SNR Type vs Pulsar (Δt=3×10 5 year) ----- Pulsar Type SNR Type CALET ObservationCALET Observatuib age=5.6x10 5 yr, E e =1.7x10 50 erg, spectral index=1.7 Source SNR Type （ exp(-t) ） Pulsar Type （ｔ -2 )

27. March 2, 2010 HEAD2010 27 Dark Matter Search Efficiency Expected electron + positron excess by KK dark matter (Mass 620 GeV) by the CALET observation 2 years （ BF=40) or 5 years （ BF=16) 2 years （ BF=5) or 5 years （ BF=2) Expected gamma-ray excess by SUSY DM ( Mass = 820GeV) by the CALET observation

28. March 2, 2010 HEAD2010 28 AMS (stars) HEAT (triangles) BETS (circles) PPB-BETS (crosses) Emulsions (diamonds) ATIC (red circles) Observed (e + +e - )Spectra (as of 2008) & e + /(e + +e - ) Ratio If we assume the power law spectrum ( with γ=-3.3) calculated by GALPROP, an excess of (e + +e - ) is seen in 300-800 GeV. The excess might be contributed from exotic sources: Nearby Pulsars or WIMPs. J. Chang et al. Nature (2008) Nature MLP+BDTD (+data, no pre-sampler, improved knowledge of detectors) GALPROP PAMELA e + /(e + +e - ) Ratio (RICAP, 2009) statistics improved by ~2.5 ÷ 3 The positron ratio observed by PAMELA presents unexpected increase over 10 GeV. This increase can be understood if the positrons are created by Nearby Pulsars or WIMPs in addition to secondary process. Both anomalies from same reason ? To identify the reason, Anisotropy in (e + +e - ) and e + /(e + +e - ) over 100 GeV are indispensable. Both anomalies from same reason ? To identify the reason, Anisotropy in (e + +e - ) and e + /(e + +e - ) over 100 GeV are indispensable.

29. March 2, 2010 HEAD2010 29 Then, excellent observations of (e + +e - ) in statistics are carried out by FERMI-LAT and HESS, and a new era of electron observation is opened probably by indicating a flattening of energy spectrum and a sharp cut-off over 1 TeV, respectively. I really appreciate their efforts to derive the electron spectrum in unexploded region. F.Aharanian et al. arXiv:0905:0105

30. March 2, 2010 HEAD2010 30 Gamma-ray CALET Performance for Electron Observation (2) Angular Resolution Electron SΩ ( for electrons) vs Incident Angle Integral Differential See Blue Marks

31. March 2, 2010 HEAD2010 31 Why we need CALET ? Residual hadron contamination FERMI Electron Analysis Geometric Factor depends strongly on energy Proton rejection power depends fully on simulation by using different parameters Energy resolution becomes worse at high energies (~30 %@ 1 TeV) Expected CALET Performance Geometric Factor is constant up to 10 TeV Energy resolution is nearly 2 %, and constant over 100 GeV 10 4 1.6 M protons Proton rejection power at 4 TeV is better than 10 5 with 95 % electron retained Blue Mark CALET is a dedicated detector for electrons and has a superior performance in the trans-TeV region as well as at the lower energies

32. March 2, 2010 HEAD2010 32 Validation of the flight data Task: Task: compare the efficiency of all “cuts” for flight data and MC eventsApproach: - Plot from the flight data the histogram of each variable involved in the electron selections, one at a time, after applying all other cuts - check if the flight histograms match the simulated ones, and account for the differences in systematic errors for the reconstructed spectrum Example for the variable (shower transverse size) Analysis variables demonstrate good agreement between the flight data and MC

33. March 2, 2010 HEAD2010 33 F.Aharanian et al. arXiv:0905:0105 PRL,201, 261104 (2008) The H.E.S.S. analysis depends on simulation, and the residual protons are as dominant as similar with an amount of the electrons, or more at lower energies.

34. March 2, 2010 HEAD2010 34 Calorimeter Thickness: 17 X 0 => Energy Leakage over 50 GeV NIM 490 (2002) 132