Outline of CALET presentation at SciNeGHE conference

Nicola Mori INFN Florence & University of Florence

CALET M&S meeting – GSFC – 23 May 2012 The conference

● “Science with the New Generation of High Energy Gamma-ray Experiments”

● 20-22 June 2012, Lecce (Italy)

● From conference website: “The 2012 edition of the SciNeGHE conference will focus on the interplay between studies and measurements concerning high energy gamma ray sources and cosmic rays.”

● http://scineghe2012.le.infn.it/

Plan of the presentation

● Introduction to CALET – The collaboration – The instrument – General performance (energy resolution etc.) ● Expected results – Electrons and positrons – Nuclei – Gamma ● Electron/proton discrimination Italy Participating institutions • University of Siena • University of Florence & IFAC (CNR) • University of Roma Tor Vergata • University of Padova

CALET is a CERN Recognized Experiment

Japan

● Waseda University ● Yokohama National University ● United States JAXA/Space Environment ● Hirosaki University ● NASA/Goddard Space Flight Center Utilization Center ● Tokyo Technology Inst. ● ● Louisiana State University JAXA/ Institute of Aerospace ● National Inst. of Radiological Sciences ● Washington University in St. Louis and Astronautical Sciences ● High Energy Accelerator Research ● ● University of Denver Kanagawa University, Organization (KEK) ● Aoyama Gakuin University ● Kanagawa University of Human Services ● Shibaura Institute of Technology ● Saitama University ● Institute for Cosmic Ray Research, ● Shinshu University University of Tokyo ● Nihon University ● Ritsumeikan University Payload overview

C

Instrument overview

z

y CHD (CHarge Detector)

● 14 pads per view, EJ204 plastic scintillator (polyvyniltoluene, PVT)

2 Bethe-Bloch formula dE/dx ∝ Z (relativistic)

Minimum ionizing CHD discriminates particle (MIP) between different |Z| Z=2 ● Electron/proton separation will require a different approach Z=1

W layers IMC (IMaging Calorimeter) PS fiber layers

● 8 layers, 448 polystyrene fibers (1mm section) per view ● W layers above PS fibers (except for 1st layer), variable height

● Total depth ~ 3 X0, ~ 0.1 λ

Fiber readout: Hamamatsu H7546B multianode PMT (64 channels) IMC provides particle's track and finely-segmented information about initial development of EM showers

TASC (Total AbSorption Calorimeter)

● 12 layers, 16 lead tungstate (PWO) logs (2 cm section) per view ● Homogeneous calorimeter

● Total depth ~ 27 X0, ~ 1.2 λ ● Energy resolution for e± above 100 GeV: ~ 2 %

Readout: APD + PD, Hi and Low gain shapers for each → 4 regimes → high dynamic range (0.5 → 107 MIP) TASC provides energy measurement in a wide range and informations about shower development

Performances and scientific goals

● Sensitivity: ● Electrons: 1 GeV – 20 TeV ● Hadrons (H → Fe): ~ 10 GeV – 1000 TeV ● Gamma rays: 10 GeV – 10 TeV

● TASC energy resolution: ● Electrons and gamma rays: ~ 2% @ E > 100 GeV ● Protons: ~ 40% @ 1 TeV ● Nuclei: ~ 30% @ 50 GeV/n (12C and 56Fe)

● CHD charge resolution: 15% - 30% (2 ≤ Z ≤ 26)

● e/p rejection power: ~ 105

● Acceptance: 0.12 m2 sr

● Planned duration: 5 years

From test beam @ GSI Electrons from nearby SNR sources

(Kobayashi et al. 2004)

Dark matter search: electrons+positrons

(e++e-) spectrum from Kaluza-Klein Dark Matter annihilation

2yr (BF=40) or 5yr (BF=16)

e++e- flux from fermionic DM decay: + - ΨDM →l l ν

MDM = 2.5 TeV (solid line) 26 (Ibarra&Tran 2010) ΤDM = 1.5x10 s

Dark matter search: gamma rays

: EGRET (Sreekumar et al. 1998) ■: EGRET (Strong et al. 2004)

DM contribution

(Ibarra, Tran & Weniger 2010) Diffuse gamma-ray flux from fermionic DM decay: + - ΨDM →l l ν

MDM = 2.5 TeV (solid line)

26 ΤDM = 1.5x10 s Protons and helium

Heavier nuclei

B/C ratio

CALET at work

100 GeV electron 100 GeV proton

Geant4 simulations 100 GeV gama ray 50 GeV/n 12C

Geant4 simulations -4 2 -1 Φp(1 TeV) ~ 10 (m sr s GeV) -7 2 -1 Φe(1 TeV) ~ 10 (m sr s GeV)

If only 1 proton over 1000 is misinterpreted as an electron, we would end up with a 100% contamination in electron flux!!

The requirement for CALET is to be able to select electron and proton events such that proton contamination in electron sample is ~ %

N sel N ϵ ϵ ϵ 102 = e = e e =10−3 e e =105 Rejection power sel ϵ ϵ p ϵ p N p N p p

Selection efficiency