Upgrades to the Pierre Auger Observatory Jim Matthews

Upgrades to the Pierre Auger Observatory Jim Matthews Louisiana State University Snowmass, Minneapolis, 30 July 2013 1

Argentina Australia Bolivia* Brasil Croatia Czech Republic France Germany Italy Poland Mexico Netherlands Portugal Romania* Slovenia Spain United Kingdom USA Vietnam* ~ 500 Scientists 19 Countries 2

Aims of the experiment • Measure the energy spectrum of high energy cosmic rays up to and beyond energies of 1020 e. V • Determine the sources of these cosmic rays • Determine the elemental composition of cosmic rays • Study extensive air showers -> particle interactions 3

38° South, Malargüe, Mendoza, Argentina 4

Surface Arrays and Fluorescence Detection - Arrays: 24/7 operation, very large size (statistics) - Fluorescence: ‘calorimetry’ = good energy resolution (spectrum) 5

Surface Array 1650 detector stations 1. 5 Km spacing 3000 km 2 Fluorescence Detectors 4 Telescope enclosures 6 Telescopes per enclosure 24 Telescopes total 6

Improved! 7

(Only about 10% of all events can have Xmax measured directly) 8

Farrar, ICRC 2013, ar. Xiv: 1307. 5059, p. 52 Observe “too many” muons! 9

T. Pierog, ECRS 2012 10

Upgrades to the Pierre Auger Observatory Aim: to enhance muon measurements - composition sensitivity, shower development (hadron physics) How: 1. Faster Waveform sampling and extended dynamic range in the surface detectors 2. Direct muon detection 3. Improved Fluorescence duty cycle 4. (plus existing projects already underway) 11

30 Mpc – distance to center of local group (Virgo Cluster) p + (2. 7 o. K) p + ’s 12

log (flux) p E GZK -γ E ~ 5 x 1019 e. V log E 13

log (flux) p E Or: Source? -γ Fe Z = 26 Emax 26 x. Emax log E 14

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40 MHz Electronics Upgrade Increase the speed of the FADC by a factor of three; Increase dynamic range 120 MHz 16

Improvement in ability to reconstruct muon size 120 MHz 40 MHz p Fe Log (reconstructed/input) => Improvement in p/Fe separation: 1. 5 17

Improved dynamic range gets you closer to the core 18

Reconstructed Muons and Muon LDF 19

Scintillators near or under (or over) SD tanks 20

Muon Detection: RPCs 21

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RPC prototypes • First Lab Prototype • • 0. 5 x 1 m 2 0. 3 mm gaps Original RPC design for timing (st~200 ps) Main goal: test low gas flux • Second Lab Prototype • 0. 5 x 1 m 2 • 2 x 1 mm gap • Main Goal: • Optimize efficiency • Optimize signal 23

Muon signals : tank vs RPC proton, 1019. 5 e. V q=40 o Hits in RPC 24

Muon signals : tank vs RPC proton, 1019. 5 e. V q=40 o Muons Photons 25

RPC (and all muon detectors) help to distinguish photon primaries 26

Segmented Tank 27

Existing Enhancements at Auger: 24 km 2 28

The upgrades envisioned for the Pierre Auger Observatory focus on improved measurements of cosmic-ray composition from the ankle through the highest energies. In the next decade, Auger will roughly triple its present data set. But obtaining event-by-event composition measurements will be an order-of-magnitude increase in that kind of data. Improvements: 1. Understanding the flux suppression 2. Anisotropy/directional studies 3. Hadronic physics 4. Gamma-rays and neutrino identification 5. Reduced systematic uncertainties 29

Summary The Pierre Auger Observatory has been an extremely successful scientific program and investment. It exemplifies the misson statement of the DOE Cosmic Frontier initiative: “Using particles from space to explore new phenomena” by developing and employing “New techniques that complement accelerator-based research” Our international partners are excited to continue this work. So are all the US groups. 30