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Detecting Air Showers on the Ground

Detecting Air Showers on the Ground. Outline Air Shower Physics Extensive Air Showers Gamma/Hadron sep. Why use EAS Detectors Detecting showers on the ground Water Cherenkov - Milagro RPCs – ARGO. Milagro. Extensive Air Shower Development. From Ralph Engel. Extensive Air Shower.

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Detecting Air Showers on the Ground

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  1. Detecting Air Showers on the Ground Outline • Air Shower Physics • Extensive Air Showers • Gamma/Hadron sep. • Why use EAS Detectors • Detecting showers on the ground • Water Cherenkov - Milagro • RPCs – ARGO Milagro University of Maryland

  2. Extensive Air Shower Development University of Maryland

  3. From Ralph Engel University of Maryland

  4. Extensive Air Shower University of Maryland

  5. Effect of Altitude ARGO Milagro Low Energy Threshold Requires High Altitude University of Maryland

  6. Milagro ARGO 10 TeV 1 TeV Cascade Development University of Maryland

  7. Gamma Shower 2 TeV (movies by Miguel Morales) Blue – Electrons Muons – Yellow Pions – Green Nucleons – Purple University of Maryland

  8. Proton Shower 2 TeV (movies by Miguel Morales) Blue – Electrons Muons – Yellow Pions – Green Nucleons – Purple University of Maryland

  9. Ngammas Nelectrons Primary Energy (GeV) Gamma Shower Content University of Maryland

  10. Lateral distribution of EM energy and muons EM energy from 500 GeV g Muons from 500 GeV Proton Muons from 500 GeV Proton EM energy from 500 GeV g University of Maryland

  11. Techniques in TeV Astrophysics Non-pointed instruments Pointed instruments High energy threshold Moderate background rejection Large field of view (~2sr) High duty cycle (>90%) Good for all sky monitor and for investigation of transient and diffuse sources. Low energy threshold Good background rejection Small field of view Low duty cycle Good for sensitive studies of known point sources. University of Maryland

  12. University of Maryland

  13. Sampling the Shower • Water Tanks • Scintillators University of Maryland

  14. Cherenkov Radiation When a charged particle moves through transparent media faster than speed of light in that media. Cherenkov radiation Cone of light University of Maryland

  15. Cherenkov Radiation University of Maryland

  16. University of Maryland

  17. Auger University of Maryland

  18. EAS g - Tibet University of Maryland

  19. IceTop University of Maryland

  20. ARGO University of Maryland

  21. Limited Streamer Tubes University of Maryland

  22. ARGO Design University of Maryland

  23. RPC Satisfied the Requirements on Element of Carpet Resistive Plate Chamber Low cost , high efficiency, high space & time resolution (<1ns), easy access to any part of detector, robust assembling, easy to achieve >90% coverage, mounting without mechanical supports. RPC PAD STRIP 2850x1258mm2 University of Maryland

  24. ARGO Building University of Maryland

  25. DAQ RPC University of Maryland

  26. ARGO Events ARGO will be a very capable detector when completed in several years! University of Maryland

  27. 8 m 50m 80m Milagro 450 Top Layer 8” PMTs 273 Bottom Layer 8” PMTs University of Maryland

  28. Milagro Site University of Maryland

  29. Milagro University of Maryland

  30. Milagro Outriggers University of Maryland

  31. Shower hitting the pond at an angle University of Maryland

  32. 2 Tev Proton Shower hitting the pond University of Maryland

  33. 2 Tev E/M Shower hitting the pond University of Maryland

  34. Angle Reconstruction For large showers, the angle can be reconstructed to better than 0.50o.(However, there are systematics associated with core location) University of Maryland

  35. Events University of Maryland

  36. Shower Curvature University of Maryland

  37. Conical shape from ARGO University of Maryland

  38. Curvature Correction Core Location Error vs True Core Distance from Center of Pond • The shower front is not a plane, but is curved about the shower core • Times of individual PMTs are adjusted based on the distance to the shower core Without Outriggers Core Error (meters) Core Distance (meters) Curved Shower Front 7ns/100m With Outriggers Core Error (meters) University of Maryland Core Distance (meters)

  39. Why Use EAS Detectors to Study Gammas • Transient Sources • GRB’s • Don’t know when or where to look • Some indications of 2nd hard comp. • Variable Sources • Diffuse Sources • Galactic Plane • New Sources University of Maryland

  40. P g Gamma – Hadron Separation University of Maryland

  41. Tibet III + MUON 8,640 m2 University of Maryland

  42. g miniHAWC mini- High Altitude Water Cherenkov experiment University of Maryland

  43. Detector Layout HAWC: 5625 or 11250 PMTs (75x75x(1 or 2)) Single layer at 4m depth or 2 layers at Milagro depths Instrumented Area: 90,000m2 PMT spacing: 4.0m Shallow Area: 90,000m2 Deep Area: 90,000m2 miniHAWC: 841 PMTs (29x29) 5.0m spacing Single layer with 4m depth Instrumented Area: 22,500m2 PMT spacing: 5.0m Shallow Area: 22,500m2 Deep Area: 22,500m2 Milagro: 450 PMT (25x18) shallow (1.4m) layer 273 PMT (19x13) deep (5.5m) layer 175 PMT outriggers Instrumented Area: ~40,000m2 PMT spacing: 2.8m Shallow Area: 3500m2 Deep Area: 2200m2 University of Maryland

  44. 30 GeV 70 GeV 230 GeV Gammas 270 GeV 20 GeV 70 GeV Protons Gamma/Hadron Separation Size of miniHAWC Size of Milagro deep layer University of Maryland

  45. Curtains • A high altitude version of Milagro would trigger at >10kHz. Need to control spurious triggers due to single muons. • Install curtains to optically isolate the PMTs. • Intrinsic Gamma hadron separation University of Maryland

  46. miniHAWC 5 m 170m 4m 6m 4.5-5.0 m 150m MiniHAWC University of Maryland

  47. Tibet – 4300m • ARGO University of Maryland

  48. Comparison of Effective Areas 50 Tube Trigger University of Maryland

  49. The Diffuse Galactic Plane in miniHAWC and HAWC Use Neutral H map to trace out VHE Gamma-Ray flux. Normalize to Milagro observed TeV diffuse emission from the Galactic plane. University of Maryland

  50. Conclusions on Air Shower Detectors • They are complimentary to ACTs • Their features of wide field of view and continuous observation gives them the ability to: • Observe transient sources • Observe diffuse objects • Discover new objects University of Maryland

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