1. Searching for possible hidden chambers in the Pyramid of the Sun ICRC-2007, Mérida

2. Pyramid of the Sun

3. Archeological problem - Three man-made tunnels (1920-50): no internal structure. - Radón (1997) measurements: no large cavities (?) - Moon Pyramide (+2002 results): Internal structure and large tumb!

4. Alvarez experiment Giza

5. Muon attenuation method Sensitivity Resolution Measurement vs. simulation

6. Simulation uncertainties Aereal level diagramDigitalization External shape

7. Internal density

8. GEANT-4 simulation Hypothetical chamber Smith Tunnel SBD method

9. Projections Smith Tunnel

10. Components: - Scintillators - Multiwire PC’s - WFD readout - Telemetry Detector design

11. Laboratory tests

12. WFD readout

13. On-site work Electricity Entrance limitation Laboratory

14. Current status - GEANT-4 simulations - Electrical power cabling (~1 km) - Detector shack and ventilation system (controlled humidity and temperature) - Commissioning of scintillation detectors - Commissioning of individual MWPC’s - Wireless communications - Laboratory tests of ensemble  - Experiment 

15. Participants Physics Institute Researchers Rubén Alfaro M. Ernesto Belmont M. Varlen Grabski Arnulfo Martínez D. Arturo Menchaca R. Matías Moreno Y. Andrés Sandoval Technician Mario Rangel Students Emilio Arrieta G. Ana Delia Becerril Azucena Cervantes Juan Manuel López Roberto Núñez C. Rémy Reche Esteban Rodríguez Edgar Vázquez Anthropology Institute Researchers Linda Manzanilla N. Luis Barba P. Economic support DGAPA-UNAM CONACYT