Measurement of arrival time of particles in extens

Authors: S K Gupta J Christiansen Y Hayashi A Jain P K Mohanty K C Ravindran B Satyanarayana

Publish Date: 2012/10/13

Volume: 35, Issue: 3, Pages: 507-526

PDF Link

Abstract

Arrival time of particles in an extensive air shower EAS is a key physical parameter to determine its direction EAS direction is useful for studies of anisotropy and composition of cosmic rays and search for multiTeV γrays sources Accurate timing may be used to search exotic phenomena such as production of new particles at extremely high energies available during early stages of development of EAS and also for detecting subrelativistic hadrons in EAS Time to digital converters TDCs are used to perform this task Traditional TDCs operate in the STARTSTOP mode with limited dynamic range and singlehit capability With the advent of high luminosity collider LHC need for TDCs with large dynamic range multihit capability and TRIGGERED mode of operation became necessary A 32 channel TDC was designed for the GRAPES3 experiment on a CAMAC platform around TDC32 an ASIC developed by microelectronics group at CERN Geneva Four modules were operated in the GRAPES3 experiment Here we present details of the circuit design and their performance over several years The multihit feature of this device was used to study the time structure of particles in the EAS on time scale of ~1 μs The distribution of time intervals in the multihit data shows an exponential profile with a time constant of ~370 ns These delayed particles are likely to be neutrons produced in the EAS core that were recorded in the scintillator detectors following the relativistic EAS frontWe acknowledge the outstanding contributions of K Manjunath and C Ravindran in wiring testing and installation of the G3TDC modules We thank GP Francis V Jeyakumar and K Ramadass for their timely help in the fabrication of several mechanical components used and for the assembly of these modules We also thanks PK Nayak for his extensive help during the preparation of this manuscript Stimulating discussions with SR Dugad deserve a special mention This work is dedicated to the memory of our brilliant colleague late S Karthikeyan who had made significant contributions to this as well as several other GRAPES3 activities prior to his tragic demise in a road accident

Keywords: