Energy Resolution of a Parallel- Plate-Avalanche-Chamber Kausteya Roy Professors E. Norbeck and Y. Onel

Background: Overview of Particles Basic types: fermions and bosons Fermions- particles of matter, half integral spins Types of fermions –Leptons, weakly interacting particles, ex: electron –Hadrons- made up of quarks, strongly interacting particles, types such as baryons, mesons –Ex of baryons: protons, neutrons Bosons- particles of force, integral spins Fit into the Standard Model theory

Background: Future of Particle Detection Standard Model accounts for three of the Four basic forces Electromagnetic- photon Weak Nuclear- W boson Strong Nuclear- gluon Gravitational force is unaccounted for Theorized-Higgs boson and Graviton

Background: General Principle of Electromagnetic particle detectors Incoming particle decays into charged leptons or baryons Detectable using magnetic fields F=qvB, where q= charge on particle Other types: decelerate through a Voltage, such that qV=(1/2)mv 2, or for relativistic speeds qV=mc 2 γ PPAC is a type of proportional counter, which uses wires to conduct signals

Background: A Future Particle detector PPAC is a type of low pressure gas detector Two parallel plates filled with low pressure gas and a relative electric potential of 930 volts Electrons enter chamber and generate shower of knocked off electrons Called electron “avalanche” Since an individual electron has too small a charge to be measured, an avalanche is required to measure charge Avalanche moves in direction determined by Voltage, which generates an electric field across plates

Background

Background: Electron Avalanche Formula General form of Townsend’s law N(α,x)= exp(α,kx) where a is the Townsend coefficient and x is the distance within the detector For electron diffusion within electric field W= (-4π/3)(e/mN)(E/P) S v^2/o(m)df dv/dv

Advantage of PPAC Resistant to Radiation Simple to use Signal termination expected to be quick Distinct pulses Easy to analyze electronically High GeV Detection

Purpose of Experiment Test for PPAC time resolution Time required for second PPAC to register signal-expected 50nsec Test for PPAC Energy Resolution Closeness of pulses in both PPACs Test of voltage gain-expected 30mV

Electronic Setup (Timing Resolution) The Radioactive source emits Beta particles, which emulate a high energy hadron shower.

Electronic Setup (Energy Resolution) Preliminary – Electronics Energy resolution

Data Collection: Useful Equations The equipment detects voltage, as well as time continuum for pulse Energy derivation E= (1/R) t1 S t2 V(t) dt R= Test Resistance, usually 50 ohms

Data: Timing Resolution Avg Signal 15nsec

Data: Energy Resolution Avg. Gain: 55mV

Data: Further Testing Testing at Fermi lab 4 TeV proton beam Further test-beams with pions and mesons Pions- higher charge than electrons Mesons- quark, anti- quark pair

Conclusions Good Timing resolution-less than expected Preliminary photon testing shows good energy resolution Higher Voltage Gain than expected

Conclusions Data collection at 10kHz, given sufficiently fast support electronics Good frequency for current particle accelerators

Future Plans PPAC detector system Updated version of Stanford Linear Accelerator Center Use at CERN

Future Plans Multi-pixelated PPAC

Special Thanks To: Professor Yasar Onel Professor Edwin Norbeck Jonathan Olson All SSTP staff and students Will Swain Fermi National Accelerator Laboratory