Energy Resolution of a Parallel-Plate-Avalanche-Chamber

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

2. 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

3. 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

4. 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)mv2, or for relativistic speeds qV=mc2γ • PPAC is a type of proportional counter, which uses wires to conduct signals

5. 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

6. Background

7. 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

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

9. 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

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

11. Electronic Setup (Energy Resolution) Preliminary – Electronics Energy resolution

12. Data Collection: Useful Equations • The equipment detects voltage, as well as time continuum for pulse • Energy derivation E= (1/R) t1St2 V(t) dt R= Test Resistance, usually 50 ohms

13. Data: Timing Resolution Avg Signal 15nsec

14. Data: Energy Resolution Avg. Gain: 55mV

15. 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

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

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

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

19. Future Plans • Multi-pixelated PPAC

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