120 likes | 268 Views
Study of Inverse Beta Decay Events. I. S. Jeong. K. K. Joo, J. Y. Kim, I. T. Lim(CNU). Contents & Status Summary. “Weighted Average Method” to reconstruct a vertex Energy Reconstruction Energy Resolution(now developing)
E N D
Study of Inverse Beta Decay Events I. S. Jeong K. K. Joo, J. Y. Kim, I. T. Lim(CNU)
Contents & Status Summary • “Weighted Average Method” to reconstruct a vertex • Energy Reconstruction • Energy Resolution(now developing) • Neutron Signal Separation on the Inverse Beta Decay(hereinafter refered to as “IBD”) • Neutron Vertex Reconstruction • Calculation of a distance between Neutron and Positron
Neutron Signal Separation on the Inverse Beta Decay Energy recon-result : Positron landau fit Neutron gaussian fit Number of Events 6MeV> Gd capture H capture Reconstructed Energy
Con’t - Exponential fit on the time distribution Positron timing distribution Neutron timing distribution # of events(gamma/entry) Zoom up PMT hit time by photon(ns) 0.6m 0.7m Target PMT R5912 Max~27.5cm R7081 Max~30.0cm Reflective index ~ 1.47 + Target region(e & neutron)
Neutron Vertex Reconstruction Weighted Averaged method : - redefined by I. S. Jeong conditions: PMT gamma capture time number of PMT hits Reconstructed Vertex # of events Ex)The number of citations on the 300th PMT = 23 Total number of PMT hits = 400 The weighting factor on the 300th PMT ~ 0.73 Xpos Ypos Zpos Nvertex_X Nvertex_Y Nvertex_Z
Con’t - Confirmation Blue:Reconstructed Red:Generated Overlapped Sigma_dx = 191.6±2.7mm Sigma_dy = 197.7±2.9mm Sigma_dz = 194.6±3.0mm # of events for a positron Sigma_dx = 90.54±0.76mm Sigma_dy = 90.06±0.71mm Sigma_dz = 90.41±0.77mm Nvertex_x - Xpos Nvertex_y - Ypos Nvertex_z - Zpos
Calculation of a Distance between Two Vertexes of Neutron and Positron Reconstructed Neutron Vertex – Generated Positron Vertex # of events Generated Neutron Vertex – Generated Positron Vertex # of events Reconstructed difference distance(mm) Reconstructed Neutron Vertex – Reconstructed Positron Vertex
Summary • Confirmation of IBD events • Sigma(x,y,z)<20cm through the reconstruction of a neutron vertex • Successful applying WM to the reconstruct a neutron vertex and to calculate a distance between neutron and positron • Understanding of a neutron’s behavior(why it is starting to appear around 5ns) Plan & To Do • To find some relationship(between space & reconstructed energy)through the energy reconstruction
Neutrino History • 1930: W. Pauli postulates the existence of a neutral particle produced in nuclear β decay along with the electron • 1932: E. Fermi names Pauli’s particle the “neutrino” • 1933: Observed electron spectrum implies neutrino mass is much smaller than that of the electron Neutrino assumed to be massless
RENO detector • Target 15t 0.1% Gd-LS ~140cm • Gamma Catcher ~60cm • Oil Buffer ~70cm, 537 (8, 10inch) PMTs • Water veto ~1m