Kuo-Sheng(國聖) Reactor Neutrino Lab. ※ Overview A Search of Neutrino Magnetic Moment at the Kuo-Sheng Power Plant in Taiwan TEXONO Collaboration : Overview Kuo-Sheng(國聖) Reactor Neutrino Lab. ※ Overview ※ Magnetic Moments Results with ULB-HPGe ※ Other analysis Status and Plans Henry T. Wong / 王子敬 Academia Sinica /中央研究院 @
TEXONO* Collaboration W.C. Chang¶, C.P. Chen, K.C. Cheng, H.C. Hsu, F.S. Lee, S.C. Lee, S.T. Lin, D.S. Su, P.K. Teng, W.S. Tse¶, H.T.K. Wong†, C.S. Wu, S.C. Wu Academia Sinica, Taipei, Taiwan W.P. Lai Chung Kuo Institute of Technology, Taipei, Taiwan C.H. Hu, J.M. Huang, W.S. Kuo, T.R. Yeh Institute of Nuclear Energy Research, Lungtan, Taiwan H.B. Li, M.Z. Wang¶ National Taiwan University, Taipei, Taiwan J.H. Chao, J.H. Liang National Tsing Hua University, Hsinchu, Taiwan Z.M. Fang, R.F. Su Nuclear Power Station II, Kuosheng, Taiwan M. He, S. Jiang, L. Hou, H.Q. Tang, B. Xin, Z.Y. Zhou¶ Institute of Atomic Energy, Beijing, China J. Li†, Y. Liu, Z.P. Mao, J. Nie, J.F. Qiu, H.Y. Sheng, P.L. Wang, X.W. Wang, Q. Yue, D.X. Zhao, J.W. Zhao, P.P. Zhao, S.Q. Zhao, B.A. Zhuang Institute of High Energy Physics, Beijing, China Z.S. Liu, Z.Y. Zhang Institute of Radiation Protection, Taiyuan, China T.Y. Chen Nanjing University, Nanjing, China J.P. Cheng, D.Z. Liu Tsing Hua University, Beijing, China C.Y. Chang, G.C.C. Chang† University of Maryland, Maryland, U.S.A. † Co-Prinicipal Investigators ¶ Project Leaders Ph.D. Students *Taiwan EXperiement On NeutrinO Home Page @ http://hepmail.phys.sinica.edu.tw/~texono/ HISTORY Initiate : Chang Chung-Yung 1996 First Collab. Meeting/Official Start : October 1997 First Paper : October 1998 KS Reactor Experiment Installation : June 2000 First Ph.D. : Liu Yan , July 2000 First Physics Data Taking : June 2001.
TEXONO Overview Goals : Program: Neutrino and Astroparticle Physics Starting phase: 1st particle physics expt in Taiwan Build up a Qualified Group 1st big research Coll. % Taiwan & China Kuo-Sheng Reactor Neutrino Lab. ※ reactor : high flux of low energy electron anti-neutrinos ※ mn0 anomalous n properties & interactions ※ n’s strange & full of surprises study/constraint new regime wherever possible experimentally R&D Projects diversified program ※ reactor program as base ※ explore various future scenarios Program:
Kuo-Sheng Nuclear Power Plant KS NPS-II : 2 cores X 2.9 GW KS n Lab: 28 m from core#1
Kuo-Sheng Neutrino Laboratory High flux of ne (also ….. ne ) Modular Design : independent detector, electronics, shielding high-Z target, large re Improved detector performance: good energy & spatial resolution, low threshold, a/g separation Elaborate electronics+DAQ+control sys. complete record of pulse shape + timing info. Elaborate Shieldings radon purge & 4p cosmic veto Configuration: Modest yet Unique Flexible Design: Allows different detectors conf. for different physics
Kuo Sheng Reactor Neutrino Laboratory Front Gate Front View (cosmic vetos, shieldings, control room …..) Inner Target Volume
ULB-HPGe + Anti-Comptons KS Expt. : Period I Configuration Period I : June 01 – April 02 (60 days OFF) Shielding & Veto [one side] ULB-HPGe + Anti-Comptons CsI(Tl) Array (46 kg)
KS Expt: Period I Detectors ULB-HPGe [1 kg] CsI(Tl) [46 kg] FADC Readout [16 ch., 20 MHz, 8 bit] Multi-Disks Array [600 Gb]
mn with Reactor ne mn Experimental Probe: parametrize possible niL njR + g vertices both i = j “diagonal” & i j “transition” moments Experimental Probe: Study ne + e- nX + e- Focus on low recoil energy ※ sm T–1 ※ decouples SM “background” [ ……… LE reactor f(ne) not accurately known] Look for Excess in Reactor ON/OFF Neutrino Radiative Decay (Gn): sm & Gn related: same vertices – real g for Gn Electron Recoil Spectra
KS/P1/Ge/mn Data Data Volume: HPGe Performance: Analysis: Total 200/60 days ON/OFF [ reported here : 179/50 ON/OFF ] HPGe Performance: 1.06 kg mass 0.4 keV RMS @ 10 keV 5 keV threshold [Unique Data] Range of O(1 cpd) [counts kg-1 day-1 keV-1] background c/f Dark Matter expt. Analysis: Cosmic Veto (5 ms gate) Anti-Compton (Well+Base detectors) Pulse Shape Disc. (veto elect. noise, accidentals) Efficiencies Normalization: (to <0.3%) DAQ book-keeping Monitor random triggers Monitor residual 40K peaks Monitor 10 keV Ga X-rays peak
KS/P1/Ge : Spectra & Residual Based on 170/50 days of Reactor ON/OFF data No anomalous structures or residuals
KS/P1/Ge/mn : Prelim. Results Fit OFF spectra to fOFF E/keV fOFF c2/dof 12-61 p5 80/96 Fit ON spectra to fOFF + fSM + k2 fMM [10-10 mB] [using best-fit values of (fOFF;dfOFF)] Fit Results (@ c2/dof = 41/49 ): k2 = -0.5 1.4 (stat.) 0.3 (sys.) Limits derived : mn < 1.4 (1.0) X 10-10 mB @ 90(68)% C.L. Further Work : complete analysis of full data set more cross-checks & error analysis prepare Period-II data taking [Aim of analysis threshold: ~ 5 keV] study “ultra-low” energy Ge prototype [threshold : 200-300 eV] Residual Plot
Reactor mn(ne) Sensitivities Gn Sensitivities
KS/P1 Analysis HPGe : exploit the low threshold data Established Problem: mn and Gn for ne via : ne + e nx + e Speculative Analysis: ※ study ne flux from reactor due to neutron excitation producing e.g. 51Cr, 55Fe [distinct energy & timing …..] study mn & Gn for ne ※ anomalous Neutrino Interactions in Matter e.g. anomalous energy deposition X (>eV) ne + N nx + N + X [similar analysis as accelerator nm] ※ study possible nuclear transitions e.g. 73Ge* decays by 2g’s separated by t1/2=4.6 ms CsI(Tl) : Technical Run Event Reconstruction Background Studies Optimize for P2
Summary TEXONO Collaboration: Kuo-Sheng Neutrino Lab.: Built-Up and Growing Kuo-Sheng Neutrino Lab.: Established & Operational ※Modular & Flexible Design Physics Data Taking since June 01 ※Unique HPGe Low Energy Data ※ Bkg Level ~ Underground CDM Expt. Expect Results on mn (Gn) soon ※ Other speculative analyses under way Preparation of Period-II DAQ Improved HPGe Conf. Commissioning 150+ kg CsI(Tl) [+ s(ne) …] Diversified R&D Program in parallel