*Taiwan EXperiement On NeutrinO (台灣微中子實驗) Low Energy Neutrino Physics at the Kuo-Sheng Reactor Neutrino Laboratory in Taiwan TEXONO Collaboration : Overview Kuo-Sheng(國聖) Reactor Neutrino Laboratory ※ Facilities  Magnetic Moments Results (See H.B. Li’s Talk) ※ Research Topics R&D Program Henry T. Wong / 王子敬 Academia Sinica /中央研究院 @ CosPA 2003 *Taiwan EXperiement On NeutrinO (台灣微中子實驗) Home Page @ http://hepmail.phys.sinica.edu.tw/~texono/

TEXONO* Collaboration W.C. Chang, K.C. Cheng, M.H. Chou, H.C. Hsu, C.H. Iong, G.C.Jon, F.S. Lee, S.C.Lee, H.B. Li, V. Singh, D.S. Su, P.K.Teng, H.T.K.Wong,  S.C. Wu Academia Sinica, Taipei, Taiwan W.P. Lai Chung Kuo Institute of Technology, Taipei, Taiwan C.H. Hu, W.S. Kuo, T.R. Yeh Institute of Nuclear Energy Research, Lungtan, Taiwan H.Y. Liao, S.T. Lin, M.Z. Wang National Taiwan University, Taipei, Taiwan F.K. Lin National Tsing Hua University, Hsinchu, Taiwan Z.M. Fang, R.F. Su Nuclear Power Station II, Kuosheng, Taiwan J. Bao, K.J. Dong, S. Jiang, L. Hou, Y.H. Liu, H.Q. Tang, B. Xin, Z.Y. Zhou Institute of Atomic Energy, Beijing, China J.Li, Y. Liu, J. Nie, Z.P.Mao, J.F.Qiu, H.Y.Sheng, P.L.Wang, X.W. Wang, D.X.Zhao, P.P.Zhao, B.A.Zhuang 　 Institute of High Energy Physics, Beijing, China J.Q. Lu, T.Y. Chen Nanjing University, Nanjing, China Y. An, D.Z. Liu, Q. Yue, Y.F. Zhu Tsing Hua University, Beijing, China C.Y. Chang, G.C.C. Chang University of Maryland, Maryland, U.S.A. Co-Prinicipal Investigators Ph.D. Students 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. First Physics Results: Dec 2002.

Poineering Efforts : “Zero-Background Experiment” ! TEXONO Overview Program: Kuo-Sheng Reactor Neutrino Laboratory ※ reactor : high flux of low energy electron anti-neutrinos ※ mn0  anomalous n properties & interactions ※ n physics full of surprises , need intense n-source  study/constraint new regime wherever experimentally accessible  explore possible new detection channels R&D Projects Poineering Efforts : “Zero-Background Experiment” ! KS Expt: 1st large-scale particle physics experiment in Taiwan TEXONO Coll. : 1st big research Coll. % Taiwan & China [feature report in Science, Vol. 300, 1074 (2003) ]



Kuo-Sheng Nuclear Power Plant KS NPS-II : 2 cores  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

Kuo Sheng Reactor Neutrino Laboratory Front Gate Front View (cosmic vetos, shieldings, control room …..) Configuration: Modest yet Unique Flexible Design: Allows different detectors conf. for different physics Inner Target Volume

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]

Kuo Sheng Reactor Neutrino Laboratory : First Results  See Hau-Bin Li ‘s Talk Citation in AIP’s Physics News Update #631-1 (2003).

Reactor mn(ne) Sensitivities Gn Sensitivities

KS Physics Program : Period I & II HPGe [1 kg] : mn + Gn : x2 more data from PRL improved background & analysis study ne flux from reactor dominated by 51Cr : ~ 10-3 (prelim.) study possible nuclear transitions e.g. 73Ge* decays by 2g’s separated by t1/2=4.6 ms CsI(Tl) [186 kg] : attempt measurement of Standard Model s(nee-)  sin2qw at MeV range Prototype ULE-HPGe [5 g] : threshold < 300 eV  ~ 100 eV explore potentials on nN coherent scattering & CDM

Reactor Neutrino Interaction Cross-Sections P2: SM (ne) > 2 MeV P1: MM (ne) 1-100 keV P3+: Coh. (nN) < 1 keV

Reactor as ne Source Fission Material Fission Products Neutrons odd-odd nuclei Structural materials of reactor Electron capture or + decay ( neglected ) νe Emission Captured Mostly rich in neutrons ¯ Decay back to  stable valley Anti-neutrino Emisson

Tagging of 73Ge ½- 2g transitions: Event-by-Event background-free tag with PSD To do : Reactor ON/OFF analysis on the system ~1 s before the transition To look for : possible n-induced nuclear transitions

CsI(Tl) Array : Highlights 40 cm length (longest commercial prod.) Energy+3D info:  10% FWHM at 660 keV  s(z) <2 cm @ E>250 keV Detector Threshold ~ 20 keV PSD for g/a : > 99% Intrinsic Purity :  238U/232Th < 10-12 g/g (equil.)  40K < 10-10 g/g cosmic muon events on-site @ 46 kg target Full Detector: 186 kg target on-site for Period-II DAQ with large dynamic range

Period-2 CsI(Tl) Array : 186 kg, 93 crystals Single Crystal QL Vs QR (Raw Data) Z = 0 cm Z =40 cm 208Tl 40K 137Cs Region of Interest for SM s(ne)

“Ultra-Low-Energy” HPGe Prototype mass 5 g ; can be constructed in multi-array form 55Fe+Ti back-scattered Spectra : noise edge at 200 eV threshold <100 eV after modest PSD background measurement on-site Nov 03 study appl. in nN coherent scattering and Dark Matter searches

ULE-HPGe Prototype Results PSD Cut Threshold ~ 100 eV Threshold < 100 eV Signal Band

R&D Projects Upgrading FADCs (+ FPGA etc. capabilities…..) Explore New Detectors Scenarios (LEn, CDM …)  other crystal scintillators  ultra low energy HPGe [ O(100 eV) threshold ] Feasibility Studies on CsI(Tl) for Dark Matter Searches  Approved Experiment @ Korea by KIMS Coll. Upgrading FADCs (+ FPGA etc. capabilities…..)  for LEPS @ SPring8 Trace Radio-purity with AMS ( Accelerator Mass Spectrometry)  1st goal : sensitivity of 10-14 g/g in 40K Sono-Luminescence Project (inter-disciplinary)

CsI(Tl) for CDM Searches Potential Merits: Better PSD for g/a separation than NaI(Tl) Minimal passive materials Large target mass possible (c/f em-calor. 40 tons) Highlights of R&D Program: Quenching Factor measurements with neutron beam  lowest threshold data 1st direct measurement of diff. cross section in heavy nuclei PSD studies with Neural Net. & Max. Likelihood  improve conventional methods N KIMS Expt. :  200 kg CsI(Tl) for CDM in S. Korea

TEXONO/KS FADC for SPring8/LEPS 40 MHz ; 12 bit ; 32 ch/module @ 9 U VME [ c/f KS FADC : 20 MHz ; 8 bit ; 16 ch/module ] On-board processing with FPGA 1000 channels used in TPC in LEPS Expt. @ SPring8 TPC for LEPS @ SPring8 Mixed signal FADC Adapter Board 40 MHz sampling rate. 10 bits resolution with 2Vp-p dynamic range. Clock distribution with Phase Lock Loop circuit. On Board digital signal delay and Real-Time ZERO-Suppression. High capacity First In First Out Memory. Easy to use with high density connector. (cosmic muon)

Trace Radio-purity with AMS Based at AMS facilities @CIAE with 13 MV Tandem Potential Merits:  small samples, quick  versatile on sample choice  sensitive to a/b emitters  sensitive to stable isotope & extrapolate (e.g. 39K)  >103 improvements over ICP-MS [.. once prescriptions are known. ] Status :  demonstrate 129I/127I < 10-12 g/g  measure 40K~10-10 g/g in CsI (powder) Sensitivity goal : 10-14 g/g Future :  different bases e.g. liquid scintillator  87Rb …… [238U / 232Th series after Tandem upgrade]

Sonoluminescence Project a frontier subject with possible surprises new directions : to explore subjects we do not know Table-top experiments, pursue-able in several labs  balance the other big & long time-scale projects  use HEP approaches Status :  produce steady SL  integrate DAQ  study physics  identify research topics …….. SL Typical Cycle SL Typical Set-Up

SonoLum Pulse

Also ………. Road tunnel at 2 km 100 m rock overburden Geographically possible for medium baseline experiment for “q13” : Easy reach from city Access to Plant established Road tunnel at 2 km 100 m rock overburden Contacts with International Team

TEXONO STATUS 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. Results published on mn (Gn)  Other analyses under way Period-II DAQ  Improved HPGe Conf.  186 kg CsI(Tl) [s(ne) …]  LEGe: study potentials for scoh(nN) Diversified R&D Program in parallel

Summary & Outlook Neutrinos are important but strange objects history of n physics full of surprises ! Strong evidenceS of massive n’s & finite mixings Physics Beyond the Standard Model ! More experiments & projects coming up EVEN MORE EXCITEMENT ! TEXONO is also a (modest) part of it Tremendous Pleasure & Pressure !