1. 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

2. 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
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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.

3. 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
※ mn0  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:

4. Kuo-Sheng Nuclear Power Plant
KS NPS-II :
2 cores X 2.9 GW
KS n Lab:
28 m from
core#1

5. 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

6. Kuo Sheng Reactor Neutrino Laboratory
Front Gate
Front View
(cosmic vetos, shieldings,
control room …..)
Inner Target Volume

7. 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)

8. 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]

9. 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

10. KS/P1/Ge/mn Data Data Volume: HPGe Performance: Analysis:
 Total 200/60 days ON/OFF [ reported here : 179/50 ON/OFF ]
HPGe Performance:
 kg mass
 0.4 keV 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

11. KS/P1/Ge : Spectra & Residual
Based on 170/50 days of Reactor ON/OFF data
No anomalous structures or residuals

12. KS/P1/Ge/mn : Prelim. Results
Fit OFF spectra to fOFF
E/keV fOFF c2/dof
p /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 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 : eV]
Residual Plot

13. Reactor mn(ne) Sensitivities
Gn Sensitivities

14. 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

15. 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