1. Kuo-Sheng(國聖) Reactor Neutrino Lab.
Low Energy Neutrino Physics at the Kuo-Sheng Reactor Neutrino Laboratory in Taiwan
TEXONO Collaboration : Overview
Kuo-Sheng(國聖) Reactor Neutrino Lab.
※ Magnetic Moments Results with ULB-HPGe
※ Other topics being pursued/in preparation
R&D Program
Henry T. Wong / 王子敬
Academia Sinica /中央研究院
TAUP-03, Seattle

2. Program: Poineering Efforts : TEXONO Overview
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 possible experimentally
 explore possible new detection channels
R&D Projects
Poineering Efforts :
KS Expt: 1st particle physics experiment in Taiwan
TEXONO Coll. : 1st big research Coll. % Taiwan & China
[feature report in Science, Vol. 300, 1074 (2003) ]

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

4. 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

5. 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)

6. 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]

7. 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

8. KS/P1/Ge/mn : Results Total 4712/1250 hours ON/OFF
 No residual observed
Range of O(1 cpd) background
c/f Dark Matter expt.
Fit OFF spectra to p5
Measure [fOFF;dfOFF ]
c2/dof = 80/96 )
Fit ON spectra to
fOFF + fSM + k2 fMM [10-10 mB]
Fit Results c2/dof = 48/49 ):
k2 = -0.4  1.3 (stat.)  0.4 (sys.)
Limits derived :
mn < 1.3 (1.0)  mB
@ 90(68)% C.L.
H.B. Li et al., TEXONO Coll., Phys. Rev. Lett. 90, (2003)

9. Reactor mn(ne) Sensitivities
Gn Sensitivities

10. Prototype ULE-HPGe [5 g] :
Status & Plans
HPGe [1 kg] :
mn + Gn : x2 more data
improved background & analysis
study ne flux from reactor
dominated by 51Cr : ~ (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

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

12. 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

13. Period-2 CsI(Tl) Array : 186 kg, 93 crystals
Single Crystal QL Vs QR (Raw Data)
Region of Interest for SM s(ne)

14. “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 Oct 03
study appl. in nN coherent scattering and Dark Matter searches
Threshold ~ 200 eV
PSD Cut
Signal Band
Threshold < 100 eV

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

16. Also ………. Road tunnel at 2 km 100 m rock overburden
Geographically possible for medium baseline experiment :
Access to Plant established
Road tunnel at 2 km
100 m rock overburden

17. Summary & Outlook TEXONO Collaboration:  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) …]
 study potentials for scoh(nN) ……
Diversified R&D Program in parallel