1. The TEXONO Research Program on
Experimental Neutrino & Astroparticle Physics
Road Map in Neutrino Physics
Neutrino Electromagnetic Interactions
TEXONO Research Program
Kuo-Sheng Neutrino Laboratory
Low Energy Neutrino Physics at Kuo-Sheng
R&D Projects
Summary & Outlook
Henry T. Wong / 王子敬
Academia Sinica / 中央研究院 @
April 2005

2. Neutrino Physics Road-Map
L(n-mass)0
mn’s;Uij’s 0
n-Oscil.
mn’s
n-decays
0nbb
b-spect.dist.
anomal. int.
……….
Grand Unified Theories (GUT)
Structures & Compositions of Universe
Particle Physics
Nuclear Physics
Astrophysics
Cosmology
n’s as Probe

3. Neutrino Electromagnetic Properties : Magnetic Moments
requires mn0
e.g.
fundamental neutrino properties & interactions ; necessary consequences of neutrino masses/mixings ; a channel to differentiate Dirac/Majorana neutrinos (nD/nM)
look for surprises and/or constrain parameter space for model-building with future precision oscillation data
explore new neutrino sources ; understand known ones
explore new detection channels & techniques, low energy
explore roles of neutrinos in astrophysics

4. Particle Physics
※ (ni)L – (nj )R – g vertices described in general by:
eij and bij are the electric & magnetic dipole moments coupling ni & nj
constrained by symmetry principles, nD/nM, diagonal/transition moments (ni =/ nj ?) [ e.g. nM & i=j  b=e=0 ]
※ Experimental measureable “neutrino magnetic moment” depends on |nl > after oscillation distance L
Subtleties/Complications:
measureable is an effective/convoluted parameter (c.f. 0nbb)
physics information depends on exact |n> compositions at the detector

5. Experimental Manifestations
Minimally-Extended Standard Model with nD : mn VERY small
 many ways to significantly enhance it (nM, WR …..)
study consequences from the change of neutrino spin states in a (astrophysical) medium
1/T spectral shape in n-e scattering, T is electron recoil energy
Neutrino radiative decays
…………

6. Astrophysics Bounds/Indications
From:
Big Bang Nucleosynthesis degree of freedom
Stellar Cooling via
Cooling of SN1987a via nactive  nsterile
Absence of solar [KamLAND-03 < 2.8x10-4 ; n04: HE eventsstay tuned]
ranges of mn(astro) < – mB
Complications/Assumptions :
astrophysics modeling (e.g. Solar B-field)
Neutrino properties (e.g nD / nM ; no other anomalous effects)
Global treatment (e.g. effects from matter, oscillations ; interference/competitions among channels ……)

7. Magnetic Moments & Solar Neutrinos
For completeness/historical footnote ……
Magnetic Moments & Solar Neutrinos
ne produced in the Sun interact with B to become nx(xe), via spin-flavor precession(SFP), with or without resonance effects in solar medium.
used to explain anti-correlation of Cl-n data with Sun-spot cycles in late 80’s
scenario compatible with all solar neutrino data
KamLAND independently confirms LMA as the solution for solar neutrino problem  SFP cannot be the dominant contribution
[n data + LMA allowed region + no ]
 constrain  mn B dr : [Akhmedov et al., Miranda et al. …]
ranges of mn(solar) < – mB (after B modeling)

8. Direct Experiments
using sources understood by independent means : reactor n , accelerator n , n at detector , n-sources (future)
look for 1/T excess due to n-e scattering via mn channel over background and Standard Model processes
reactor n : reactor ON/OFF comparison to filter out background uncertainties
n : account for background spectra by assumptions/other constraints
limits independent of |n>final : valid for nD/nM & diag./tran. moments -- no modeling involved
interpretation of results : need to take into account difference in |n>initial

9. Solar n : SK & Borexino
※ SK spectral distortion over oscillation “bkg” [hep-ex/ ]
8B n
SK alone : mn(n ) < 3.6 X mB (90% CL)
+ all n data : mn(n-LMA ) < 1.3 X mB (90% CL)
+ KamLAND : mn(n-LMA ) < 1.1 X mB (90% CL)
※ Borexino/CTF spectral analysis [PLB 563,2003]
mainly 7Be n
bkg=0 : mn(n ) < 1.2 X 10-9 mB (90% CL)
Assume linear bkg + best fit :
mn(n) < 5.5 X mB (90% CL)

10. Accelerator n : LSND & DONUT
※ LSND [PRD 63, 2001]:
select “single electron” events
taking SM s(nm-e), measured s(ne-e)
 agrees with SM  set limit
※ DONUT [PLB 513, 2001]:
observed nt from Ds decays at expected level
look for “single electron” events at level >> SM s(n-e)
observed 1 event with 2.3 expected e=9%
limit: mn(nt) < 3.9 X 10-7 mB (90% CL)

11. Reactor Bugey : MUNU
CF4 TPC (total mass 11.4 kg; containment e~0.5 at 1 MeV)
excellent “single electron” event selection via 4p liquid scintillator & tracking
distinguish start/end of track & measure scattering angle w.r.t. reactor direction  measure neutrino energy
Reactor ON/OFF comparison  forward/background events comparison

12. MUNU data (66.6 d ON/16.7 d OFF) [PLB 564, 2003]
excess of counts < 900 keV ; NO explanations yet [fn(reactor) below 2 MeV not well-known]
limits depends on energy range taken :
Visual scan T > 700 keV
mn(ne) < 1.4 X mB (90% CL)
Visual scan T > 900 keV
mn(ne) < 1.0 X mB (90% CL)
Auto scan T > 300 keV
mn(ne) < 1.7 X mB (90% CL)
studies of hidden n-sources and/or low energy background necessary

13. ….. But not very good fits New Results from MUNU (hep-ex/0502)
T > 700 keV :
mn(ne) < 0.9 X mB (90% CL)
….. But not very good fits

14. TEXONO Research Program ………...

15. 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.
M. Deniz, M. Zeyrek
Middle East Technical University, Turkey
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.

16. Poineering Efforts : “Zero-Background Experiment” !
TEXONO Overview
Program:
Kuo-Sheng Reactor Neutrino Laboratory
※ reactor : high flux of low energy electron anti-neutrinos
※ oscillation expts.  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) ]

17. 

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

19. 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

20. 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]

21. Kuo Sheng Reactor Neutrino Laboratory : First Results

22. Reactor n @ Kuo-Sheng : TEXONO
simple compact all-solid design : HPGe (mass 1 kg) enclosed by active NaI/CsI anti-Compton, further by passive shieldings & cosmic veto
focus on keV range for high signal rate & robustness:
mn >> SM [decouple irreducible bkg  unknown sources make searches more conservative ]
T<<En  ds/dT depends on total fn flux but NOT spectral shape [well known : ~6 fission-n  ~ U capture-n per fission ]
selection: single-event after cosmic-veto, anti-Comp., PSD
Inner Target Volume

23. Cosmic Veto, Anti-Compton & PSD
Events correlated to Cosmic
No signal in Anti-Compton detectors
PSD : Events Selected

24. TEXONO data (4712/1250 hours ON/OFF) [PRL 90, 2003]
comparable bkg level to underground CDM experiment at keV :
~ 1 day-1keV-1kg-1 (cpd)
analysis threshold 12 keV
No excess of counts ON/OFF comparison
Limit:
mn(ne) < 1.3 X mB (90% CL)
more data/improvement to get to sensitivity range
mn(ne) 1.0 X mB

25. Reactor mn(ne) Sensitivities
Gn Sensitivities

26. Coverage in International Press

27. Combined Analysis [Grimus et al., …. ]
use all available information, incl. LMA global fit & error contour
take nM  only transition moments ni  nj
adopt mn direct limits from SK spectral shape & reactor expts
“Total” Magnetic Moment :
Reactor n:
n at SK:

28. KS Physics Program : Periods I & II & III
HPGe [1 kg] :
mn + Gn : x2 more data from PRL
improved background & analysis
study reactor ne flux & physics potentials
study possible nuclear transitions
e.g. 73Ge* decays by 2g’s separated by t1/2=4.6 ms
Study possible reactor axion searches
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

29. Reactor Neutrino Interaction Cross-Sections
On-Going Data Taking:
SM s(ne)
T > 2 MeV
R&D :
Coh. (nN)
T < 1 keV
Results & More Data:
mn(ne)
T ~ keV

30. Period II Installation – HPGe

31. Period-2 CsI(Tl) Array :
186 kg, 93 crystals
Goal : to make a measurement of neutrino-electron scattering cross-sections, i.e. sin2qw at q~MeV range

32. Single Crystal QL Vs QR (Raw Data)
Z = 0 cm
Z =40 cm
208Tl
40K
137Cs
Region of Interest for SM s(ne)

33. electron neutrino flux
Simulation of reactor
electron neutrino flux
Nuclear material
Fission products n
Structure material
Neutron sampling
Geometry description
Probability of EC decay
Electron neutrino flux
Physical model
n rich nuclei
－decay EC EC
Electron neutrino emission
n rich nuclei
－ decay
Stable isotope
even-even
Stable isotope
electron anti-neutrino emission

34. Exclusion Plot for ne Radiative Decays:

35. Looking for n-induced 73Ge*
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/after the transition
n-induced events signature: excess in the “ON+before” spectra

36. Reactor Axions Analysis with HPGe data
Like TEXONO HPGe
Reactor core has intense M1 transitions : e.g. 7Li, 91Y, 97Nb etc.
Signature : peak at transition energy at HPGe due to Primakoff conversion

37. “Ultra-Low-Energy” HPGe Prototype
mass 5 g ; can be constructed in multi-array form
threshold <100 eV after modest PSD (lowest achieved for bulk radiation detectors)
background measurement on-site Nov 03
study appl. in nN coherent scattering and Dark Matter searches

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

39. Sensitivity Plot for CDM-WIMP search with
1 kg ULEGe at 100 eV threshold ………

40. min. 700 m of rock overburden
TEXONO-KIMS Connections ………
KIMS: funded Dark Matter program with underground Y2L in Korea
TEXONO CsI(Tl) work & KS design adapted in KIMS’s set up at Y2L
Install LE-HPGe to Y2L for measurement 04/05  organized by THU team ; background below 1 keV, CDM searches
may evolve into a full-scale (1 kg) CDM experiment
may broaden framework in the future (regular joint meetings ; sharing of know-how ….)
Yangyang (襄陽) Lab (Y2L)
min. 700 m of rock overburden

41. Installations of ULEGe at Y2L in March 2005
Background studies
Feasibilities studies for CDM searches

42. Possibilities for Reactor q13 ………
IHEP’s q13 Proposal at Daya Bay near Hong Kong
 Compare Reactor close & at ~2 km to <1%
 More Powerful Reactor Complex
 More overburden possible from mountains
Tunnel Digging Cost Less in China
A High Profile (i.e. competitive subject)
Close contact with IHEP & Monitoring progresses & Exploring possibilities

43. R&D Projects Upgrading FADCs (+ FPGA etc. capabilities…..)
Explore New Detectors Scenarios (LEn, CDM …)
 other crystal scintillators (GSO …)
 ultra low energy HPGe [ O(100 eV) threshold ]
Feasibility Studies on CsI(Tl) for Dark Matter Searches
 Approved 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)
Completed
On-Going
Completed
Completed
On-Going
On-Going

44. 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 Results (PLB 02):
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. :
 kg CsI(Tl) for CDM
in S. Korea

45. TEXONO/KS FADC for SPring8/LEPS
40 MHz ; 12 bit ; 32 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 SPring8
TPC for 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)

46. Trace Radio-purity with AMS
Based at AMS 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 < g/g
 measure 40K~10-10 g/g in CsI (powder)
 develop techniques for K in liquid scintillator
Sensitivity goal : < g/g
Future :  87Rb …… [238U / 232Th series after Tandem upgrade]
====== NSF funded projected in China , led by CIAE =====

47. CIAE-AMS system

48. Sonoluminescence Project (AS,CIAE, NCU, NCCU….)
a frontier subject with possible surprises
new directions : to explore subjects we do not know
inter-disciplinary research
 a testing ground from HEP group future possibility
Table-top experiments, pursue-able in several labs
 balance the other big & long time-scale projects
 use HEP approaches
Focus :
 understand physics mechanism
 emissions of high energy radiations
SonoLum Pulse

49. Repeating ORNL experiment in preparation at CIAE
SL Typical Set-Up
SL Typical Cycle
Repeating ORNL experiment in preparation at CIAE

50. SonoLum Pulse

51. TEXONO STATUS TEXONO Collaboration:  Built-Up & 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/III DAQ  Improved HPGe Conf.
 196 kg CsI(Tl) [s(ne) …]
 LEGe: study potentials for scoh(nN)
Diversified R&D Program in parallel
Focus at AS :: mn  n-e S.  Coherent S.  SonoLum.
CIAE :: AMS  SonoLum.
THU :: CDM Search
Reaching Out
 Korea / Daya Bay Project (?) / Regional Framework

52. 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 (a modest) part of world neutrino physics community
Tremendous Pleasure & Pressure !