Transcript CosPa 2003
TEXONO Research Program on Low Energy
Neutrino and Astroparticle Physics
Recent Status of Neutrino Physics
TEXONO Collaboration : Overview
Kuo-Sheng(國聖) Reactor Neutrino Laboratory
※ Facilities
※ Research Topics
R&D Program
Henry T. Wong / 王子敬
Academia Sinica /中央研究院
@ Yong Pyong / 龍平
*
Taiwan EXperiement On NeutrinO
http://hepmail.phys.sinica.edu.tw/~texono/
Dm2 – : Summary
PDG 2000:
2002
SK atm. n
SNO solar n
KamLAND : picks LMA for solar n
K2K : Consistent Checks to atm. n
SK
Solar LMA Solution (before Sept 03)
+ SNO Salt Results …..
Neutrino Mass Structures :
Dm2
Normal Vs Inverted Hierachy ??
Quasi-Degenerate Vs Hierarchical ??
Atm. n
Solar n
※ absolute scale unknown
*
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
Initiate : Chang Chung-Yung 1996
Nanjing University, Nanjing, China
First Collab. Meeting/Official Start :
Y. An, D.Z. Liu, Q. Yue, Y.F. Zhu
October 1997
Tsing Hua University, Beijing, China
First Paper : October 1998
C.Y. Chang, G.C.C. Chang
KS Reactor Experiment Installation : June
University of Maryland, Maryland, U.S.A.
HISTORY
Co-Prinicipal Investigators
Ph.D. Students
2000
First Ph.D. : Liu Yan , July 2000
First Physics Data Taking : June 2001.
First Physics Results: Dec 2002.
Program:
TEXONO Overview
Kuo-Sheng Reactor Neutrino Laboratory
※ reactor : high flux of low energy electron anti-neutrinos
※ mn0 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 : n e n e ~ 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-)
sin2w 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:
P3+: Coh.
MM (ne)
(nN) <
1-100 keV
1 keV
Reactor as ne Source
Fission Material
Fission
Products
Mostly
rich in
neutrons
¯ Decay back to stable
valley
Anti-neutrino
Emisson
Neutrons
Captured
Captured
Structura
l
materials
of reactor
odd-odd
nuclei
Electron capture or +
decay ( neglected )
νe Emission
Tagging of 73Ge ½- 2g transitions:
Event-by-Event backgroundfree 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 :
238
232
U/ Th < 10
K < 10
40
-10
-12
g/g (equil.)
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
Venktesh Singh‘s Talk
Z =40 cm
208Tl
137Cs
40K
Region of Interest for SM s(ne)
“Ultra-Low-Energy” HPGe Prototype
mass 5 g ; can be constructed in multi-array form
threshold <100 eV after modest PSD
background measurement on-site Nov 03
study appl. in nN coherent scattering and Dark Matter searches
Hau-Bin Li & Qian Yue’s Talk
ULE-HPGe Prototype Results
PSD Cut
Threshold
~ 100 eV
Threshold < 100 eV
Signal Band
R&D Projects
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
(Feasibility Studies : TEXONO-CosPa Project)
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/ 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
SL Typical Set-Up
identify research topics ……..
SL Typical Cycle
SonoLum Pulse
Also ……….
Geographically possible for medium
baseline experiment for “13” :
Easy reach from city
Access to Plant established
Road tunnel at 2 km
100 m rock overburden
Contacts with International Team
IHEP’s 13 Proposal at Daya Bay near
Hong Kong (Li Jin’s talk)
TEXONO STATUS
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) …]
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 !