Post on 28-Dec-2015
Low Energy Neutrino Physics at the Kuo-Sheng Nuclear Power Plant
Overview of TEXONO Collaboration
Kuo-Sheng Reactor Neutrino Laboratory
Results on Neutrino Magnetic Moments
R&D projects towards Neutrino-Nucleus Coherent Scattering
Survey of Other Research Program (KS and non-KS based)
Summary & OutlookHenry T. Wong / 王子敬
Academia Sinica / 中央研究院
@
TEXONO Collaboration
Collaboration : Taiwan (AS, INER, KSNPS, NTU) ; China (IHEP, CIAE, THU, NJU) ; Turkey (METU) ; USA (UMD)
Program: Low Energy Neutrino & Astroparticle Physics
Kuo-Sheng (KS) Reactor Neutrino Laboratory reactor : high flux of low energy electron anti-neutrinos oscillation expts. m0 anomalous properties & intera
ctions physics full of surprises , need intense -source
※ study/constraint new regime wherever experimentally accessible
※ explore possible new detection channels Diversified R&D Projects
Taiwan EXperiment On NeutrinO
Poineering Efforts : “Zero-Background Experiment” ! KS Expt: 1st large-scale particle physics experiment in Taiwan
TEXONO Coll. : 1st big research Coll. % Taiwan & China
Kuo-Sheng Nuclear Power Plant
KS NPS-II : 2 cores 2.9 GW
KS Lab: 28 m from core#1
Kuo Sheng Reactor Neutrino Laboratory
Front Gate
Configuration: Modest yet Unique
Flexible Design: Allows different detectors conf. for different physics
Inner Target Volume
Front View (cosmic vetos, shieldings, control room …..)
R&D : Coh. (N)
T < 1 keV Results & More Data:
(e)
T ~ 1-100 keV
On-Going Data Taking & Analysis SM (e)
T > 2 MeV
Reactor Neutrino Interaction Cross-Sections
massquality Detector requirements
KS Expt: Period I,II,III Detectors
FADC Readout
[16 ch., 20 MHz, 8 bit]
ULB-HPGe [1 kg] CsI(Tl) Array
Multi-Disks Array [600 Gb]
fundamental neutrino properties & interactions ; necessary consequences of neutrino masses/mixings ; in principle can differentiate Dirac/Majorana neutrinos (D/M)
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, esp. @ low energy explore roles of neutrinos in astrophysics
Neutrino Electromagnetic Properties : Magnetic Moments
e.g.
requires m0
Magnetic Moment Searches @ KS
simple compact all-solid design : HPGe (mass 1 kg) enclosed by active NaI/CsI anti-Compton, further by passive shieldings & cosmic veto
selection: single-event after cosmic-veto, anti-Comp., PSD
TEXONO data (4712/1250 hours ON/OFF) [PRL 90, 2003] background comparable to under
ground CDM experiment : ~ 1 day-1keV-1kg-1 (cpd)
DAQ threshold 5 keV analysis threshold 12 keV
Combined Analysis with all Information :
Denote
Limit:e) < 1.0 X 10-10 B (90% CL)
X 3 data volume : expect sensitivity range
e) 8 X 10-11 B
supression ; spectracut g ; SM
; cutsafter before, 1,2 ; OFFf ; ONg
1
2
1
22
1
g
g
f
g
fg
1contour
ON-OFF only
Search of at low energy high signal rate & robustness:
>>SM [ decouple irreducible bkg unknown sources ] T << E d/dT depends on total flux but NOT spectral
shape [ flux well known : ~6 fission- ~1.2 238U capture-per fission ]
22
11)(2
ETmedT
de
Couplings : Neutrino Radiative Decays
a fundamental neutrino interaction never been experimentally-observed
~N2 applicable at E<50 MeV where q2r2<1 a sensitive test to Stardard Model an important interaction/energy loss channel in astrophysics m
edia a promising new detection channel for neutrinos, without strict
lower bound on E & the channel for WIMP direct detection ! involves new energy range at low energy, many experimental c
hallenges & much room to look for scientific surprises
Standard Model Cross-Sections:
Neutrino-Nucleus Coherent Scattering
“Ultra-Low-Energy” HPGe Prototype
ULEGe – developed for soft X-rays detection ; easy & inexpensive & robust operation
Prototype : (I) 5 g ; (II) 4 X 5 g ; (III) 10 g ; (IV) segmented 20 g
threshold <100 eV after modest PSD [lowest achieved for bulk radiation detectors]
study feasibilities for 1-kg-ish detector for coherent scattering and Dark Matter searches [ search a by-product ]
5 g
4 X 5 g
ULE-HPGe Prototype Results
※ threshold ~100 eV , calibration by linear extrapolation from 1-6 keV
※ PSD possible to suppress noise edge
Threshold ~ 100 eV
Yangyang ( 襄陽 ) Lab (Y2L)min. 700 m of rock overburden
Install 5 g ULB-ULEGe at Y2L on January 2005
Study background and feasibility for CDM searches
may evolve into a full-scale (1 kg) CDM experiment
TEXONO KIMS @ Y2L
Sensitivity Plot for CDM-WIMP search with
1 kg ULEGe at 100 eV threshold ………
Background Measurements & Comparisons
Similar background at KS & Y2L Apparent difference between 5 g & 1 kg due to scaling with s
urface area instead, reproduced in simulations i.e. background can be ~ O(1 cpd) at > 1 keV range for 1 kg ULE
Ge in compact array form New detection channel in Unexplored kinematic regime :
“don’t know what to expect and what are expected”
(keV)
First-Ever Low Background Data down to 100 eV ……. !
….. More data taking & analysis underway
CsI(Tl) Array (~200 kg) : e)
Z =40 cm
Single Crystal QL Vs QR
(Raw Data)
Region of Interest for SM e)
Z = 0 cm
208Tl
40K 137Cs
Data analysis under way……..
Electron Neutrinos @ Reactor (PRD 72, 2005)
Nuclear material
Fission products
n rich nuclei
n rich nuclei
Stable isotopeStable isotope
Structure materialn
decay
decay
EC EC
even-even
Electron neutrino emission
electron anti-neutrino
emission
Evaluate e flux at standard reactors
Derive limits on and for e
Explore e flux enhancement in loaded reactor (e.g. with Cr)
Study Potential applications : eNCC cross-section meas
urements, 13 Pu-production monitoring
Tagging of 73Ge ½- 2 transitions
Event-by-Event background-free tag with PSD
To do : Reactor ON/OFF analysis on the system ~1 s before/after the transition
-induced events signature: excess in the “ON+before” spectra
Looking for -induced 73Ge*
Reactor Axions Analysis with HPGe data
Reactor core has intense M1 transitions : e.g. 7
Li, 91Y, 97Nb etc. Signature : peak at tra
nsition energy at HPGe due to Primakoff conversion
Like TEXONO HPGe
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
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.
Mixed signal FADC Adapter Board
TEXONO/KS FADC for SPring8/LEPS
(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 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)
develop techniques for K in liquid scintillator
Sensitivity goal : < 10-16 g/g
Future : 87Rb …… [238U / 232Th series after Tandem upgrade]
Sonoluminescence Project
SonoLum Pulse
a frontier subject with possible surprises
new directions : to explore subjects we do not know
inter-disciplinary research
new research style and experience enriching
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
TEXONO Collaboration: Built-Up from Scratch & Maturing Kuo-Sheng Neutrino Lab.: Established & Operational Modular & Flexible Design Physics Data Taking since June 01 ※ Unique HPGe Low Energy Data ※ Bkg Level ~ Underground CDM ExptResults published on & reactor e
Summary & Outlook
Diversified Program in Parallel Main Thrust on ~200 kg CsI(Tl) [(e) …] ULEGe: for coh(N) + CDM Present Focus of Collaborating Groups: AS :: -e S. Coherent S. SonoLu
m.CIAE :: AMS SonoLum.
THU :: CDM SearchReaching Out Y2L @ Korea / Daya Bay Project (?) / Regional Framework
TEXONO is a (modest) part of world neutrino physics community
Tremendous Pleasure & Pressure !