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Summary of the workshop on Future Low-Energy Neutrino Experiments TUM, Munich, October 9-11, 2003. Thierry Lasserre CEA/Saclay, CERN, 20/11/2003. e. e,,. One nuclear plant & two detectors. D 1 = 0.1-1 km. D 2 = 1-3 km. Nuclear reactor 1,2 core(s) ON/OFF : ok
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Summary of the workshop on Future Low-Energy Neutrino Experiments TUM, Munich, October 9-11, 2003 Thierry Lasserre CEA/Saclay, CERN, 20/11/2003
e e,, One nuclear plant & two detectors D1 = 0.1-1 km D2 = 1-3 km Nuclear reactor 1,2 core(s) ON/OFF : ok 4 cores ON/OFF : no ! Near detector 5-50 tons > 50 mwe Far detector 5-50 tons > 300 mwe • Isotrope e flux (uranium & plutonium fission fragments) • Detection tag : e + p e+ + n, <E>~ 4 MeV, Threshold ~1.8 MeV • Disappearance experiment: suppression+shape distortion between the 2 detectors • 2 IDENTICAL detectors (CHOOZ, KamLAND, BOREXINO/CTF type) • Minimise the uncertainties on reactor flux & spectrum (2 % in CHOOZ) • Cancel cross section uncertainties • Challenge: relative normalisation between the two detectors < 1% !
Groups involved in discussions • US : • Columbia University • Argonne National Laboratory • Berkeley Laboratory • The University of Chicago • The University of Alabama • Caltech • Stanford University • etc … • France : • PCC, Collège de France & APC • (Chooz, LENS, Borexino) • CEA/Saclay • (LENS) • Germany : • MPI fuer Kernphysik, Heidelberg • (Borexino, LENS Gd scintillator) • TUM, Munich • (Borexino) • Tubingen University • (Borexino) • Italy : • INFN Bologna • Japan : • Tokyo Metropolitan University • Tohoku University • Russia : • Kurchatov Institute sorry for the groups I have omitted …
X 2 Double CHOOZ 10-15 t ! Detector size scale Reactor/13 Example ~20 t ( 5 50 t) CHOOZ 5 t Borexino 300 t KamLAND 1000 t
90% C.L. sensitivity if sin2(213)=0 @m2=2.0 10-3 eV2 σbkg σbkg σbkg JHF 1% Huber, Lindner, Schwetz & Winter: hep-ph/0303232 G. Men tion & T. L. 0.1% reactor 1 (2 RNU) reactor 2 (40 RNU) RNU = Reactor Neutrino Unit : 1 RNU = 1031 free H GWth year • Reactor1 (0.5 km, 2.3 km): ~13 tonsPXE x 10 GW x 3 years sin2(213)<~0.02, 90% C.L • Reactor2 (0.5 km, 2.3 km): ~270 tonsPXE x 10 GW x 3 years sin2(213)<~0.01, 90% C.L
Forthcoming LBL & sin2(213) CHOOZ-I 90% C.L Huber, Lindner, Schwetz & Winter (Theory group, TUM)
Next generation LBL & sin2(213) CHOOZ-I 90% C.L Huber, Lindner, Schwetz & Winter, (Theory Group, TUM)
Which site for the experiment ? Penly Chooz Cruas Byron Kashiwasaki Krasnoyarsk Diablo Canyon Taiwan Angra One reactor complex Two underground cavities @0.1-1 km & ~1-2 km
Which site for the experiment … CHOOZ Kashiwasaki Diablo Canyon
The Diablo Canyon site (US) 600-800 mwe • Close to San Francisco (500 km), California. Leader Group: LBNL • Two cores (2 x 3.1 GWth) • 3 detectors : D1~300m , D2 ~ 0.8 – 1 km , D3 ~ 2 – 3 km • Horizontal tunnel >1.5 km with 300 800 mwe overburden • Status: negotiation with the power plant underway (permit, safety , ecology …) Partial approval from PG&E to proceed with geological studies • Tunnel + labs + 2 movable detectors (50-100 tons) to be constructed simultaneously • Data taking end 2007 ? Cost ~ 50 M$ • sin2(213)<0.01-0.02 @90% C.L
The Kashiwasaki site (Japan) Kashiwasaki power plant: 24.3 GWth 7 cores 2 near detectors needed ! Leading group: Tohoku Univ. (Suekane_san & Inoue_san)
Scheme of one shaft The Kashiwasaki site (Japan) • Kashiwasaki power plant : 24.3 GWth • 7 cores 2 near detectors needed ! • D1~300-400 m , D2 = 1.3 km • 3 identical detector of ~8 tons 3 shafts (12 M$, 15 months) • Near detectors @100 mwe • Far detectors @500 mwe • Data taking ~2007-2008 – Cost <20 M$ Sensitivity (3 years): sin2(213)<0.026 @90% C.L
The Chooz site, Ardennes, France … Double-CH1313Z …
The Chooz site Near site: D~100-200 m, overburden 50-80 mwe Far site: D~1.1 km, overburden 300 mwe [former experimental hall] 2x11.5 tons, D1=100-200m, D2=1050m. Sensitivity: 3 years sin2(213) < ~0.03
CHOOZ-Far detector (12.7m3 fiducial, preliminary) 3.5 m CHOOZ-I pit 7 m
CHOOZ-Near 250 m 125 m A few locations under study, but enough space in any case
CHOOZ-Near new Laboratory ~10-15 m Dense material ~5- 15 m Other possibility: bloc of concrete (d~2.4) piled up !
Status of the discussions with EDF • CHOOZ site has been secured. -Strong support for the CHOOZ nuclear plant • Far site: 1.1 km & 300 mwe -Existing laboratory -Available (7x7 m tank of CHOOZ-I) • Near site: 100-200 m -Underground detector + man-made overburden -Feasibility confirmed by the power plant staff -50 to 80 mwe required -Civil engineering study will start soon (done & financed by EDF )
The experimental challenge Relative error between Near/Far detector < 0.8% seems possible [still under study]
Sensitivity to sin2(213) sin2(213) @90% C.L σbkg: [near] = 1% [far] = 0.5% σbkg: [near] = 1% [far] = 1% σbkg: [near] = 2% [far] = 1% @m2atm=2.0 10-3 eV2 years 1 0.75 2 1.5 3 2.25 4 (pure PXE) 3.0 (PXE/PC + mineral oil) 1 #DNear 0.1 km #NumberOfFreeProtonsNear 1.8944e+29 (11.5 tons PXE) #DFar 1.05 km #NumberOfFreeProtonsFar 3.7888e+29 (11.5 tons PXE) #Global normalisation Fit is [ON ] with an error of 2% #Relative normalisation Fit of Near/Far Detector is [ON ] with an error of 0.06% #Shape Error Fit is [ON ] with an error of 2%
Summary & outlook @Double-CHOOZ • Support for the EDF power company to do a 2nd experiment @CHOOZ Reactor potential @CHOOZ: sin2(213)<~0.03, 90% C.L. (m2 = 2.0 10-3 eV2) Current limint: CHOOZ : sin2(213)<0.2 discovery potential ! • Technology / design well known (Chooz-I, Borexino, KamLAND, …) few R&D needed : Gd loading (stability) + material compatibility R&D in Saclay : material compatibility + mechanical constraint + scint. test • Case under study: French target vessels & German scintillator (MPIK) • Experiment cost, Double-CHOOZ case: 2 x ~15 tons, cost detectors <~10 Meuros. (+ Civil engineering) • Our Goal @CHOOZ: Construction starts in 2005 (+ civil engineering ) Start data taking in 2007-2008 year 2004 2005 2006 2007 2008 2009 2003 Site Prop. design Construction ? Construction ? Data taking < sin2(213) < 0.025-003 < sin2(213) < ~0.04