1、9/14/2007,TAUP 2007, Sendai,1,The Daya Bay Reactor Neutrino Experiment,Shaomin Chen (for the Daya Bay collaboration)Tsinghua University, Beijing, ChinaTAUP 2007, Sendai, Japan,9/14/2007,TAUP 2007, Sendai,2,CP violation in lepton sector,13 is the gateway of CP violation in lepton sector!,Three-neutri
2、no oscillation,To incorporate CP violation into the three-light-neutrino model,Pontecorvo-Maki-Nakagawa-Sakata Matrix,CP violation parameters: Dirac phase , Majorana phases 1, 2,9/14/2007,TAUP 2007, Sendai,3,Theoretical predictions for 13,A precise 13 measurement is helpful in understanding the phys
3、ics beyond the Standard Model.,9/14/2007,TAUP 2007, Sendai,4,How to measure 13?,Disappearance searches at reactors: Appearance searches at accelerators:,Reactor experiments provide a clean environment to measure q13.Accelerator experiments give access to both q13 and d values.,9/14/2007,TAUP 2007, S
4、endai,5,Current knowledge on 13,Direct search (PRD 62, 072002),Global fit (hep-ph/0506083),A small q13(e.g. sin22q13 (99.5 0.25) %,9/14/2007,TAUP 2007, Sendai,18,Estimated efficiencies,Neutron detection efficiency is a product of 85% Gd fraction and 93% energy cut.,9/14/2007,TAUP 2007, Sendai,19,Sum
5、mary of uncertainties,9/14/2007,TAUP 2007, Sendai,20,Goal to be reached at Daya Bay,The sensitivity of 0.01 for sin2213 will be reached in 2013.,9/14/2007,TAUP 2007, Sendai,21,This needs a team effort!,North America (14)BNL, Caltech, LBNL, Iowa state Univ.Illinois Inst. Tech., Princeton, RPI, UC-Ber
6、keley, UCLA, Univ. of Houston, Univ. of Wisconsin, Virginia Tech.,Univ. of Illinois-Urbana-Champaign, George Mason Univ.,Asia (18)IHEP, CIAE,Tsinghua Univ.Zhongshan Univ.,Nankai Univ.Beijing Normal Univ., Nanjing Univ.Chengdu Univ. Tech., Shandong Univ.Shenzhen Univ., Hong Kong Univ.USTC,Chinese Hon
7、g Kong Univ.Taiwan Univ., Chiao Tung Univ.,National United Univ.,CGNPG,Dongguan Univ. Tech.,Europe (3)JINR, Dubna, RussiaKurchatov Institute, RussiaCharles University, Czech Republic, 160 collaborators,9/14/2007,TAUP 2007, Sendai,22,Recommendations,第250次香山科学会议简报 (2005)Meeting brief for the 250th Xia
8、ngshan Scientific Meeting2中微子混合角13是自然界的基本参数之一，是一个急需解决的关键问题。Neutrino mixing angle 13 is one of the fundamental parameters in nature,a key issue to be resolved. 3条件已经基本成熟，而且实验得到了大亚湾核电站有关方面的大力支持。准备充分，完全有能力和实力完成这项实验。have mature technology and get strong support from Daya Bay Nuclear Power Plant. get pre
9、parations well done and have capability and strength to complete this experiment. 4确定13在国际上竞争激烈，项目在年内立项是赢得国际竞争的关键。International competition in determining 13 is very vigorous,getting the project approved promptly is a key to win the competition. ,This is an usual way to initiate a giant research pro
10、ject in China.,9/14/2007,TAUP 2007, Sendai,23,Roadmap,Passed DOE scientific review Oct. 2006CDR released (hep-ex/0701029) Jan. 2007 Passed US CD-1 review April 2007Passed final nuclear safety review in China April 2007Received funding from Chinese agencies April 2007TDR to PAP released Sept. 2007Gro
11、und breaking ceremony Oct. 2007Anticipate US CD-2/3a review Nov. 2007Deployment of the first detector July 2009Data taking with final configuration Sept. 2010,9/14/2007,TAUP 2007, Sendai,24,Summary,An ultimate sensitivity of 0.01 for sin2213 is designed to be reached at the Daya Bay experiment.Detec
12、tor design is close to complete. Received commitment from Chinese funding agencies.US CD-2/3a Physics Review scheduled for Nov. 2007.Civil construction will start from Oct. 2007, detectors will be deployed in 2009, and full operation expected in 2010.,9/14/2007,TAUP 2007, Sendai,25,And more,We alrea
13、dy know GuangDong province is a place forproviding one of the most delicious foods and the cheapest “Made in China” products in the world. We are anticipating it will also be an excellent place for us to have the most precise “Made in China” 13 .,Thank you!,9/14/2007,TAUP 2007, Sendai,26,Back-up sli
14、des,9/14/2007,TAUP 2007, Sendai,27,Reactor neutrino spectrum,Reactor neutrino rate and spectrum depends on:The fission isotopes and their fission rate, uncorrelated 1-2%Fission rate depends on thermal power, uncorrelated 1%Energy spectrum of weak decays of fission isotopes, correlated 1%Three ways t
15、o obtain reactor neutrino spectrum:Direct measurement at near siteFirst principle calculationSum up neutrino spectra of 235U, 239Pu, 241Pu(from measurement) and 238U(from calculation, 1%)They all agree well within 3%,9/14/2007,TAUP 2007, Sendai,28,Calibrating Energy Cuts,Automated deployed radioacti
16、ve sources to calibrate the detector energy and position response within the entire range. 68Ge (0 KE e+ = 20.511 MeV s) 60Co (2.506 MeV s) 238Pu-13C (6.13 MeV s, 8 MeV n-capture),9/14/2007,TAUP 2007, Sendai,29,Estimated event rates,The total event rate in each site is less than 3.5 kHz and istheref
17、ore affordable in the readout-every-hit scheme.,9/14/2007,TAUP 2007, Sendai,30,FEE and trigger system,9/14/2007,TAUP 2007, Sendai,31,Sources of systematics,Detector-related,Reactor-related,9/14/2007,TAUP 2007, Sendai,32,Reactor-related uncertainties,Assuming 30 cm precision in core position,9/14/2007,TAUP 2007, Sendai,33,Background-related errors,Uncorrelated backgrounds: U/Th/K/Rn/neutron Single gamma rate 0.9MeV 50HzSingle neutron rate 1000/dayCorrelated backgrounds: Fast Neutrons: double coincidence 8He/9Li: neutron emitting decays,
