China’s Underground Scienceg&

Underground Laboratories Underground Laboratories

杨炳麟 (Bing-Lin Young) ( g g)

乌兰浩特专题讨论会

July 20-21, 2010

ContentsContentsContentsContents1. Introduction2 A i k i f th D B t 2. A quick review of the Daya Bay reactor

antineutrino θ13 experiment 3 Survey of world’s DULs and the science3. Survey of world s DULs and the science4. Dark Matter search and a dream DUL5 Worldwide DUL effort and international 5. Worldwide DUL effort and international

cooperation-Some preliminary thoughtsAcknowledgement: Adopted from talks given by

Herbert Steiner on Daya Bay, by Jian-Ping Chen on DUSL-China, and by Barry Barish on DUL science programs and international collaboration.

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I. Introduction 7/20/2010Bing-Lin Young

3

• Three technology platforms for researches in particle and astrophysics:p y▫ Accelerator based: energy frontier and intensity frontier; LHC

may be the limit of the energy frontier unless new accelerator energy technology is invented. LHC is preparing for intensity energy technology is invented. LHC is preparing for intensity frontier-luminosity: 1034 -> 1035 /cm2/s.

▫ Space based: discovery but indirect; earliest tools of particle physics began in the 1950s Now satellites provide a more physics began in the 1950s. Now satellites provide a more powerful space platform away from the atmospheric interference, e.g., indirect searches for dark matter, etc. U d d/ d t b d A f ti til▫ Underground/underwater based: A new frontier; versatile-covering many areas in science & engineering; long lasting research facilities, can be developed in stages, fast or slow,

di h f d k e.g., direct searches for dark matter, etc.

N t in s ill ti n xp im nts Neutrino oscillation experiments convincingly demonstrated DULs as a invaluable experimental platform for the invaluable experimental platform for the discovery and study of new physics.

DULs create an isolate but clean environment by cutting down cosmic ray backgrounds in observing rare events. It is generally the deeper the betteris generally the deeper the better.

The construction of a DUL is expensive and time consuming. an t m c n um ng.

Careful long range planning is necessary. 7/20/2010 Bing‐Lin Young 4

II. Quick review of the Daya Bay reactor ntin t in θ xp: Chin ’s fi st l s l antineutrino θ13 exp: Chinas first large scale

underground science effort Considerations of an experimental neutrino oscillation

program in China began in the early 2000s. At the 2005 Xiang Shan Workshop the Daya Bay θ13 At the 2005 Xiang Shan Workshop the Daya Bay θ13

experiment was discussed, inspired by the 2004 APS neutrino white paper.

Several challenges had to be met for a reactor neutrino gproject in China: to convince the physics community of its scientific importance; to get the needed financial support from the government; to establish partners for cost sharing and for collaborations on a wide range of cost sharing and for collaborations on a wide range of required works in physics, detector technology, and engineering.

After a rough start the present Daya Bay collaboration After a rough start, the present Daya Bay collaboration was formed in very early 2006.

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An excellent antineutrino source the Daya Bay nuclear power plant

1 GWth generates 2 × 1020 e per sec

the Daya Bay nuclear power plant enp

• 12th most powerful in the world (11.6 GW)• Top five most powerful by 2011 (17.4 GW)

Adj t t t i t t t t l t h d d • Adjacent to mountain, easy to construct tunnels to reach underground labs with sufficient overburden to suppress cosmic rays7/20/2010 6Bing‐Lin Young

Location of the Daya Bay Nuclear Power Plant 

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4 x 20 tons target mass at far site Daya Bay Layout

Far site1615 m from Ling Ao1985 m from DayaOverburden: 350 m

Ling Ao Near site~500 m from Ling AoOverburden: 112 m

Ling Ao-ll NPP(under construction) 22.9 GW in 2010

Construction

Water hall

Ling AoNPP, 22.9 GW

entranceFilling hall

Constructiontunnel

Daya Bay Near site363 m from Daya BayOverburden: 98 m

Total length: ~3100 mDaya Bay

NPP, 22.9 GW Horizontal TunnelTotal length 3200 m

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Baselines (m):TopographyQuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Excellent overburden to reduce cosmogenic background

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Status of Civil construction

fas of June 15, 2010

Various parts of detectors beingdetectors being assembled,  installed, or 

dTunnel entrance tested. First phase dry run successfully 

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conducded

Daya Bay: Goal and Approach• Utilize the Daya Bay nuclear power complex to:

determine sin2213 with a sensitivity of 0.01yby measuring deficit in e rate and spectral distortion.

1

km)

This is an 1%

0.995

ed fr

om 0

.3

sin2213 = 0.01This is an 1% accuracyExperiment which is very

0.99

km/P

redi

cte y

challenging. Have to design & build the d d

0.9850 1 2 3 4 5 6 7 8R

atio

(1.8

k

2 3 4 5 6 7 8 9 10

detectors minizedall possible backgrounds.

Prompt Energy (MeV) energy (MeV)7/20/2010 11Bing‐Lin Young

Sensitivity of Daya BayQuickTime™ and a

TIFF (Uncompressed) decompressorare needed to see this picture.

sin2213 < 0.01 @ 90% CL in 3 years of data taking13 y g

%CL

)

0.05

0.04

2 2 1

3(9

0%

0.38% relative detector syst. uncertaintym2

31 = 2.5 103 eV2

0.03

0.02ti

vity

in s

in

0 1 2 3 4 5

0.01

0.

Sens

it

Number of years of data taking

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Expected Antineutrino RatesExpected Antineutrino Rates

Sit R t

(Per Day per Module)

Site RateDYB 840LA 740Far 90Far 90

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Daya Bay Antineutrino Detector

• 8 “identical”, 3-zone detectors

calibrationcalibration system

e + p e+ + ne p

acrylic tanks

steel tankGd-doped

liquid scintillator

target mass: 20t per detectordetector mass: ~ 110tphotosensors: 192 PMTs

acrylic tanksphotomultipliersliquid

scintillator

mineral oilphotosensors: 192 PMTsenergy resolution: 12%/�E

III. Present status of DyBRANECi il C i

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Civil Construction

Surface Assembly BldgEntrance

Control RoomInside tunnel7/20/2010 15Bing‐Lin Young

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Tunnel Construction

Pool Excavation in DBY Hall ‐ Aug 09 Main Tunnels Join ‐ June 09

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Detector AssemblyQuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

4-m vessel in the U.S.Stainless steel tank in China

3-m acrylic vessel in Taiwan

SS Tank delivery Delivery of 4m AV Stainless steel tank in SAB7/20/2010 17Bing‐Lin Young

AD AssemblyQuickTime™ and a

TIFF (Uncompressed) decompressorare needed to see this picture.

AD Assembly

Civil Construction of Daya Bay Reactor y yNeutrino Experiment

Changgen Yang

2010/07/16

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Overall ScheduleOverall Schedule• 2003-2007: Proposal, R&D, engineering design etc.• October 2007: Ground Breaking for tunnel and labs October 2007: Ground Breaking for tunnel and labs. • March 2009: Surface Assembly Building occupancy July 2010

D B h ll l t d t b d b t Daya Bay near hall completed to be approved by government successful dry run Ling Ao near hall not far from completion Far hall excavation in progress Far hall excavation in progress

• Spring 2011: Daya Bay Near Hall ready for data taking • Fall 2012: Full operation of all near and far halls ready

for data taking for data taking

Full sensitivity is expected to be reached in three ’ d t t ki years’ data taking.

III. Survey of world’s DUL and the science

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)( ssneutrinole

Earth LabELabE

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Some of the reachable fundamental ti i ti l d t h iquestions in particle and astrophysics

BarryBarish

Requires 

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qvery DULs

Depth of world’s know DULs

8000 ftOOr

2440 mOf rockOr

6600 MWE

But none of the existing USL has reached the 

desired 2500

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2500 m

• Does not list Canfranc, near Zaragoza, spainwhich houses the exp NANSI

P l f h i Presently one of the most active programs for DUL is the direct search for dark matter.

Worldwide there are about 20 experiments Worldwide there are about 20 experiments either completed, running, or being constructed. constructed.

To find out what is dark matter is crucial for fundamental science: particle physics, and astrophysics/cosmology.

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)( incompleteList

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中国锦屏极深地下实验室 (CJPL) China JinPing deep underground Laboratory,

d hmanaged by Tsinghua University

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国际上重要地下实验室比较(单位:meters of rocks)

700m

600

Y2L韩国

800mCanfranc西班牙

1100m600mSoudan美国

1000mKamioka日本

1100mBoulby英国 1400m

INO印度

1400mLNGS意大利

1600m 1500m印度 1600m

Baksan俄罗斯

DUSEL美国

2300m2000m

1700mModane法国

2500m中国锦屏

隧道

矿井 2000mSNO加拿大

法国矿井

Deep Underground Lab极深地下实验室

地下实验室建设规划

展示空间

主实验厅展示长廊

展示空间

世界上条件最好,可以成为最具潜主实验厅 可以成为最具潜力的地下实验室！

CJPL内部空间规划

•2010年4月，地下实验室土建工程竣工仪式

•2010年6月，地下实验室配套设施建设工程完工

Schedule for completion and data taking?

V. DULs science, worldwide effort, and international cooperation on - some initial thoughtscooperation on - some initial thoughts

BarryBarry Barish

From anFrom an earlier talk of  his.

Some  challenges may have been 

partially addressed. 

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Some more basic questionsSome more basic questions

From Barry Barish

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From Barry Barish

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From Barry Barish

PaNAGIC:

The Particle and Nuclear Astrophysics Astrophysics

and Gravitational Committee

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Some more thoughts China has expanding programs in all three technology China has expanding programs in all three technology

platforms, a bright spot in the generally shrinking support for basic research elsewhere worldwide support for basic research elsewhere worldwide, especially in developed countries.

H l thi l t i Chi i li ht f How long can this last in China, in light of many economic uncertainties and the effects of

th i l b l i l t d t th t anthropogenic global warming related to the present mode of economic and industrial expansions?

h ld h b l f h h Should there be a national priority set after a thorough examination of China’s goal, potential, and

h b l7/20/2010Bing-Lin Young35

achievability?

Daya Bay offers a good example and valuable l f i t ti l ll b ti lessons for international collaboration.

For CJPDUL: What is the ambition of the Chinese community of basic science and Chinese community of basic science and engineering? Are there any advantages for labs at different depth? Is one depth enough?at different depth? Is one depth enough?

In light of competing government agencies which support various basic science programs should support various basic science programs should there be a superagency to oversee the development for large and long range national programs with international impact, having the ability to bypass turf fight (not a Chinese phen men n) am n equal a encies?phenomenon) among equal agencies?

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As the earlier ones of the series lwe anticipate a stimulating 

conference starting todayconference starting today.

谢谢

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