A Large High Altitude Air Shower Observatory

LHAASO ProjectZhen Cao

Institute of High Energy Physics, China, Beijing 100049

TeVPA, SLAC,2009

Yangbajing Valley in Tibet

YBJ, Tibet4300m a.s.l.

Outline

• Scientific Perspectives

• Tentative design of a detector array

• Performance

• Prototyping

• Conclusion

Scientific Problems and Possible Solutions

• TeVγray observation has an opportunity of finding CR origin: 80+ sources discovered– 50+ galactic sources: γat high energy (>30TeV) is crucial

(high sensitivity and high energy resolution)

– All-sky survey forγsource population is necessary

(full duty cycle, wide FOV and sufficient sensitivity)

• PeV CR spectra of individual composition– Bridge between space/balloon borne measurements and g

round based UHECR measurements

• Searching for Dark Matter galactic sub-structures

？

Hadronic model

Leptonic model

A Tentative Design of A Complex Detector Array

Three major components• 1km2 complex array forγrays and CRs >30TeV

– 1 km2 scintillation detector array– 40k m2 μdetector array– 28 C-telescopes– 1k m2 burst detector

• 90k m2 water Cerenkov detector for γ>100GeV

• Two MagicII telescopes

Large High Altitude Air Shower Observatory

Charge Particle

Arrayμdetector

Array

Water CArray

LHAASO Project: γastronomy and origin of CR

Wide FOVC-Telescope

Array&

Core DetectorArray

Contribution of Magic Coll.

Water Cherenkov Detector

μdetector

Ground Charge Particle Detector

250mm

250m

m

20mm

1.2m

1m

scintillator PMT WS fiberThick Iron Case2.3cm

Wide FOVCherenkovtelescopes

Shower Core Detector YACYAC detector detector Pb(7r.l.)Pb(7r.l.)

Fe(1cm)Fe(1cm)PlasticPlastic 　　 scintiscinti..

Cost Free high energy

(1EeV)extension

Tower CT: 16

μ : 100x400m2

Side Trigger CT: 2x4

Re-Configuration

Performance

• 1km2 array for γdetection >50TeV

• MagicII @ Tibet site

• WCDA for source survey

• CR (30TeV ~ 1EeV): both knees &

absolute energy scale

Forγastronomy

ARGO

？

Resolution for light and heavy composition

μ-content, Xmax and HE (>30TeV) shower particles

Proton Iron

For Proton and Helium:

1.5 m spacing

Nb>100 , any 5

(> 30 GeV)

For Iron:

3.75m spacing

Nb>100 , any 21

( > 30 GeV)

The keys are to lower threshold, making connections with direct measurements & measure spectra up to 100PeV

A bridge between balloon measurements and ground base UHECR experimentcovering both “knees” with absolute energy scale

Dark Matter-rays from the sub-halos

Reed et al, MNRAS357,82(2004)

LHAASO sensitivityLHAASO sensitivity

-rays from smooth bkg-rays from smooth bkg

source

sun GC

ARGO sensitivity

Prototyping• R/D budget: ~$1M

• Detector unit prototype @ IHEP

On Site Prototype Exp.

• 1% of the final configuration of LHAASO

ARGO Hall

预先研究进展

• 1% 规模实验计划

From S. P. SWORDY, Space Science Reviews 99: 85–94, 2001.

CR Energy Spectrum

(160k events)

resolution < 10%With bias<3%Core resolution <1m

Conclusion

• a ground based large and complexγ/CR observatory at high altitude (4300m a.s.l.) within 5~10 years– Complementary to CTA in γastronomy– Unique for CR measurements at Knees– Perhaps useful for DM detection

Perspectives on γAstronomy

• Survey the whole sky for γsources above 100GeV (>90% of area is never surveyed at a sensitivity of 0.03ICrab)

• Investigate detailed energy spectra for galactic sources above 30TeV, cosmic ray sources are expected to be identified

• Detailed morphologic investigation of discovered sources for acceleration mechanism. (>30GeV)

Domestic Collaboration(13 inst.) • ARGO collaboration:

– APC of IHEP (detector design, project organization)– Tibet Univ. （ FPM ）– SW Jiaotong Univ. （ FPM: construction at high altitude)– Yunnan Univ. (PMT calib., optics) – Shandong Univ. (PMT calib.. Computing & Simulation)– Hebei Normal Univ. (Simulation)

• New collaborators– EPC of IHEP (KM2A electronics, DAQ)– USTC (WCDA electronics, trigger and PMT calib.) – PKU (computing, UHE CRs) – IAP (high Altitude Atmospheric Phys. )– CSSAR (Space weather monitoring and prediction)– NSMC (Space weather monitoring and prediction)– IMP (Biophys. & Environment )

• Communication Members (potential collaborators):– Tsinghua Univ. – Shanghai Jiaotong Univ.– Eastern Institute of Science and Technology – Nanking Univ.

International Collaboration • ARGO collaboration:

– Rome II Univ. （ RPC, Simulation, Slow Control ）– Lecce Univ. （ CRs, electronics)– Napeli Univ. (DAQ) – Torino Univ. (ECAL, GRBs)– …..

• Magic collaboration:– Max Planck Institute (Germany) (electr., Simulation, analysis)– Padova Univ. (Italy) (Telescope, optics)– IFAE (Spain) (Telescope, analysis)– …..

• Heidelberg Univ. (phys. Analysis)• Communication Members (future collaborators):

– HAWC Coll. (WCDA)

You are invited to Lhaaso at Lhasa!

Large High Altitude Air Shower Observatory