survey of leps at tpc wen-chen chang. charge the flux, energies, and polarizations of the beams that...
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Survey of LEPS at TPC
Wen-Chen Chang
Charge
• the flux, energies, and polarizations of the beams that can produce at TPS. Since it will not be tunable, how easy it will be for you change your laser system to get different beam energy?
• the cost for the detector, targets (including polarized ones), laser systems, and electronics,
• how can you compete with MAIMI II, Jlab, and SPring8 as JW asked?
• currently planned exps. on Roper resonance.
Photon Flux
Laser and electron
Laser &
Wavelength
Output Power
Repetition
Rate
Pulse
length
Electron Current & Energy
Photon Flux & Emax
SPring-8 Paladin
355 nm
8W 80MHz 5ps 100mA
8 GeV
700 KHz
2.5 GeV
TPS INDIGO-DUV
193 nm2mW 5KHz 15ns 300mA
3.3 GeV
0.7 KHz
0.8 GeV
TPS AVAI
266 nm3W 100KHz 25ns 300mA
3.3 GeV
1.2 MHz
0.6 GeV
Cost Estimate
• Laser: $200K USD / per unit• Target: un-polarized LH2/LD2 target $20K
/ Polarized HD target $1M• Detector: crystal ball with 4 coverage, m
y guess is $300K – 500K • Electronics: $500K• In total:
– Unpolarized: $1.2 M– Polarized: $2.2 M
LEPS2
• Higher photon flux: 10MHz
• Detectors with large acceptance: move E949 detector system from BNL to Spring-8
• Higher photon energy: 3.5 GeV
MAMIC
Experimental set-up
Tagged photon beam Mainz: m E 800 MeV (Photon 10**8 Hz)
Bonn: 0.6 GeV E 2.9 GeV
Circularly polarized photons
Bremsstrahlung of linearly polarized electrons
Longitudinally polarized Protons/Deuterons
Frozen spin butanol target (Bonn, Bochum, Nagoya)
Mainz: DAPHNE detector (Pavia, Saclay) + forward angle detectors (Pavia, Mainz, Tübingen, Gent)
Bonn: GDH Detector (Erlangen, Tübingen, Gent)
Large acceptance hadron detectors
http://theory.gsi.de/hirschegg/2004/Proceedings/Beck_134.93.132.231_Ftmphirschegghirschegg1example.pdf