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Stato del calorimetro elettromagnetico. Nuove misure a TERAS (maggio) TEST beam al PSI (ottobre – novembre-dicembre) Lxe facility Criostato. TERAS g Beam Line. Compton Spectrum (E g -Ec/2) 2 +(Ec/2) 2. Electron beam Energy: 764MeV Energy spread: 0.48%(sigma)
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Stato del calorimetro elettromagnetico • Nuove misure a TERAS (maggio) • TEST beam al PSI (ottobre – novembre-dicembre) • Lxe facility • Criostato
TERAS g Beam Line • Compton Spectrum • (Eg-Ec/2)2+(Ec/2)2 • Electron beam • Energy: 764MeV • Energy spread: 0.48%(sigma) • Divergence: <0.1mrad(sigma) • Beam size: 1.6mm(sigma) • Laser photon • Energy: 1.17e-6x4 eV (for 40MeV) • Energy spread: 2x10-5 (FWHM) • Divergence: unknown • Beam size: unknown Collimator size
LP operato con Xenon purificato g Data MC simulation D D Short labs Previous Test D= • D: depth parameter D: 20~100 0~25cm D Long labs This Test D D
Energy Spectrum Fitting • For understanding simply… • Suppose Response function is an asymmetric Gaussian • Principle… Compton Spectrum Response function Eg Npe s left Convolution of Compton Spectrum Response Function s right
Energy Spectrum Fitting cont’d • Require D(depth parameter)>45 • ~34% of events in the range of 40MeV+/-4MeV are discarded by this requirement • Suppose Compton Spectrum around the edge (E-Ec/2)2+Ec2/4 • Detector Response Function • Gaussian with Exponential tail f(x) = Nexp{t/s2(t/2-(x-x0)}, x<x0+t Nexp{-1/2((x-x0)/s)2}, x>x0+t • Convolution • Integration +/- 5s • Fitting is done in two steps • Determine the edge position • Fix the edge in the 2nd fitting for determining the other prams Detection efficiency (estimated by MC) : 74% within +/- 4% energy cut at 52.8 MeV (cf. Progress Report Jul 02) (16% of events are lost due to interaction with material in front of the active volume) 26%
Energy Resolution vs. Depth Parameter • For g incident at the detector center • D > 35, 45, 55….85 • Resolution: < 2% in sigma except shallow events (D<45). D Number of Photoelectrons
LP al PSI (meta’ agosto): test in ottobre/novembre con fotoni monocromatici
The elementary process - (essentially) at rest captured on protons: - p 0 n - p n 0 Photon spectrum 129 MeV 54.9 82.9
-- beam C T A Mod Experimental configuration TARGET? • Rate • Background • Thin/small (angle/X0) • Handling NaI Previous use • GH2 (Panofsky….) • LH2 (PIBETA) • CH2 (MEGA, prec.misure) • LiH (e at SIN) Coincidence: C & !A & NaI (Offline: & LXe) LXe
Misure del 1999 8%FWHM • D=100 cm • 10 x 10 window • 9.5 hours • 60 cm (NaI) 75 cm (CsI) • 11 x 13 window
Criostato • Necessita’ di rivedere il disegno (appoggio esterno ) • Selezione materiale finestra di ingresso • Simulazioni nuovo progetto • Contatto con Ditte produttrici il prima possibile
Photon Detector schedule 2002 2003 2004 2005 Large Prototype Beam Test Beam Test Engineering runs Vessel Design Manufactoring Assembly & Test PMT Delivery + Testing Assembly Test Refrigerator Manufactoring Assembly Liq. Purification Design Manufactoring Assembly Test Milestone