E status report Alexandre Camsonne Hall A Jefferson Laboratory Hall A collaboration meeting December 13 th 2007

Hall A collaboration meeting February 11, Outline He form factors Expected results Experimental setup He3/He4 Update Conclusion

Hall A collaboration meeting February 11, Few body form factors He 3 Form Factors He 4 Form Factors

Hall A collaboration meeting February 11, He3 form factor expected results

Hall A collaboration meeting February 11, He3 Form Factor expected results

Hall A collaboration meeting February 11, He4 Form Factor expected results

Hall A collaboration meeting February 11, Hall A E04018 Forward and backward measurement to separate the two form factors for He 3 High luminosity He 3 and He 4 measurement Use both HRS in coincidence to get elastic signal out of background background –Time of flight –Energy loss in scintillator –Kinematical correlation Experiment complete on July 2007 Analysis on going…

Experimental Details 20 cm long targets operated at 8K Beam current of up to 100 µA, corresponding to luminosity of nuclei/cm 2 /s Allowing cross section to be measured as small as cm 2 /sr Beam energy from 0.7 to 4.4 GeV, covering Q 2 from 1.5 (0.6) to 4 (5) GeV 2 for 3 He ( 4 He) with 3 angle settings for Rosenbluth separation on 3 He Scattered electron and recoiling nucleus detected in coincidence

Work in progress Next projects TOF Corrections Calorimeter Calibration 3-D VDC/Detector Track/Event Display Monte Carlo Improvements Computer Upgrade Cherenkov Gain Equalization corrections Detectors efficiencies

Hall A collaboration meeting February 11,

Hall A collaboration meeting February 11, Raw time of flight

Hall A collaboration meeting February 11, Corrected time of flight

Hall A collaboration meeting February 11, Corrected time of flight

Hall A collaboration meeting February 11, Conclusion Still setting up for full analysis New computers ordered Full production by January 2008 Preliminary results expected for summer 2008