1. E04-018 status report Alexandre Camsonne Hall A Jefferson Laboratory Hall A collaboration meeting December 13 th 2007

2. Hall A collaboration meeting February 11, 2014 2 Outline He form factors Expected results Experimental setup He3/He4 Update Conclusion

3. Hall A collaboration meeting February 11, 2014 3 Few body form factors He 3 Form Factors He 4 Form Factors

4. Hall A collaboration meeting February 11, 2014 4 He3 form factor expected results

5. Hall A collaboration meeting February 11, 2014 5 He3 Form Factor expected results

6. Hall A collaboration meeting February 11, 2014 6 He4 Form Factor expected results

7. Hall A collaboration meeting February 11, 2014 7 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…

8. Experimental Details 20 cm long targets operated at 8K Beam current of up to 100 µA, corresponding to luminosity of 2.10 38 nuclei/cm 2 /s Allowing cross section to be measured as small as 2.10 -41 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

9. 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

10. Hall A collaboration meeting February 11, 2014 10

11. Hall A collaboration meeting February 11, 2014 11 Raw time of flight

12. Hall A collaboration meeting February 11, 2014 12 Corrected time of flight

13. Hall A collaboration meeting February 11, 2014 13 Corrected time of flight

14. Hall A collaboration meeting February 11, 2014 14 Conclusion Still setting up for full analysis New computers ordered Full production by January 2008 Preliminary results expected for summer 2008