G 0 PC Installation and Beam Studies Stephanie Bailey Riad Suleiman

Presentation Outline Pockels Cell Installation (Injector) Electron Beam Studies (up to 100 KeV) Electron Beam Studies (up to 5 MeV) Electron Beam Studies (up to BSY)

Pockels Cell Installation (Injector) January 14-20, 2006 What did we accomplish? –Characterized Intensity Asymmetry (IA) Cell: λ/4, 20° Measured dependence of intensity loss on waveplate angle : 1.24%/ ° (25% at 20°) Measured dependence of intensity asymmetry on voltage : ppm/V –Aligned Pockels Cell (PC) Degree of linear polarization = 4.88% Degree of circular polarization = 99.88% Minimized x and y position differences.

Pockels Cell Installation Birefringence Effects –The presence of a gradient in the phase introduced by the PC will result in varying linear polarization across the photocathode. –Helicity correlated position differences result. Steering Effects –PC can act like voltage controlled lenses –If beam is off-center, it can be steered. –Helicity correlated position differences result

Pockels Cell Installation Results January 14-20, 2006 Steering (LP OUT) IHWP INIHWP OUTGoal ΔxΔx0.11 ± µm-0.07 ± µm < 0.1 µm ΔyΔy-0.16 ± µm 0.10 ± µm < 0.1 µm Δcharge ± 9.51 ppm ± ppm Birefringence (LP IN) IHWP INIHWP OUTGoal ΔxΔx7.39 ± µm ± µm < 6 µm ΔyΔy3.88 ± µm ± µm < 6 µm Δcharge1.56E4 ± 157 ppm -2.54E4 ± 169 ppm Electrical Pickup ΔxΔx0.008 ± µm ΔyΔy ± µm Δcharge0.043 ± 1.24 ppm InjectorHappex ΔxΔx< 0.3 µm ΔyΔy Δcharge w/ photocathode 3X larger in injector w/ photocathode 20X smaller in injector

Electron Beam Studies (up to 100 KeV) January 28, 2006 (80 μA, Wien = 0°) IHWP OUT IHWP IN RHWP = 0° -8.6 ppm/V Slope is too small. Move to a better angle.

Electron Beam Studies (up to 100 KeV) January 28, 2006 (80 μA, Wien = 0°)

IHWP OUT IHWP IN RHWP = 120° 14.3 ppm/V Slope is better.

Electron Beam Studies (up to 100 KeV) January 28, 2006 (80 μA, Wien = 0°) Summary –All of the position differences are less than 0.3 um. –Charge asymmetry can easily be controlled with the size of the PITA slope. Intensity Asymmetry (IA) Cell –Measured dependence of intensity asymmetry on voltage : ppm/V

Electron Beam Studies (up to 5 MeV) February 1, 2006 (20 μA,Wien = 90°) IHWP OUT IHWP IN RHWP = 120° ppm/V

Electron Beam Studies (up to 5 MeV) February 1, 2006 (20 μA, Wien = 90°) Summary –Except for a few BPMs (Δy, IHWP = IN, KeV region), all of the position differences are less than 0.3 um. –Charge asymmetry can easily be controlled with the size of the PITA slope.

Friday, February 3, 2005 Hall C laser unlocked. Matt and John did their best to put the Hall C beam back on the original line through the pockels cell and to the photocathode. We may see different helicity correlated asymmetries.

Electron Beam Studies (up to BSY) February 3, 2006 (687 MeV,10 μA, before Chao’s accelerator matching ) IHWP OUT

Electron Beam Studies (up to BSY) February 3, 2006 (687 MeV,10 μA, before Chao’s accelerator matching ) Helicity Magnet 1 Acharge (ppm/DAC) Dx (nm/DAC) Dy (nm/DAC) Dr (nm/DAC) IPM0L IPM0L IPM0L IPM0L IPM0L IPM0R C C Helicity Magnet 2 Acharge (ppm/DAC) Dx (nm/DAC) Dy (nm/DAC) Dr (nm/DAC) IPM0L IPM0L IPM0L IPM0L IPM0L IPM0R C C Helicity Magnet 3 Acharge (ppm/DAC) Dx (nm/DAC) Dy (nm/DAC) Dr (nm/DAC) IPM0L IPM0L IPM0L IPM0L IPM0L IPM0R C C Helicity Magnet 1 Acharge (ppm/DAC) Dx (nm/DAC) Dy (nm/DAC) Dr (nm/DAC) IPM0L IPM0L IPM0L IPM0L IPM0L IPM0R C C

Electron Beam Studies (up to BSY) February 5, 2006 (687 MeV, 20 μA, after Chao’s accelerator matching)

IHWP IN IHWP OUT RHWP = 20° -15 ppm/V RHWP = 160° -20 ppm/V

Electron Beam Studies (up to BSY) February 5, 2006 (687 MeV, 20 μA, after Chao’s accelerator matching) Helicity Magnet 1 Acharge (ppm/DAC) Dx (nm/DAC) Dy (nm/DAC) Dr (nm/DAC) IPM0L IPM0L IPM0L IPM0L IPM0L IPM0R C C Helicity Magnet 2 Acharge (ppm/DAC) Dx (nm/DAC) Dy (nm/DAC) Dr (nm/DAC) IPM0L IPM0L IPM0L IPM0L IPM0R C C Helicity Magnet 3 Acharge (ppm/DAC) Dx (nm/DAC) Dy (nm/DAC) Dr (nm/DAC) IPM0L IPM0L IPM0L IPM0L IPM0R C C Helicity Magnet 4 Acharge (ppm/DAC) Dx (nm/DAC) Dy (nm/DAC) Dr (nm/DAC) IPM0L IPM0L IPM0L IPM0L IPM0R C C

Electron Beam Studies (up to BSY) February 5, 2006 (687 MeV, 20 μA, after Chao’s accelerator matching) Summary –We see different helicity correlated asymmetries. –Steering offset ~0.4 um –Need to re-align Pockels Cell before run