1. Measurement of Transverse Emittance in ASTA John Nocita Amber Johnson John Diamond August 8, 2013

2. Overview Emittance Hardware Vacuum equipment Imaging Scintillation OTR Software ACNET Existing tools EmittanceCalculator Conclusions, Future Direction

3. Emittance Emittance is beam size in phase space Εn = ΥβE is conserved through acceleration Monitor beam, design components Gaussian approximation of beam  RMS emittance http://www-pnp.physics.ox.ac.uk/~delerue/

4. Emittance

5. Hardware Need to test angular acceptance, field of view: reading in pixels, computing in microns. - 27.8 microns / pixel Alex Lumpkin

6. Targets / Slits Beam cage : prevent wakefield effect Scintillator crystal OTR foil

7. Slit imaging Slit spacing for divergence measurements Tungsten blocks with 50 um spacing Known slit size  measurable divergence

8. Imaging techniques Scintillation  Higher output; limited by crystal effects OTR  Better spatial, temporal resolution Both destructive

9. Scintillation Decay time = 70 ns 8 photons per KeV

10. Optical Transition Radiation Angle of peak electron emission is 1/γ A charged particle transitioning between media with different dielectric constants must rearrange electric fields  Photons emitted on sub- picosecond timescale From Alex Lumpkin

11. ACNET ImageTool Emittance Calculator Cameras Background Subtraction Target steppers

12. A0PI Emittance calculator ImageTool

13. Fitting multiple Gaussians Iterative methods need good initial condition Peak selection – ease of use Simulated phase space image

14. EmittanceTool Interface for cameras (ACNET) Manual peak selection Fits to data Calculation of phase space ellipse

15. Conclusions and Future Directions Adaptation of A0PI functions to ACNET- compatible format Specific to ASTA  Camera signatures  beam energy, drift length  More automated calculation Flexible – optimized to present hardware, software conditions but will adapt to beam Hopefully, a useful tool through construction

16. Thanks to: Amber Johnson for guidance and support. John Diamond for countless good ideas and advice Alex Lumpkin for great explanations The Fermilab Accelerator Division for creating a welcoming and helpful atmosphere Eric Prebys, Linda Spentzouris, and Carol Angarola for all their work to make things go smoothly