Undulators For Intense Gamma Ray Beams Ayash Alrashdi Supervisor Dr. Ian Bailey Lancaster University

Outline Introduction. Introduction. HUSR/GSR Software. HUSR/GSR Software. ILC Gamma-Ray Source. ILC Gamma-Ray Source. ILC HU Measured and Simulated Magnetic Field. ILC HU Measured and Simulated Magnetic Field. Electron Trajectory Inside ILC Helical Undulator. Electron Trajectory Inside ILC Helical Undulator. ILC Photon Spectra. ILC Photon Spectra. Optimization of the Collimator Shape. Optimization of the Collimator Shape. Conclusion. Conclusion. A. Alrashdi, CI GradFest 27/11/2014

Introduction Required photon flux (approximately photon/s ) for high-luminosity electron positron colliders such as the ILC. The TDR parameters for the baseline positron source at 150 GeV are assumed throughout this talk. 3.9x10 14 e + /s A. Alrashdi, CI GradFest 27/11/2014

HUSR/GSR Software HUSR/GSR developed at Cockcroft Institute by David Newton. HUSR/GSR simulates a photon spectrum from an arbitrary magnetic field map. Using different arbitrary maps is possible in HUSR e.g. include errors in the magnet, tapering, etc. A. Alrashdi, CI GradFest 27/11/2014

ILC Gamma-Ray Source Small Secondary Facility A possible design for the ILC positron source with secondary experimental station. Approximately 93% of the photon beam will pass through the target Now, in order to explore HUSR/GSR, we proposed a new idea A. Alrashdi, CI GradFest 27/11/2014

ILC HU Measured and Simulated Magnetic Field. We have developed code in Mathematica to generate a simulated, realistic magnetic field based on the errors from any measured field map. We introduced errors in the simulated magnetic field map based on the measured magnetic field of the ILC prototype undulator. We compared the discrete Fourier Transform of the x- projection of the magnetic field within the undulator for the measured data and simulated data to tune the error parameters used in the model. A. Alrashdi, CI GradFest 27/11/2014

ILC HU Measured and Simulated Magnetic Field. Measured Simulated Design Period A. Alrashdi, CI GradFest 27/11/2014

Electron Trajectory Inside ILC Helical Undulator. We use these two programs with a measured map from the ILC helical undulator prototype constructed some years ago. We use this map inside the HUSR/GSR software to calculate the trajectory of an electron inside this map and the resulting photon spectra. We have generated many simulated field maps and used them to explore deviations in the electron trajectory and the impact on the spectrum. A. Alrashdi, CI GradFest 27/11/2014

Standard Deviation of Electron trajectories from 20 simulated maps. Electron Trajectory Inside ILC Helical Undulator. Electron Trajectory from Ideal Map Electron Trajectory from Measured Map Electron Trajectory from Simulated Map A. Alrashdi, CI GradFest 27/11/2014

ILC Photon Spectra Spread of gamma-ray spectra from the simulated field maps. The flux of the peak corresponding to 1.9x10 14 photon/s A. Alrashdi, CI GradFest 27/11/2014

Optimization of the Collimator Shape. We adapted the HUSR/GSR software to automatically detect the positions of the observation points which give spectra in accordance with the users requirements. We designed the required spectra (from user). We select those observation points which has a spectra which lies fully underneath the designed spectra or exactly equal to the designed spectra. Based on the results we can decide which collimator shape would give the required spectra. MethodMethod A. Alrashdi, CI GradFest 27/11/2014

Optimization of the Collimator Shape. A. Alrashdi, CI GradFest 27/11/2014 Current Gamma-Ray Sources: HIGS (10 8 photon/s, Bandwidth 5%-10%) at Duke University, USA. ELI-NP is being designed (8x10 8 photon/s, Bandwidth 0.5%). The flux of the peak corresponding to 8x10 13 photon/s Red means there should be a hole.

Conclusion Good agreement between the simulated field map with errors introduced and the measured field map. By evaluating the spectrum using a numerical code with a high accuracy and realistic simulated data we hope to turn this initial study into a rigorous investigation. Based on preliminary results, we believe there is a good chance that the spent ILC gamma-ray beam could be put to good use. Further studies show these preliminary results are consistent with developing a gamma-ray facility for nuclear physics downstream of the ILC positron target. A. Alrashdi, CI GradFest 27/11/2014