Darmstadt 2016 – wissenschaftliches Programm

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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 12: Beam Diagnostics I

AKBP 12.4: Vortrag

Donnerstag, 17. März 2016, 14:45–15:00, S1/05 23

High-accuracy electron beam energy measurement at the Mainz Microtron — •Philipp Herrmann — Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz

The Mainz Microtron MAMI delivers an electron beam of up to 1.6 GeV. The absolute energy is measured inside the third stage of the accelerator with an accuracy of δ E_beam = 160 keV independent of the beam energy, with an energy spread σ_beam < 13 keV and long-term drifts of less than 1 keV when stabilized. To obtain an absolute energy measurement within δ E_beam ∼ 20 keV uncertainty, a 42^∘-dipole of the beam-line leading to the spectrometer facility is used as a high-accuracy beam spectrometer. A high-precision field mapping device was developed and a dedicated beam detection system of RF cavity position monitors and YAG:Ce screens was implemented. The goal is to achieve 10 µT and 10 µm uncertainties in the field map. The electron beam deflection is expected to be measured with δ θ/θ < 10⁻⁵. The overlay of the magnetic field map and the actual beam position during calibration is achieved by a collinear laser system. With the calibrated beam the absolute momentum calibration of the three high-resolution spectrometers at MAMI can be improved. Key factors will be the setup and automation of the field mapping with the desired precision, combined with the global positions of beam and field.