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PRISM experiment on EMMA. Test Non-Scaling optics for PRISM ¼ of the synchrotron oscillation takes ~3 turns in EMMA and ~6 turns in PRISM . Experimental steps (version I):
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PRISM experiment on EMMA • TestNon-Scaling optics for PRISM • ¼ of the synchrotron oscillation takes ~3 turns in EMMA and ~6 turns in PRISM. • Experimental steps (version I): • Inject into EMMA at fixed energy from ALICE with different conditions (transverse amplitudes)with RF on (voltage and phase set to stationary bucket). • Extract after ¼ (3/4) of synchrotron oscillation and measure energy and ToF. • Analyse the data and reproduce the longitudinal phase space as a function of the transverse amplitude J. Pasternak, R. D’Arcy, bdm
PRISM experiment on EMMA • Experimental steps (version II): • Inject into EMMA at different equivalent energies with different conditions (transverse amplitudes) with RF on (voltage and phase set to stationary bucket). • Extract after ¼ (3/4) of synchrotron oscillation and measure energy and ToF. • Analyse the data and reproduce the longitudinal phase space as a function of the transverse amplitude. • Can we measure the emittancegrowth ? • Do we need more initial RF phases or energies ?
PRISM experiment on EMMA • Not much progress made in the last run … • Only really had ~ 6 hours and remember • Need to extract the beam & measure energy • Everything before extraction has to work … • Only have pencil beam – cannot model directly • Take 3 or more bunches to represent PRISM beam • Show rotation that way by changing RF phases • Find stable fixed point of RF bucket • Vary phase & extract ‘beamlets’ (small bunches) • Lower energy / higher energy
PRISM experiment on EMMA • Have established extraction reliably after n turns • Good transport (though intensity not sufficient to get to Faraday cup at the end of line …) • Beam centred down extraction line • However n was small (only 1/2, 3/2, 5/2 turns) • Did not have RF capture of beam which would have been ideal for this experiment • Saw beam on YAG01 & YAG03 in extraction • Have script to scale all magnets in extraction line according to energy by Jaroslaw • Make images on YAGs identical
PRISM experiment on EMMA • YAGs used highlighted with red circles
PRISM experiment on EMMA • Can use ‘overlay’ function with images to do this • Images do look very similar but reduced intensity • Should be able to ‘match’ centroids easily • This should increase accuracy of results … YAG01 – 1/2 turn, no RF YAG03 – 1/2 turn, no RF
PRISM experiment on EMMA • Can now turn RF on • Scale magnets • Try to restore beam to the same position YAG01 – 3/2 turns, no RF YAG03 – 3/2 (top), 5/2 turns, no RF
PRISM experiment on EMMA • All images without correction (no YAG3 for 3/2 turns - acceleration) • Behaviour as expected • Now use scaling program YAG01 – 1/2 (top), 3/2 turns, RF on YAG03 – 1/2, RF on
PRISM experiment on EMMA YAG01 – 3/2 (top), 5/2 turns, RF on, scaling YAG03 – 3/2 (top), 5/2 turns, RF on, scaling
PRISM experiment on EMMA • Conclusions • Need RF capture of beam to do this well but EMMA was not cooperating on this … • Extraction line difficult to use as beam has been extracted pragmatically so far … • Need precise model for this so as to know initial parameters in better detail • Have good idea what needs to be done (I think) • Feedback to Jaroslaw or myself • Next run hopefully ~ March 2012 • Many things will have changed by the time we come up again – hopefully this does not hinder us but …