First Six Dimensional Phase Space Measurement of an Accelerator Beam

Abstract

This Letter presents the first complete six dimensional phase space measurement of a beam in an accelerator. The measurement was made on the Spallation Neutron Source Beam Test Facility. The data reveal previously unknown correlations in the six dimensional phase space distribution that are not visible in lower dimensionality measurements. The correlations are shown to be intensity dependent.

Experimental demonstration of novel beam characterization using a polarizable X-band transverse deflection structure

“…Typically the characterization of the emittance and envelope of the beam in linear accelerators neglects the coupling terms in the transverse plane defined by the axis x − y . The measurement of the correlation terms in the beam covariance matrix 4 is either extremely time-consuming, requiring very special machine optics 5 , and/or needs masks which can be realized only for low energy beams. Often only the correlation terms of the projected beam distribution are characterized [6][7][8] , not having access to the properties of the longitudinal slices of the beam.…”

“…4 Present address: European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany. 5 Present address: Brookhaven National Laboratory, Upton, NY 11973-5000, USA. * email: barbara.marchetti@desy.de; Alexej.Grudiev@cern.ch; paolo.craievich@psi.ch…”

Nonintrusive measurement of time-resolved emittances of 1-GeV operational hydrogen ion beam using a laser comb

“…It was unclear whether these effects are important because the existing emittance measurement in the SNS front end cannot measure pulses longer than 50 μs due to the power limitation of the interceptive instrumentation. It is well known for electron linacs [13] and has been demonstrated recently for hadron beams [14] that the transverse emittance can depend on the temporal position within the bunch (slice emittance) or the energy slice within full 6-d phase space. Therefore, time-resolved measurements with sufficient temporal resolution are valuable for precise interpretation of the measured transverse emittance, meaningful comparison between measurement and simulation, or comparison between measurements at different locations.…”

Rapid charge redistribution leading to core hollowing in a high-intensity ion beam

“…At present, no model has been shown to deliver accurate representation of the loss-prone beam tails and halo. This shortcoming has been attributed to incomplete information of the initial distribution [4], motivating work at the Spallation Neutron Source (SNS) Beam Test Facility (BTF) on complete characterization of the 6D beam phase space [1].…”

“…

Recently, the first direct measurement of a full 6D accelerator beam distribution was reported [1]. That work observed a correlation between energy and transverse coordinates, for which the energy distribution becomes hollowed and double-peaked near the transverse core.

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