ROSE* Rotating System for 4D-Emittance scans Content of this talk What is the 4D beam matrix? Why would one want to know? What is ROSE and how does it work? Experimental proof that it does work! Next steps * Deutsche Patentanmeldung Nr eingereicht am beim Deutschen Patent- und Markenamt Titel der Patentanmeldung: Drehmodul für eine Beschleunigeranlage

Operateursschulung 2016 The four-dimensional symmetric beam matrix C. For a decoupled beam the off-diagonal matrix elements (red) are zero: with  x =SQRT(det  x ) in here  are the so called twiss parameters and  x the horizontal rms emittance Introduction basic equations for transverse emittance The four-dimensional rms emittance  4d is the square root of the determinant of C, and the projected beam rms emittances  x and  y are the square roots of the determinants of the on-diagonal sub-matrices

Rose summarizing the idea – uff! All values are measured using Rose at the final position. Knowing the transfer matrix they can be calculated back to the initial Position of the original not changing beam matrix C i. 100% transmission between initial and final Position is of course required for all settings.  =0°magnet setting a delivers f a, f a, f a  =90°magnet setting a delivers f a, f a, f a  =45°magnet setting a delivers  a,  a,  a  =45°magnet setting b delivers  b only 4 measurements and quite some matrix gymnastics needed to obtain the full beam matrix f + + f->i Operateursschulung 2016

EMTEX Operateursschulung 2016 L. Groening, M. Maier, C. Xiao, L. Dahl, P. Gerhard, O.K. Kester, S. Mickat, H. Vormann, and M. Vossberg, Physical Review Letter, 113, (2014)

EMTEX for mti into SIS18 success ;-) Operateursschulung 2016 *S. Appel, GSI Report (2013)

Measurement of the transverse 4d-rms beam emittance Operateursschulung 2016 Emittance measurements on a 1.7mA 238 U 28+ beam behind the skew quadrupole of EMTEX have been used to measure the 4D emittance. The emittance measurement using 6 different skew quadrupole settings assuming an uncorrelated beam at the entrance of EMTEX results in the second-moment beam matrix: Repeating the measurements for turned on skews and comparing them to the simulations, using the above uncorrelated matrix, does not fit sufficiently well! Thus it is concluded the initial beam inhabits correlations.  x = ,  y =  x = 6.11,  y = m/rad  x = 2.1,  y = 1.6 mm*mrad setting 

Operateursschulung 2016 Measurement of the transverse 4D-rms beam emittance A Mathcad routine has been developed and used to minimize a so called mismatch factor in both transverse planes simultaneously. The resulting second-moment beam matrix at the entrance is:  1 = 2.1,  2 = 1.2 mm*mrad coupling parameter t = To our knowledge this is the first successful measurement of the 4D-rms-emittance using ions. In this example removing the correlation would allow for an increase of the beam brilliance by 75%.

What is ROSE and how does it work ROSE is a standard slit grid emittance scanner comprising only one measuring plane, rotatable around the beam axis. Together with a magnetic doublet it allows to determine the full 4 dim beam matrix in aprox. 1 hour with only four emittance measurements at three different angles. Operateursschulung 2016

Rose in action Operateursschulung 2016

Commissioning beamtime at UCW Operateursschulung 2016

Two successful beam times at GUCW The first beam time using Ar 9+ mainly served to commission the hard and software of ROSE and to benchmark it against existing emittance scanners. In the first version using dry seals the vacuum was in the order of mbar getting rapidly worse. Operateursschulung 2016

Two successful beam times at GUCW GUCWDE2 ROSE mismatch factor below 10% Operateursschulung 2016

Experimental proof that ROSE is able to measure the full 4 dimensional beam matrix calculated back in front of the skew measured behind the skew Operateursschulung 2016 red skew off, blue skew on

Next step – Rose goes TK behind EMTEX Operateursschulung 2016 to reproduce the first successful measurement of the 4D-rms- emittance using ions to independent measurements of the beam coupling to confirm both techniques remove the correlation and increase the beam brilliance by ~75% Thank you for your attention