Beam extraction - 50th anniversary of the CERN Proton Synchrotron

More documents

Recommendations

Info

ump in its present configuration and in the proposed one is shown in Fig. 30. The non-closure of the original version of the slow bump is corrected by the larger number of independent correctors. It is worth mentioning that the new version of the slow bump entails a number of changes also at the level of the power converters [44]. 7.2.2 Fast bump The MTE scheme is based on a fast bump around the magnetic septum in SS16 (see Fig. 31, top). Bump amplitude (mm) 60 50 40 30 20 10 0 -10 Origin of s coordinate: SS54 0 100 200 300 400 500 600 700 s coordinate (m) Fig. 31: Top: PS Complex layout, indicating the location of the fast pulsed magnets (red dots) and the magnetic septum in SS16 (blue dot) implied in the new PS multi-turn extraction scheme. The elements named DFA correspond to the devices called ERD. Bottom: Example of the bump generated by the new kickers for the extraction of the fifth turn, i.e., the beam core 26
Fast pulsed magnets (kickers), to be located in SS13 and SS21, will create a nearly closed bump for the beamlets in the first four turns. To close it perfectly, an existing kicker in SS09 will be used. The core beam needs to be moved out by more than twice the distance of the other four beamlets. One additional kicker, to be located in SS04, in conjunction with the existing KFA71–79 system will kick out the remaining beam in the fifth turn. Two existing emittance reduction fast dipoles in the TT2 transfer line will be used to correct the trajectory of the beamlets. As an example, the fast bump generated by the kickers for the extraction of the fifth turn is shown in Fig. 31 (bottom). The turn-by-turn variation of the extraction conditions will be corrected by dedicated kickers in the TT2 transfer line. The new system re-uses a maximum of existing de-commissioned and reserve equipment to minimize delays and reduce the cost. A summary of the main parameters of the PS ring kickers is given in Table 2. Table 2: Required kicker strength and rise time values (10% and 90%). The strengths are computed for a beam rigidity of 46.68 Tm. Turn BFA9 (mrad) KFA13 (mrad) KFA21 (mrad) KFA71 (mrad) KFA4 (mrad) 1 −0.114 1.839 1.887 0 0 2 −0.114 1.839 1.887 0 0 3 −0.114 1.839 1.887 0 0 4 −0.114 1.839 1.887 0 0 5 −0.114 1.839 1.887 −1.834 −0.400 Rise time (ns) 340 350 350 70 80 Maximum strength (kV) 35 80 80 9×80 80 7.2.3 Sextupoles and octupoles The creation of stable islands is possible by setting the linear and non-linear magnetic components in the PS ring. This is achieved by acting on the pole-face windings, figure-of-eight loop, plus four sextupoles and two octupoles dedicated to MTE operation. Whereas the four sextupoles already existed, three new octupoles, two operative magnets plus one spare, have been designed, constructed, magnetically measured, and then installed. The octupolar gradient difference between the three magnets is well below the 0.3%, as shown in Fig. 32 (left), where also the octupolar gradients versus current are presented. The magnet saturation occurs at about 500 A. Two octupoles have been installed, one in SS39 and the other SS55, in a tightly packed installation together with two sextupoles, shown in Fig. 32 (right). 27
Page 1 and 2: Beam extraction 1 Introduction In t
Page 3 and 4: high-quality cable used for the PFN
Page 5 and 6: 3.1 Integer resonance extraction 3.
Page 7 and 8: A last improvement came in 1971 wit
Page 9 and 10: the semi-quadrupole began to raise
Page 11 and 12: Fig. 11: Left: electrostatic septum
Page 13 and 14: 3.3.3 Performance of the SE61 extra
Page 15 and 16: After the proposal, an experimental
Page 17 and 18: 80 70 60 β x β y D x SS31 50 40 S
Page 19 and 20: 3.3×10 13 protons per PS batch. Am
Page 21 and 22: Fig. 25: 3D view of the beamlets al
Page 23 and 24: Fig. 27: Sequence of beam profile d
Page 25: they were done over two consecutive
Page 29 and 30: Fig. 34: Upper: Cross-section of th
Page 31 and 32: Fig. 36: Intensity of a MTE de-bunc
Page 33 and 34: [16] F. Galluccio, T. Risselada, Ch

Beam extraction - 50th anniversary of the CERN Proton Synchrotron

Create successful ePaper yourself

Delete template?

Save as template?