HP-PS beam acceleration and machine circumference A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13 On behalf of HP-PS design team

Layout -Reflexion on Machine circumference -Acceleration for LAGUNA Beam -Acceleration for LHC/FT beams A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Layout -Reflexion on Machine circumference -Acceleration for LAGUNA Beam -Acceleration for LHC/FT beams A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

The HP-PS is a machine designed for high intensity beams for neutrinos production. However, due to high cost of such a machine and present budget restrictions, one good way to see our project accepted, consists, for the accelerator part, on designing a flexible machine. Applied to the CERN accelerator complex, a flexible machine would be able to accelerate both LAGUNA beams and CERN beams (LHC and Fixed-Target beams). That’s why we decided to modify the HP-PS in order to improve it’s flexibility. Introduction A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

LHC SPS PS PSB Experiments & Test Beams LINAC 4 LP - SPL CN2PY Target 2 MW HP-PS 2 Hz 1 Hz 160 MeV 4 GeV 50 / 75 GeV Inj. / Extr. Collimation Acceleration 3-fold Symmetry Basic scenario for CERN Complex with HP-PS A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

LHC SPS PS PSB LINAC 4 LP - SPL CN2PY Target 2 MW HP-PS 2 Hz 1 Hz 160 MeV 4 GeV 50 / 75 GeV Inj. / Extr. Collimation Acceleration 3-fold Symmetry New possible scenario for CERN Complex with HP-PS A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13 LHC / FT beams

HP-PS as injector for SPS In order to allow good beam transfer between HP-PS and SPS, ring must be synchronized. It is achieved by adjusting the size of the HP-PS. Circumference ratio between HP-PS and SPS must be a integer, or a ratio of integer. Present ratio : C SPS / C HPPS = possible solutions matching requirements are close to the present ratio : C SPS / C HPPS = 6and C SPS / C HPPS = 5.5 Ratio of 6 implies a circumference diminution of ~20m. This is not reasonably sustainable due to constraints on magnets strengths. Ratio of 5.5 has been chosen. A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

HP-PS beam structureLAGUNA beam RF harmonic 168 – 25 ns bunch spacing – 157 bunches – 11 empty buckets as extraction kicker gap (275 ns gap for 250 ns rise time) Batch length at extraction is μs This is the beam structure to the target (and if required the SPS for LHC) 157 bunches 11 empty buckets T rev (extr.) = μs 275 ns 8 A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

HP-PS to SPS for LHC Bunch to bucket transfer with 25 ns bunch spacing – 157, 314, 471, 628, 785 bunches for 1, 2, 3, 4 or 5 batches SPS injection kicker rise time dominates HP-PS extraction kicker rise time – Inter-batch gap 500 ns (SPS) – Up to 5 batches can be transferred to SPS SPS extraction kicker gap of 975 ns sufficient for 950 ns rise time. – Kicker flat top length to be checked – Impact of LHC filling scheme with 500 ns gaps to be checked. Batch 1 Batch 2 Batch 3 Batch 4 Batch 5 SPS T rev = μs μs 975 ns Up to 5 HP-PS fast extractions 500 ns 9 A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

HP-PS to SPS for FT with 5–turn bunched MTE Bunch to bucket transfer with 25 ns bunch spacing, using 5-turn MTE – 5 x 157 = 785 bunches (out of 4620 SPS buckets => 175 occupation) HP-PS MTE fast bump gap assumed identical to extraction kicker rise time. 5-turn MTE can be transferred to SPS – One single SPS injection kick with flat op length of 21 μs SPS extraction: – In case of FE the kicker gap of μs is largely enough for the 950ns kicker rise time – In case of SE the beam will be de-bunched, filling all the gaps and no extraction kicker gap needed. Turn 1 Turn 2 Turn 3 Turn 4 Turn 5 SPS T rev = μs μs 2.375μs 1 HP-PS cycle 275 ns 10 A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

HP-PS to SPS for FT with 5–turn de-bunched MTE Beam de-bunched in HP-PS prior to 5 turn MTE extraction – (5 x 3.917) μs occupied for μs in total  84.5% bucket occupation HP-PS MTE fast bump gap assumed identical to extraction kicker rise time. 5-turn MTE can be transferred to SPS – One single SPS injection kick with flat top length of 21 μs. SPS extraction: – In case of FE the kicker gap of μs is largely enough for the 950ns kicker rise time – In case of SE the beam will be de-bunched, filling all the gaps and no extraction kicker gap needed. Turn 1 Turn 2 Turn 3 Turn 4 Turn 5 SPS T rev = μs μs 2.375μs 1 HP-PS cycle 275 ns 11 A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Layout -Reflexion on Machine circumference -Acceleration for LAGUNA Beam -Acceleration for LHC/FT beams A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Beam for LAGUNA : stability After calculation the longitudinal emittance must be increased up to 1 eV.s in order to maintain Threshold value above space charge impedance. A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Beam for LAGUNA : Voltage Voltage has been recalculated using fixed filling factor of 0.9 in momentum and a longitudinal emittance of 1.0 eV.s with new magnetic field. 2.1 T 0.19 T A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Beam for LAGUNA : Bunch / bucket properties Bunch length during acceleration Beam and bucket momentum spread during acceleration. A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Beam for LAGUNA : transition gamma All previous calculations have been done taking into account same transition gamma than for present design. Due to high intensity and high transition gamma, the longitudinal emittance which maintain beam stable is much higher than PS2, leading to high voltage. One way to decrease this emittance (thus maximum voltage) would be to “play” with transition gamma. A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Layout -Reflexion on Machine circumference -Acceleration for LAGUNA Beam -Acceleration for LHC/FT beams A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Beam for SPS : constraints -Longitudinal emittance of 0.5 eV.s -Maximum bunch length at extraction 4 ns -Maximum intensity 2.5*10 11 pppb A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Beam for SPS : Voltage with bunch compression 455 kV 4 ns 0.5 eV.s A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Beam for SPS : transition gamma As for LAGUNA beam calculations have been made for I transition gamma. It is thus possible to calculate the admissible intensity as a function of transition gamma. A.LachaizeLAGUNA-LBNO General meeting Paris 18/09/13

Conclusion -A new HP-PS with improved compatibility with CERN complex is under design -Work on collective effects is on progress -Check on RF cavities performances is on progress