1. Laboratori Nazionali di Legnaro (Italy) DTL status A.Pisent ESS Roma 2012

2. Laboratori Nazionali di Legnaro (Italy) Group involved The participation to IFMIF-EVEDA project (RFQ realization) is based on four INFN sites (LNL,Padova,Torino,Bologna) with competences in accelerator physiscs, RF, mechanical engineering, computer controls, vacuum, brazing...... Almost all of these competences (+Naples) will be gradually involved in ESS DTL, at present –AP (coordination) –M. Comunian (beam dynamics) –F. Grespan (RF) –R.De Prisco (RF) –P. Mereu (Mechanical design, Torino) –V. Vaccaro (RF stabilization, Napoli) –C. Roncolato (vacuum) –E. Fagotti (cooling system and acc.Phys.) A.Pisent ESS Roma 2012 LNL group IFMIF EVEDA RFQ organization In INFN

3. Laboratori Nazionali di Legnaro (Italy) Collaboration on DTL since 2006, in design (F. Grespan 1 year visit at CERN for PHD thesis on DTL stabilization) participation of INFN to the construction of DTL prototype. INFN is in charge of the construction of movable tuners of linac4. 13 Sept 2011 we had a mini- workshop on main aspects of DTL realization. https://indico.cern.ch/conferenceDisplay.py?confId=152766 We are finalizing the the paper work for full access to Catia drawings (possible starting point). Collaboration with CERN linac4

4. Laboratori Nazionali di Legnaro (Italy) DTL Physics design: general parameters RF frequency352.21MHz Design Current (10% margin included)55mA Input energy3MeV Final energy (approx.)81MeV Maximum power/Tank2.2MW Maximum Surface field1.5Kilp Maximum Surface field at 3 MeV1.2kilp PMQ maximum integrated field3.8T LatticeFODO PMQ lawEquipart. Trans. Input emittance0.24mmmrad Long. Input emittance0.35mmmrad A.Pisent ESS Roma 2012 TankNo modules/CellsLength (m)Wfinal (MeV)Power (MW) 14/708.1922.08 2.0 23/265.4839.63 2.2 32/184.6754.64 2.0. 42/164.7169.21 2.1 52/144.5282.52 2.0 Total14427.57 10.3

5. Laboratori Nazionali di Legnaro (Italy) DTL Physics design: final energy RF frequency352.21MHz Design Current (10% margin included)55mA Input energy3MeV Final energy (approx.)81MeV Maximum power/Tank2.2MW Maximum Surface field1.5Kilp Maximum Surface field at 3 MeV1.2kilp PMQ maximum integrated field3.8T LatticeFODO PMQ lawEquipart. Trans. Input emittance0.24mmmrad Long. Input emittance0.35mmmrad A.Pisent ESS Roma 2012 TankNo modules/CellsLength (m)Wfinal (MeV)Power (MW) 14/708.1922.08 2.0 23/265.4839.63 2.2 32/184.6754.64 2.0. 42/164.7169.21 2.1 52/144.5282.52 2.0 Total14427.57 10.3 50-80 MeV shunt impedance higher than for any other structure (probably) 2.5 m module limit as for GSI galvanic Mohammad Eshraqi, Jim Stovall

6. Laboratori Nazionali di Legnaro (Italy) DTL Physics design: ramped field RF frequency352.21MHz Design Current (10% margin included)55mA Input energy3MeV Final energy (approx.)81MeV Maximum power/Tank2.2MW Maximum Surface field1.5Kilp Maximum Surface field at 3 MeV1.2kilp PMQ maximum integrated field3.8T LatticeFODO PMQ lawEquipart. Trans. Input emittance0.24mmmrad Long. Input emittance0.35mmmrad A.Pisent ESS Roma 2012 TankNo modules/CellsLength (m)Wfinal (MeV)Power (MW) 14/708.1922.08 2.0 23/265.4839.63 2.2 32/184.6754.64 2.0. 42/164.7169.21 2.1 52/144.5282.52 2.0 Total14427.57 10.3

7. Laboratori Nazionali di Legnaro (Italy) DTL Physics design: FODO lattice RF frequency352.21MHz Design Current (10% margin included)55mA Input energy3MeV Final energy (approx.)81MeV Maximum power/Tank2.2MW Maximum Surface field1.5Kilp Maximum Surface field at 3 MeV1.2kilp PMQ maximum integrated field3.8T LatticeFODO PMQ lawEquipart. Trans. Input emittance0.24mmmrad Long. Input emittance0.35mmmrad A.Pisent ESS Roma 2012 TankNo modules/CellsLength (m)Wfinal (MeV)Power (MW) 14/708.1922.08 2.0 23/265.4839.63 2.2 32/184.6754.64 2.0. 42/164.7169.21 2.1 52/144.5282.52 2.0 Total14427.57 10.3 2.5 m module limit as for GSI galvanic Space available for dipole steerers and BPM (@SNS FF0DD0 and @CERN FFDD) In operation Beam center can be tuned, not phase advance (should be sufficient). FODO allowes better shunt impedance if large- small DT alternance is possible (em quads?)

8. Laboratori Nazionali di Legnaro (Italy) DTL Physics design: equipartitioning RF frequency352.21MHz Design Current (10% margin included)55mA Input energy3MeV Final energy (approx.)81MeV Maximum power/Tank2.2MW Maximum Surface field1.5Kilp Maximum Surface field at 3 MeV1.2kilp PMQ maximum integrated field3.8T LatticeFODO PMQ lawEquipart. Trans. Input emittance0.24mmmrad Long. Input emittance0.35mmmrad A.Pisent ESS Roma 2012 TankNo modules/CellsLength (m)Wfinal (MeV)Power (MW) 14/708.1922.08 2.0 23/265.4839.63 2.2 32/184.6754.64 2.0. 42/164.7169.21 2.1 52/144.5282.52 2.0 Total14427.57 10.3 PMQ max=69 T/m PMQ min=28 T/m From the second Tank block design PMQ can be used.

9. Laboratori Nazionali di Legnaro (Italy) Beam envelopes Each tank begins with an empty Drift Tube (for BPM). Only a transverse matching is needed. Matching by using 2 PMQ at tank end and 2 PMQ at tank begin SNS Tank1-Tank2: 1  Linac4 DTL Tank1-Tank2: 2 

10. Laboratori Nazionali di Legnaro (Italy) F O D O F O Intertank space: 1   From first to second tank=180 mm

11. Laboratori Nazionali di Legnaro (Italy) RMS emit

12. Laboratori Nazionali di Legnaro (Italy) Phase advance/m

13. Laboratori Nazionali di Legnaro (Italy) Output phase space using Gaussian dist. (6  )

14. Laboratori Nazionali di Legnaro (Italy) DTL Physics design: error study The error study is preliminary (not done with the last tank subdivision) A.Pisent ESS Roma 2012 Emit [75%] = 6.9900 Pi.mm.mrad [ Norm. ] Emit [75%] = 8.2433 Pi.deg.MeV [ Norm. ] DTL 50 mA

15. Laboratori Nazionali di Legnaro (Italy) DTL Physics design: error study The error study is preliminary (not done with the last tank subdivision) A.Pisent ESS Roma 2012 Magnetic center respect the geometrical center shake of +/- 0.2 mm Yaw/pitch/Roll of +/-1°=17mrad Gradient error of +/-1% All errors apply together with a Gaussian (6  ) input beam distribution 100 random DTL generated. 10^6 particles i.e. 0.32 W for particle at 100 mA, 0.16 Watts for particle at 50 mA. Separate X,Y Steerer used with max force of 1.6 mT*m. Errors are the double of the CERN PMQ tender specification

16. Laboratori Nazionali di Legnaro (Italy) Steerers on FODO Lattice Using the empty space it has been put steerers X or Y almost at 90° phase advance apart for tank. 8 Steerers (2 couples for each plane) and 4 BPM for tank1. 4 steerers and 2 BPM for the other tanks. Every tank starts with a BPM. Max steerer strength of 1.6 mT*m. SNS Steerer, max 1.9 mT*m DTL 100 mA, Strength at max errors

17. Laboratori Nazionali di Legnaro (Italy) DTL 50 mA Step 1  Maximum Quad shake of X,Y ±0.2 mm; ±1°; ±1% Errors results with correction steerers

18. Laboratori Nazionali di Legnaro (Italy) Total=102 Watts Quad shake of X,Y ±0.2 mm; ±1°; ±1% DTL 50 mA

19. Laboratori Nazionali di Legnaro (Italy) In the last tanks we can increase the bore radius with the same ZTT The losses can be further decreased by increasing the DTL bore radius at high energy, above 50 MeV.

20. Laboratori Nazionali di Legnaro (Italy) Physics design conclusions Defined the DTL design for 50 mA, 5 tanks, 13 modules. An alternative 4 tanks 16 modules is quite similar with pro and cons under evaluation. Main differences of ESS design with respect to the Linac4 design: –Use of FODO lattice instead of FFDD. –Stronger PMQ in the first tank. –Use of steerers and diagnostics (BPM) inside DT. –Ramped Field E0. –Higher energy for the first inter tank transition. –Shorter intertank space: 1  instead of 2 . All these changes are in the direction of a smoother lattice. Preliminary error studies show fair tolerances (looser than for linac4 DTL) but the real evaluation has to be done on the integrated linac up to final energy. The final ZTT optimization (with the design completely defined) will allow a further improvement of the power efficiency.

21. Laboratori Nazionali di Legnaro (Italy) Elements part of DTL WP (boundaries) A.Pisent ESS Roma 2012 DTL Vacuum pumps RF network RF coupler Control system Water cooling skid RF pick ups HPRF LPRF Local Control system support INFN Alignment references General water distribution Spoke section MEBT RF window Heat exchanger Beam port flange

22. Laboratori Nazionali di Legnaro (Italy) A. Dallocchio 13.09.201122 Vacuum tank providing very high stiffness and ensuring structure stability (MASTER)Vacuum tank providing very high stiffness and ensuring structure stability (MASTER) Girder with high precision machined bushing for DTs positioning (SLAVE)Girder with high precision machined bushing for DTs positioning (SLAVE) No adjustment system (DTs alignment relies on mechanical tolerances )No adjustment system (DTs alignment relies on mechanical tolerances ) Girder (SLAVE) Tank (MASTER)

23. Laboratori Nazionali di Legnaro (Italy) A. Dallocchio 13.09.201123 DTL made of 3 TanksDTL made of 3 Tanks Inter-TanksInter-Tanks Each Tank independently supported on alignment jacks (isostatic configuration)Each Tank independently supported on alignment jacks (isostatic configuration) Each tank segment equipped with girder and DTs (~ 2m long)Each tank segment equipped with girder and DTs (~ 2m long) ESS lay out will be similarESS lay out will be similar Five tanks of 8.2+5.5+5+5+5 m, 4+3+2+2+2 modules, maximum module length 2.4 mFive tanks of 8.2+5.5+5+5+5 m, 4+3+2+2+2 modules, maximum module length 2.4 m Each tank with 2 couplers and 1 pumping stationEach tank with 2 couplers and 1 pumping station

24. Laboratori Nazionali di Legnaro (Italy) A. Dallocchio 13.09.201124 Survey Target RF Tuners Alignment Jack Post Couplers Pick-up Movable Tuners RF Wave-guide Coupler

25. Laboratori Nazionali di Legnaro (Italy) A. Dallocchio 13.09.201125 Vacuum Tank:Vacuum Tank: Material → high quality Stainless Steel 304L (UHV spec.) for ESS perhaps soft iron, like for the prototype.Material → high quality Stainless Steel 304L (UHV spec.) for ESS perhaps soft iron, like for the prototype. Very high stiffness → external diameter ~ 620 mmVery high stiffness → external diameter ~ 620 mm Internal Copper plating on fine surface finishing (Ra 0.8) to ensure low RF lossesInternal Copper plating on fine surface finishing (Ra 0.8) to ensure low RF losses Girders:Girders: Material → Aluminum alloy EN AW5083-H111Material → Aluminum alloy EN AW5083-H111 Fretted Stainless Steel bushing to ensure DTs precise positioningFretted Stainless Steel bushing to ensure DTs precise positioning Helicoflex seals ensure vacuum tightness as well as RF continuityHelicoflex seals ensure vacuum tightness as well as RF continuity Efficient cooling circuit for SPL 10% duty-cycle (precise deep-drilling of the vacuum tank)Efficient cooling circuit for SPL 10% duty-cycle (precise deep-drilling of the vacuum tank)

26. Laboratori Nazionali di Legnaro (Italy) A. Dallocchio 13.09.201126

27. Laboratori Nazionali di Legnaro (Italy) A. Dallocchio 13.09.201127 Bushing PMQ DT Assembly tool Drift Tube (including cooling circuit and precise PMQ housing) Vacuum Barrier (Helicoflex seal) Helicoflex seal

28. Laboratori Nazionali di Legnaro (Italy) A.Pisent ESS Roma 2009 CERN-LNL DTL prototype LNL contribution: maching of the tank and all components. CERN for e-beam welding of the tubes, Cu plating of the tank, final assembly and RF high power tests. High power tests concluded and published at Linac08 Prototype Tank, 1m long, machined at Cinel srl (Italy) Drift tubes, machined at Cinel srl (Italy)

29. Laboratori Nazionali di Legnaro (Italy) A. Dallocchio 13.09.201129 First reduced prototype (1 m) built by CINEL (Italy) and successfully tested at CERN

30. Laboratori Nazionali di Legnaro (Italy) DTL Tank design, copper plating Copper plating at CERN will be almost impossible due to workload; industrial or GSI alternative. Dimensions (2.5 m long and 0.6 m diameter), thickness 20um, Ru0.8 um, are challenging. R&D a full scale prototype of the tank (with design compatible with linac use) is necessaryR&D a full scale prototype of the tank (with design compatible with linac use) is necessary A.Pisent ESS Roma 2012 Tank proto painted to avoid corrosion All flanges and the contact surface of the beam are protected by PVC covers, sealed with FPM o-rings courtesy M.Malabaila Courtesy of G.Vandoni, TE-VSC

31. Laboratori Nazionali di Legnaro (Italy) DT for steerer dipoles New DT with electrical and cooling water connection for steerers (and BPM) has to be developed. Same mechanical interface if possible (perhaps looser positioning accuracy is possible). R&D A prototype of such DT can be tested at CERN in the DTL prototype.R&D A prototype of such DT can be tested at CERN in the DTL prototype. A.Pisent ESS Roma 2012 PM drift tube (courtesy of Y. Cuvet) SNS Steerer, max 1.9 mT*m

32. Laboratori Nazionali di Legnaro (Italy) Permanent magnets CERN DTL: prototypes with ASTER and European industry Elytt. We have to follow this production and possibly prototype our 70 T/m quads. It is a small serie (72 quads) other suppliers are possible. Cinel has experience with PM for example for ECR exapoles. A.Pisent ESS Roma 2012 (courtesy of A. Lombardi) 16 silver-plated screws 16 pole pieces 8/27/2015 This is not the final quad!!!!

33. Laboratori Nazionali di Legnaro (Italy)

34. Power couplers We have experience with design of high power coupling loops, but the coupler chosen by CERN worked very well in the tests of the DTL prototype. The design has improved with the use of posts for tuning of the coupling constant . Is a 2 MW coupler possible? (R&D)Is a 2 MW coupler possible? (R&D) A.Pisent ESS Roma 2012 Coupling to pi mode cavity TM (courtesy of Patricia Ugena Tiradof)

35. Laboratori Nazionali di Legnaro (Italy) Tuning with movable tuners or water temperature We have experience with both the approaches (TRASCO RFQ and linac3 RFQ) Movable tuners react faster, but with high duty cycle t regulation is more reliable, without sliding contacts. We have not yet reliable thermal simulations to choose. A.Pisent ESS Roma 2012

36. Laboratori Nazionali di Legnaro (Italy) Accelerator assembly and installation CERN DTL will be assembled (with DT aligned) in a dedicated hall in surface outside the tunnel. The second and third DTL tanks (about 8 m long) will be the largest pieces to be introduced in the tunnel. If the same approach is implemented of ESS DTL, such installation has to be considered for building design A.Pisent ESS Roma 2012

37. Laboratori Nazionali di Legnaro (Italy) Conclusions Plan for prototyping Mechanical design based on tank design developed at CERN (accurate positioning and fixing of tube position, metallic gaskets). Our design has FODO lattice, steerers or BPMs inside DT, field ramping short transition We plan to develop DT for steerers or diagnostics, with electrical connections out of the stem. Such DT will be tested at high power in the DTL prototype (developed by CERN and INFN) PM with trapezoidal components should be prototyped Construction and tests perspective –Tank and DT can be built in local industry (see again prototype). Brazing and e-beam welding are possible in 70 km distance. –We are looking for an industrial partner for copper electro-plating, the design is compatible with GSI galvanic. Full scale prototyping of a tank would be beneficial. –INFN (LNL and PD) has the structures for high precision milling, vacuum brazing, CMM, EDM, RF measurements, laser tracking, assembly of the tank and low power tests. –Moreover a power system could be installed in LNL for high power tests and conditioning of couplers and tanks (dedicated space under discussion with management).