1. ZQNA Electrostatic Quadrupoles for ELENA Transfer Lines 1.Conceptual design 2.Performance 3.Engineering details 4.Interfaces 5.Production planning D. Barna, W. Bartmann, P. Moyret, R. Ostojic, J-F. Poncet IIC, 31 July 2014

2. Documentation Engineering Specification: Mechanical drawings in CDD under “AD_ZQNA%”.

3. Functional requirements - 1 Strength – Quadrupoles: 6 m -1 (100 keV antiproton beam) – Correctors: 10 mrad (100 keV antiproton beam) Aperture – Separation between electrodes: at least 60 mm mechanical aperture – All other components of the assembly (e.g. flanges) should have larger diameter. Field homogeneity – “Good field” region: radius 20 mm – Relative change in the good field region: < 10 -3 Dimensions – Distances between electrodes and ground: greater than 10 mm – Aperture limiting electrodes (field clamps) to be included to minimize field leakage and coupling between electrodes. – The overall length and diameter of the assembly should be as small as feasible.

4. Functional requirements - 2 Electrical – Conservative values of the nominal design voltages should be chosen (~ 5 kV for the quadrupoles, ~2 kV for the correctors). – All non-active electrodes must be properly grounded. – Operation in quasi-static mode: no requirement on the switching time. Powering – The quadrupoles are powered either individually or as a string. The polarity of the quadrupole is fixed. If necessary, the changes of polarity will be made by modifications in the external circuit. The operating range is from nominal voltage to as low as 100 V. – The correctors must be powered individually, with variable voltage and polarity. – The voltage stability: 10 -4 of the nominal value for the quadrupoles. 10 -3 for the correctors. Alignment tolerances – The changes in the beam orbit due to assembly misalignments must be small compared to the beam size in the transfer lines. Vacuum – The assembly must be compatible with the vacuum requirements of the beam lines and must be compatible with bakeout up to 250 o C. Interlocks – The power supplies must be interlocked with the vacuum system in each vacuum sector, and must be short-circuit proof to avoid damage in case of a rapid vacuum loss.

5. Conceptual design Standard electrostatic quadrupole assembly (ZQNA): – two quadrupoles – one horizontal and one vertical corrector – common vacuum chamber – used in all locations, 60 units in total. Quadrupoles powered independently with a focusing or defocusing polarity (or with the same polarity if more strength needed). H/V correctors powered independently in a bipolar arrangement. Electrode assembly mounted on a reference flange, which also serves for rigid attachment of a BPM. Assembly fully symmetric around the vertical axis and can be mounted with the fixed flange (BPM) on the left or right.

6. Main parameters Quadrupole-1CorrectorsQuadrupole-2 Aperture60 mm Nominal strength6 m -1 10 mrad6 m -1 Nominal voltage 12 kV (±6 kV wrt ground) 6 kV (±3 kV wrt ground) 12 kV (±6 kV wrt ground) Min electrode-ground distance 10 mm Electrode length100 mm37+37 mm100 mm PolarityF or DH and VF or D Capacitance104 pF (tbc) Required Voltage stability 10 -4 10 -3 10 -4 HV feedthroughs 2-pin SHV-10kV on DN35CF flange 4-pin SHV-10kV on DN35CF flange 2-pin SHV-10kV on DN35CF flange Length (flange-to-flange) 390 mm Vac chamber outer dia.204 mm Upstream flangeDN200CF (fixed) Downstream flangeDN200CF (rotatable) Mass30 kg

7. Performance Quadrupoles – StrengthL eff = 108 mm, V max =±6 kV – Field homogeneityQuad-like shape of aperture plate – Field perturbations from connectionsOK – Electrical circuit104 pF (tbc) Correctors – StrengthL eff = 55 mm, V max =±3 kV – Field homogeneityDecoupled and rounded H/V electrodes – Electrical circuit(tbc)

8. Engineering details Vacuum vessel Electrodes and supporting system HV connectors Assembly support Interfaces

9. Vacuum vessel AISI 316L body, 2 mm wall, 204 mm OD. AISI 316LN, DN200 CF flanges (fixed and rotatable). Other elements in AISI 304L. Inside wall NEG coated.

10. Electrodes All materials: AISI 316L, without NEG coating. All electrodes supported off four rails with insulator blocks made of alumina 12 mm high.

11. Electrode support Four rails provide precise positioning of the electrodes with respect to the assembly axis. The rails are connected to the DN200 CF flanges through flange inserts. On the upstream side (fixed DN200 CF flange), the fixation is rigid. On the downstream side (rotatable DN200 CF flange), the rails are supported using sliding bolts, which allow thermal expansion of the assembly during bakeout.

12. HV connectors HV feedthroughs with spring loaded pins. Two/four SHV feedtroughs for quadrupole/corrector connections on DN35CF flanges. Compatible with bakeout to 250 C. One quote received. Waiting for response of other (potentially cheaper) provider for the 4-feedthrough flange.

13. Assembly support Four support blocks for connection to the alignment table. Clearance between the HV connectors and the alignment table at least 200 mm. Appropriate features on the table allow controlled movements of the assembly during thermal expansion (bakeout). The alignment table allows horizontal, vertical and longitudinal alignment of the assembly of ±20 mm, and provides longitudinal fixed point counteracting vacuum forces.

14. Interfaces 1) Beam vacuum system: two DN200 CF flanges, fixed on the upstream side (1a), and rotating on the downstream side (1b). 2) Alignment table: two support blocks upstream side, two support blocks downstream side. 3) HV powering cables: two 2-pin SHV feedthroughs, one 4-pin SHV feedthrough. 4) Alignment: two target holders, one on the upstream side and one on the downstream side. 5) Handling tools: four M10 threads. 1a 2 3 4 1b 5

15. Production planning Requested availability – Phase-I installation: 10 ZQNA assemblies by June 2015; – Phase-II installation: 50 ZQNA assemblies by Dec 2016;

16. Production planning –EN/MME 12 units 21 May 2015 48 units 24 Nov 2015

17. Next steps … Complete and approve the Engineering Specification – Aug 2014 Complete and approve design file– Aug 2014 Issue orders for component fabrication – Sep 2014 Prepare Test and Acceptance Procedure– Nov 2014