General specifications LHC Crab cavities O Capatina L

General specifications LHC Crab cavities O. Capatina, L. Alberty, K. Brodzinski, R. Calaga, E. Jensen, V. Parma – CERN OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 1

Overview • Cavity • Tuning • Helium tank • Magnetic shielding OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 2

Bi-phase helium tube SPL beta = 1 cavity assembly Helium Tank Beam pipe Tuner Cavity Magnetic shielding HOM Coupler RF Power Coupler OC, VP, 7/November/2012 TTC Meeting 3

Functional specification OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 4

Cavity • Parameters Parameter Units Value Frequency MHz See next page 1 MV 3. 3 (pushed=5. 0) Cavity b Design gradient R/Q W Q 0 >1 x 1010 Qext 1 x 106 OC, 13/December/2012 LHC Crab Cavity Engineering Meeting >300 5

Cavity • Parameters Parameter Units LHC Beam Energy Ge. V 7, 000 Frequency MHz 400. 79 400. b 400. c OC, 13/December/2012 LHC Crab Cavity Engineering Meeting SPS 55 120 270 6

Cavity • Dimensions R. Calaga, Superconducting Technologies Workshop, Dec. 2012 OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 7

Cavity • Dimensions • RF design for internal shape at cold • Design for manufacturing by scaling: • Warm (room temperature)/cold shrinkage • Shape modification due to EP, BCP, . . • Deformation due to operation conditions (internal vacuum + external pressure) • … • Integration specification takes into account external dimension (including wall thickness) of the cavity as manufactured, at room temperature OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 8

Position of 2 nd beam pipe: 4 -ROD Vittorio Parma, Loren Wright

Position of 2 nd beam pipe: RF-Dipole Vittorio Parma, Loren Wright

Position of 2 nd beam pipe: QWR Vittorio Parma, Loren Wright

Cavity • Dimensions • Maximum radius external dimension (including wall thickness) at room temperature < 145 mm • Cavities dimensions to be revisited (reduced) OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 12

Cavity • RF Multipoles R. Calaga, Superconducting Technologies Workshop, Dec. 2012 OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 13

Tuning • SPS tests • Frequencies at SPS tests to be adjusted with tuner during operation (slow tuning needed only) – set only once (between 400. c and 400. d ~ 10 k. Hz) Parameter Units Frequency MHz Bandwidth Hz LHC SPS 400. 79 400. b 400. c 400. d 400 400 • Detuning (when cavity not in use) • Range of detuning required: + or - 1. 5 k. Hz ± 200 Hz • Time requirements: fast tuning (fast to be defined in more detail) OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 14

Tuning • LHC – operating frequency Parameter Units Frequency MHz Bandwidth Hz LHC SPS 400. a 400. b 400. c 400. d 400 400 • Detuning (when cavity not in use) • Range of detuning required: + or - 1. 5 k. Hz ± 200 Hz • Time requirements: fast tuning (fast to be defined in more detail) OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 15

Tuning OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 16

Tuning • Process for tuning taking into account • Deformation during manufacturing O(MHz) • Processing (hundreds k. Hz) • Cold/warm (hundreds k. Hz) • Operating conditions (< k. Hz) OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 17

Helium tank • Temperature • Operating temperature 2 K (saturated superfluid helium) • Heat losses to be evaluated in detail – dimensioning of helium tank, cryo-module and cryo-plant accordingly • Static • Dynamic • ~ 3 W / cavity • But exact and realistic value (especially for SPS tests) – important to estimate and measure OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 18

Helium tank • Helium tank to be dimensioned correctly to extract maximum heat load • Heat flux in He II depend on bath temp. and channel dimension OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 19

Helium tank • Helium tank to be dimensioned correctly to extract maximum heat load • If helium cross section expected to extract (order of magnitude) 1 W/cm 2 => detailed calculations needed OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 20

Helium tank • Interfaces • Ideally same helium tank and interfaces for all cavities – not realistic? • Standardization of interfaces for all cavities assemblies - is a very strong requirement • Choice of helium tank material (stainless steel / titanium) – strong impact on transitions: • Beam pipe (suggestion to use SS for flanges) • Cryo-module piping • HOM (and LOM) extraction, Main power coupler, OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 21 Pick-up

Helium tank • Remark: Design (cavity and helium tank) to take into account: • Interfaces for handling and transport • Interfaces for cavity processing • Interfaces for vertical tests at cold • Interfaces for alignment in cryomodule OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 22

Helium tank • Pressure • Operating helium pressure ~ 20 mbar • Pressure stability: 1 mbar • Design cavities for sensitivity to pressure fluctuation accordingly (200 Hz/mbar would be too large) • Cavity bandwidth 400 Hz => sensitivity to pressure fluctuation should be significantly lower. OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 23

Helium tank • Pressure • Maximum pressure (transients) • Safety valve set pressure 1. 8 bar • Rupture disc 2. 2 bar • Pressure equipment • All the cryo-module assembly: cavitie(s), helium tank(s), vacuum vessel – to be treated for the same risk category as the most critical one OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 24

Helium tank CERN’s safety policy regarding pressure equipment: • The general requirements for mechanical equipment during its life-cycle are defined by a specific General Safety Regulation; • A General Safety Instruction defines the requirements specific to pressure equipment; Some general requirements: • A Safety File of the equipment shall be prepared and updated by the Department; • A risk analysis shall be carried out in order to assess critical loading scenarios; • Full traceability shall be ensured from design to commissioning; The following documentation applies by order of priority: ü Internal Specific Safety Instructions ü European Union Directives European Directive 97/23/EC on the ‘Approximation of the laws of the Member States concerning pressure equipment ü Harmonised European Standards EN 13445, EN 13458, (. . . )

Helium tank The application of the European Directive for pressure equipment 97/23/EC: Covers pressure equipment with a maximum allowable pressure greater than 0. 5 bar (gauge) Defines the essential safety requirements which allow to comply with the directive & allow free movement within the EU market Front page: Directive 97/23/EC The equipment is classified into risk categories according to their stored energy and the hazard of the fluid For each risk category, modules allow to assess conformity The adoption of European Harmonised Standards ensures conformity with the requirements of the Directive Table for assessment of risk category Higher Risk Categories require the participation of Notified Bodies

Helium tank The application of the European Directive for pressure equipment 97/23/EC: o Harmonised European Standards for the design, fabrication and inspection of pressure equipment, which ensure conformity with the Directive 97/23/EC: ü EN 13445 – Unfired Pressure Vessels Part 1: General Part 2: Materials Part 3: Design Part 4: Fabrication Part 5: Inspection and testing Other parts: 6, 7, 8 & 9 ü EN 13458 - Cryogenic vessels - Static vacuum insulated vessels Part 1: Fundamental requirements Part 2: Design, Fabrication, Inspection and Testing Part 3: Operational requirements

Helium tank • Pressure equipment • Remark: All the cryo-module assembly: cavitie(s), helium tank(s), vacuum vessel – to be treated for the same risk category as the most critical one • Could be treated at CERN as special equipment: not necessity of the CE marking but same quality requirements • For 1. 8 bar pressure relieve valve => design for 1. 8*1. 43 = 2. 6 bar for cavity ext pressure, helium tank internal pressure OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 28

Helium tank • Pressure equipment – example of safety file OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 29

Helium tank • Pressure equipment – example of some manufacturing requirements for a category I equipment • Materials • All materials have to be supplied with a certification of type 3. 1 according to EN 10204: 2004 (compliance with the order and indication of test results attested by the manufacturer) • Materials covered by Harmonised European Standards automatically do comply with the requirements of PED • Remarks: • Niobium and Titanium not covered by the Harmonised European Standards • In the frame of special equipment it can be accepted on the basis of the risk analysis and of proven behavior at operating temperature OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 30

Helium tank • Pressure equipment – example of some manufacturing requirements for a category I equipment • Every weld shall be identified on manufacturing drawings and linked to an appropriate weld procedure: • Welding procedure specification (WPS) / Brazing procedure specification (BPS); • Welding procedure qualification record (WPQR)/ Brazing procedure approval record (BPAR); • Welding operators qualification /Brazer approval; • Radiographic inspection of 25% of the total circumferential seams and 100% of the total longitudinal seams. OC, 13/December/2012 LHC Crab Cavity Engineering Meeting • . . . 31

Magnetic shielding • Static magnetic field shielding required • The field to be below 1 µT at the outer surface of the cavity • Numerical simulations to determine the material thickness and specification, as well as geometry • Recommended to evaluate the effect inside and outside the helium vessel (compatible with cavity compactness requirements) OC, 13/December/2012 LHC Crab Cavity Engineering Meeting 32