High Energy Dump of the Super Proton Synchrotron at CERN – Present and Future designs A. Perillo-Marcone (EN-STI) Contributions from several colleagues from EN/STI, EN/MME, EN/HE, EN/ACE.

SPS/Dump Layout 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone22 Current Dump position Future Dump position

Current Dump – TIDVG (to be replaced during LS2 by the dump presented here) 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone33 Iron Shielding (EN-GJL-200) Copper Core – 4.3 m (OFE, C10100 H02) Graphite – 2700 mm (2020 PT) Aluminium – 800 mm (EN AW 6082 T6) Copper – 500 mm (OFE, C10100 H02) Tungsten – 300 mm (Densimet 180) Beam Beam opening Copper core (Envelope+blocks) Shielding Section A-A Section B-B Cooling circuit for copper core Cooling pipes for shielding B B A A

Previous dump failure 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone44 TIDVG 1 ( )TIDVG 2 ( ) Aluminum block after operation

Operating limits imposed by current design (applied only after LS1) 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone55 Beam Beam Power (kW) Number of pulses accepted Max. T in Aluminium (°C) Cooling time to 35 °C (min) LHC-Standard (25 ns) LHC-50 ns57.7unlimited12121 Doublet62.3unlimited18329 FT 100%178.03x3 (40s spacing)20524 LHC-Std. – FT 100%62.5unlimited25046 The interlock has been set so that if more than 3.66E13 protons are dumped within a sliding time window of 36s, then a waiting time of 70s is enforced.

Operation of Current Dump 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone66 Good agreement for total power transfer as shown by water pipe measurements. Also good agreement in primary shielding Observable difference for temperature in Copper jacket around Al section. This indicates a lower TCC than anticipated, implying the possibility of higher temperatures in the Al section Possible explanation: flatness defects of copper jacket surfaces To be verified with higher intensity beams and if necessary re-set limits Water temperature Cu core temperature

Aspects of current design to be improved 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone77 Graphite installed before welding Cu core (long time exposed to air and other possible contaminants). High outgassing rates. No proper bake-out possibilities after installation. No internal instrumentation (blind during operation). Only visual inspection possible (limited by high radioactivity). Aluminium as beam-absorbing material. Poor performance at high temperature, low melting point, resulting in limited operation. High uncertainty, unreliability of cooling efficiency due to unpredictable thermal contact between blocks and Cu core. Limited choice of suppliers due to design.

New Design Proposal 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone8 Primary shielding (cast iron) (5m long x ~1m diameter) Core (Copper) (5m long x ~300mm diameter) Graphite (4300 m) Copper (400mm) Tungsten (300mm)

Dump Core + Primary Shielding 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone9 < 22 t 850

Dump Core - Current Design 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone10 EB Welding 4 sub-parts welded Material: OFE copper 2500mm

Dump core cooling – preliminary design 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone11 Cooling channels Absorbing block Compression Spring Cooling plate CuNi pipe Brazed to Glidcop plate

Preliminary Thermo-mechanical Analysis 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone12 Graphite Temperature MaterialMax. Temp ( o C) Stress (MPa) Strength (MPa) Graphite Copper192230>300 Tungsten 67143>500

Improvements, advantages over TIDVG 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone13 Improved cooling of absorbing blocks. Decoupling of cooling and positioning of absorbing blocks. Possibility to insert/extract absorbing blocks after manufacturing of Cu core Temperature measurements of absorbing blocks, Cu core and primary shielding. Integrated bake-out system for dump core. Smaller, more manageable parts (more suppliers for Cu core). External shielding (personnel protection). Better shower attenuation (machine protection). More accurate positioning/alignment.

Feasibility, open questions 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone14 Open questionsIssuesActions/Future studies Thermal contact effectiveness between absorbing blocks and cooling plates TCC test bench Prototype Feasibility of cooling plate – cooling pipe assembly. Cooling pipe supply Bending Research of suppliers. Prototype Design optimisation Robustness, inspectability, reliability of welds. Risk of leaksPrototype Design to allow NDT of all welds. Erosion-corrosion in cooling system. Risk of long term leaksMinimise water velocity. Erosion/corrosion tests for OFE-Cu. Material selection to prevent this issue. Long term performance (20-30 years) of materials and welds under irradiation. Embrittlement => cracks => leaks. Relaxation of springs cooling plates Literature research previous/ongoing studies. Selection of materials. Long term of temperature sensors and bake-out system. Loss of monitoring in long term Collect data and analyse it from early stages of operation.

Prototype 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone15 500mm

Schedule (main milestones) 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone16

Thank you for your attention.

Back-up slides 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone18

External Shielding Dump Core Proposed Design for future dump 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone19 Primary Shielding Supports (jacks) Alignment rods Vacuum chamber Mushroom for remote handling

Full assembly 6th April 2016SPS High Energy Dump Design - A. Perillo-Marcone20