1. PSB dump: proposal of a new design EN – STI technical meeting on Booster dumps Friday 11 May 2012 BE Auditorium Prevessin Alba SARRIÓ MARTÍNEZ

2. OUTLINE Introduction Constraints and design choices Proposal of a new design Analyses Conclusions

3. INTRODUCTION The PSB dump was designed in the 1960’s to cope with beam energies reaching 800 MeV and intensities of 10 13 protons per pulse. Over the past years, the dump encountered some problems, i.e. vacuum and water leaks. Beam energy and intensity have been periodically increased during the last upgrades. A new upgrade in beam energy (2 GeV) and beam intensity (10 14 particles per pulse) is foreseen for the near future. Consequently: a new dump is needed to cope with this last upgrade.

4. CONSTRAINTS Installation and lifetime Location Reliability Access Loading Cooling circuit Material  DESIGN CHOICES  LS1, LHC’s lifetime. The dump needs to be ready to be installed by August 2013

5. CONSTRAINTS Installation and lifetime Location Reliability Access Loading Cooling circuit Material x x

6. CONSTRAINTS Location: dimension limitations and integration  where the old dump is at present.  DESIGN CHOICES

7. CONSTRAINTS Installation and lifetime Location Reliability Access Loading Cooling circuit Material

8. CONSTRAINTS Reliability: minimise any risk of failure (avoid encountering the same problems than in the past)  DESIGN CHOICES  The design has to be as simple as possible (to maximise reliability, to reduce assembly difficulties and to ease manufacturing complexity).  Not to work under vacuum.  Mechanical connections are preferred over welding.

9. CONSTRAINTS Installation and lifetime Location Reliability Access Loading Cooling circuit Material

10. CONSTRAINTS Access: the dump core couldn’t be accessed without a major interruption in the beam availability  no in-situ maintenance can be done  redundancies must be foreseen  DESIGN CHOICES

11. CONSTRAINTS Installation and lifetime Location Reliability Access Loading Cooling circuit Material

12. CONSTRAINTS Loading ParameterUnitCurrent BeamUpgraded Beam Extraction energy E 0 GeV1.42 Peak current I* mA3088.29650.6 Average Beam Power W=E 0 *I kW626.7 1  Max. Beam Size H x V cm1.64 x 5.611.46 x 5.16 1  Min. Beam SizeH x V cm0.42 x 0.810.37 x 0.71

13. CONSTRAINTS Loading  DESIGN CHOICES  Cooling is needed to extract the almost 27 kW of average power of the future beam.  A 2 GeV proton beam requires a dump 130 cm long (when entirely made of Copper).  The diameter is defined to intercept up to 5  of the upgraded maximum beam:  = 50 cm

14. CONSTRAINTS Installation and lifetime Location Reliability Access Loading Cooling circuit Material

15. CONSTRAINTS Cooling circuit: cooling is needed to extract the almost 27 kW of average power of the future beam ▫Cooling by natural convection has been proved to be not sufficient (preliminary analyses). ▫A solution with forced air cooling is not possible either: impossibility of having a closed air loop with enough flow in this particular area of the tunnel. ▫Water cooling is mandatory to extract the almost 27 kW of average power of the future beam. ▫The minimum cooling flow is estimated at ~2m 3 /h, when water at ambient temperature is used.

16. CONSTRAINTS Cooling circuit: cooling is needed to extract the almost 27 kW of average power of the future beam  Position of the cooling pipes: close to the beam axis (maximum peak of temperature), provided that radioactive activation of water is kept within acceptable limits.  Redundancies to improve cooling reliability: 4 independent water circuits  DESIGN CHOICES

17. CONSTRAINTS Installation and lifetime Location Reliability Access Loading Cooling circuit Material

18. CONSTRAINTS Material: ▫Does not need inert atmosphere. ▫Good thermal and mechanical properties, to optimise heat extraction and to guarantee the structural behaviour of the material. ▫Materials that have a good long term performance in a radioactive environment. ▫Galvanic corrosion in between materials. ▫Erosion corrosion in pipes (max. speed of water).

19. CONSTRAINTS Choice of material: following the principle of reliability and simplicity  DESIGN CHOICES  Basic metal compounds  Thermal and mechanical properties are well known  Workability and behaviour in extreme conditions (such as ionizing radiation) is well assessed  Candidate materials: Graphite, Aluminium, Stainless Steel, Copper, Titanium

20. PROPOSAL OF A NEW DESIGN Geometry ▫Multiple-disk like geometry:  To lower the stress level  To allow natural air cooling and thermal radiation to play a role in the heat extraction from the dump

21. Aluminium keeps levels of energy deposited by the impinging beam low, while Copper helps to release the heat generated in the inner core and acts also as a shielding. Cylindrical object, two meter long and 50 cm across, with two distinct parts, one meter long each. Inner core. Disks made of Aluminium Outer core, made of Copper or Stainless Steel Structure made entirely in Copper or Stainless Steel 4 independent water circuits cool down only the first part PROPOSAL OF A NEW DESIGN

22. Elastic clamping. Regulates the stress in the water pipes PROPOSAL OF A NEW DESIGN

24. ANALYSES* to be confirmed by FLUKA -Sliced core made of Aluminium, surrounded by sliced Copper parts. -Steady State Temp reached in the core: 125°C (water cooling) -Temp in the Cu part (surrounding the Al core): remains at 22°C -Max temp in the external surface of the Al disks ~100°C

25. ANALYSES* to be confirmed by FLUKA

26. ANALYSES GeometryWater CoolingAir CoolingE escaping Aluminium core + Coppersaferisky30% Graphite core + Copper safenot safe63% Copper core + Copper safenot safe48% Titanium core + Coppernot safe- GeometryWater CoolingE escaping Latest proposal (Al + SS)safe21% Latest proposal (Al + Cu) safe20 %

27. ANALYSES

28. CONCLUSIONS The design proposed is the result of various iterations Considerable number of constraints addressed in the new design ▫Placement, logistics ▫Material and cooling ▫Reliability Future design more robust ▫Higher energies absorbed and dissipated ▫Disruption kept to a minimum

29. THANK YOU FOR YOUR ATTENTION Q & A

30. GALVANIC POTENTIALS

31. OLD PSB DUMP

34. PROPOSAL OF A NEW DESIGN Sliced core made of Aluminium, slices 4.5 cm thick, with a 5 mm gap in between them

35. PROPOSAL OF A NEW DESIGN

37. Aluminium disks, 360 mm , 45 mm thick, 5 mm gap Sliced Copper parts, surrounding the disks in Aluminium. 250 mm thick, outer  500 mm, inner  360 mm

38. PROPOSAL OF A NEW DESIGN