HRM 28 Update 12/05/2016 F.L. Maciariello, F.-X. Nuiry, M. Butcher, K. Karagiannis, V. Kain, L. Mircea, M. Calviani, O. Aberle, S. Burger, T. Lefevre, C. Bracco, A. Sounas, G. Trad.

The High Radiation to Matertials Test-Bench Graphite 2123 PT (Mersen) C/C A412 (Mersen) Particle Beam Graphite Sigrafine® R4550 (SGL) Sepcarb® 3D C/C (Safran-Herakles)

[7-04-2016] Measurements of the beam spot size + location (X and Y): BTV: Ok for 1 bunch nominal, problems in getting images with 12 bunches, BSRT, Ok, BPKG, Ok. The beam location was rather stable within the expected jitter of +/-0.15 mm. Set-up phase for the graphite jaws: Beam based alignment (1 bunch nominal, no BLM saturation), Graphite SGL jaw located at 1.5 sigma impact parameter. Vibrometer alignment: Horizontally scanning the beam with the 5th axis and looking for the strongest displacement signal on the vibrometer. During this phase  issues with the DAQ system (crashed few times) as well as the trigger (sometimes not seen by the DAQ).

Vibrometer Live Alignment X Beam Scan Direction Y Beam Position Theoretical Beam Initial Position of the Vivrometer = Theoretical Beam Real Beam In order to find the maximum displacements signal, a beam scan with the vibrometer was performed 8 9 6 11 1 2 4

High intensity shots on the SGL Graphite: Graphite jaw was impacted 2 times with 288 bunches beam, recorded with the HD and Radhard camera before and after each shot (internal cameras didn’t transmit any images even if they still have power). The DAQ system crashed both times, so no signal response from the vibrometer. 1 sigma impact parameter confirmed (Chiara). High intensity shots on Mersen Graphite: Positioning the jaw on 1.5 sigma impact parameter and impacting two times with 288 bunches beam. 3rd high intensity shot on SGL Graphite: In order to try to record data from the vibrometer a 3rd high density shot on SGL Graphite was done. The jaw was placed on 1.5 sigma impact parameter and it was impacted with a 288 bunches beam. The DAQ worked.

HRM28 Results 288 Bunches Impact 12 Bunches Impacts The results showed an outstanding agreement between the experimental measurements and the simulations The displacements increase linearly during the phase of load application (the beam pulse length lasts about 7.8 μs), then the surface smoothly tends to reach its initial position through small oscillations of about one micrometer of maximum amplitude 12 Bunches Impacts Exceptional repetitiveness of the results was also noticed

Strain Rate Behavior Dependency Before After No visual damages on the graphite The tensile limit of the graphite is higher with dynamic loads (strain rate: 5×102 s-1) than with static ones (strain rate: 0.5×10-4 s-1) [2]   Sigrafine® R4550 Max. temperature [ ̊C] 1348 Max. Principal Stress/ Tensile Strength [MPa] 40.1/30 Min. Principal Stress/Compressive Strength [MPa] -80/-118 Mohr-Coulomb Safety Factor 0.72 [2] “Investigation of Dynamic Fracture Behaviour of Graphite” Lorenzo Peroni, Martina Scapin, Federico Carra, Nicola Mariani, Departement of Mechanical and Aerospace Engineering, Politecnico di Torino and CERN, Geneva Switzerland

Low Intensity Shots (12 bunches) Pulse Beam Location (BPKG) H[mm] x V[mm] 1 0.14 x 0.26 2 0.21 x 0.31 3 0.20 x 0.29 4 0.18 x 0.26 5 0.18 x 0.25 6 0.18 x 0.22 7 0.15 x 0.22 8 9 0.16 x 0.25 10 0.18 x 0.18 11 0.17 x 0.25 12 0.13 x 0.21 The beam location was rather stable within the expected jitter of +/-0.15 mm

High Intensity Shots (288 bunches) Pulse Intensity Beam Location (BPKG) H[mm] x V[mm] Beam Spot Size (BSRT) σx X σy [mm x mm] 1 3.235 E13 0.28 x 0.21 0.47 x 0.37 2 3.213 E13 0.28 x 0.23 0.44 x 0.38 3 3.263 E13 0.27 x 0.23 0.43 x 0.37 4 3.229 E13 0.26 x 0.21 0.45 x 0.37 5 3.178 E13 0.34 x 0.27 0.43 x 0.36 Suggested action: run a new simulation with the parameters measured

Actions taken so far [8-04-2016] Set-up phase for the 3D C/C jaws: Beam based alignment done. Few single bunch nominal intensity pulses needed before restarting (to check the beam location). Vibrometer alignment: Horizontally scanning the beam with the 5th axis and looking for the strongest displacement signal on the vibrometer. Not completed yet, we need to scan the jaw on the other direction as well.

Next actions … Vibrometer alignment: Vibrometer alignment on Herakles 3D C/C jaw with 12 bunches beam. High intensity shots on Herakles 3D C/C: Positioning the jaw on 1.5 sigma impact parameter and impacting two times with 288 bunches beam. Take pictures of the jaws before and after the shots. High intensity shots on Mersen 3D C/C: Positioning the jaw on 1.5 sigma impact parameter and impacting two times with 288 bunches beam.

!!! Thank You !!!