SVT Mechanics & Beam Pipe F. Bosi - M. Massa INFN-Pisa on behalf of the SuperB-SVT Group XI SuperB Workshop - Frascati, December 1-5, 2009 SuperB Workshop IX - Perugia, June 16-20, 2009

Outline SVT Mechanics Beam Pipe Work planning Full micro-channel pixel module Net micro-channel pixel module Beam Pipe Requirements and general considerations Conductive thermal study Radiation length Hydraulics and convective cooling Structural studies Work planning SuperB Workshop IX - Perugia, June 16-20, 2009

Full pixel module support CFRP MICROCHANNEL Obtained with additive method, gluing side by side single microtube. The hydraulic diameter of the unit microtube is 300 mm, the square thickness is 700 mm . 700 mm 700 mm Spread microchannel components before assembling Carbon Fiber Poltrusion CFRP Module Support assembled The total radiation length of this kind of module is about 0.28 % X0. An internal peek tubes 50 mm thick, is used to avoid moisture. SuperB Workshop IX - Perugia, June 16-20, 2009 3

Full pixel module Test Results tests results performed on to N°2 sample for both micro-channel and tri-channel modules. Tm=32.9°C Tm=35.9°C Module Temperature average vs Specific Power for single side Module Temperature average vs Specific Power for double side SuperB Workshop IX - Perugia, June 16-20, 2009 4

Full pixel module test results Cooling test results for microchannel (sensor at 30-35 °C with 2 w/cm2) matches the thermal specifications ! Thermal-hydraulic test , conducted on several module prototipes, comfirms this results . SuperB Workshop IX - Perugia, June 16-20, 2009 5

Net pixel Module Net Module is a micro-channel support with vacancy of tubes in the structure, accepting worst cooling performance but with strongly gain in X0 Net Microchannel Module Support Material of the support structure: ( CFRP + peek tube + Water + CFRP Stiffeners ) SuperB Workshop IX - Perugia, June 16-20, 2009 6

Construction Activities Net Micro-channel Module Support realized with a special gluing Mask. Module dimensions : width 12.8 mm, length 125 mm. Gluing operation with epoxy is partially performed on the mask then completed out the mask under microscope

Net pixel modules support 125 mm First Prototype produced ! Net module mechanical structure: 10 microtube + 5 trasversal comb Thermal simulation under study……..

Net pixel module support Trasversal comb geometry , th=0.5mm 1.5 mm Comb obtained by micromilling machine tooling 0.75 mm 0.6 mm 0.75 mm

Net pixel module support Epoxy glue used to fix microtube to trasversal comb . Very complicated micropositioning and microgluing work on the positioning and gluing mask!. Sealing in the hydraulic interface obtained still with epoxy. C = 0.17 % C0

Beam Pipe/Requirements For preliminary studies we consider a monolithic beam pipe with internal diameter 20 mm, th=1mm and a length of 100 mm. The material is beryllium with thermal conductivity of 216 W/mK. The total power consumption is 200 W; that means a power density (Total power/Internal surface) of 3.18 W/cm2 The request specification is to have Tmax is: Tmax < 35 °C (same sensor temperature coming from TFD test). SuperB Workshop IX - Perugia, June 16-20, 2009

Beam Pipe/Conductive Study Considering a steady-state conduction the Tmax will not satisfy the thermal requirements. In this simulation the two external transversal cross section (cold ring) have a fixed temperature of 10 °C. Heat transfer mode: steady-state conduction Material: Beryllium, th=1 mm Thermal conductivity: 216 W/mK Total Power: 200 W (3,18 W/cm2) Beam Length: 100 mm Temperature boundary condition: 10 °C on the external cross sections (cold rings). Tmax = 185.5 °C SuperB Workshop IX - Perugia, June 16-20, 2009

Beam Pipe/General Considerations In order to satisfy the thermal requirements we followed this convective cooling design. Geometry under study for the beam pipe : Legenda: Green: External Pipe Red: Internal Pipe with pillars Bleu: Micro-channels Di=20mm THext: Thickness of external cylinder THcool: Thickness of micro-channel THint: Thickness of internal cylinder The beam pipe is build with two beryllium concentric cylinders with 4 pillars in order to have four micro-channels with coolant .Beam pipe length= 150 mm . SuperB Workshop IX - Perugia, June 16-20, 2009

Beam Pipe/Radiation Length We studies two beam pipe configurations. The shared characteristic is the beam pipe assembled with two cylinders and four micro-channels (see previous slide). The differences between the two configurations are the thickness of the pipes and of the micro-channels. ITEM UPPER LIMIT LOWER LIMIT Thickness (mm) External Pipe 0.3 0.4 Internal Pipe Micro-channel (Water included) 0.2 Considering a transversal cross section the total radiation length is: UPPER LIMIT LOWER LIMIT % Co 0.23 + 0.12 = 0.35 0.32 + 0.12 = 0.44 REMARKS: The value “0.12” is due to the 4 mm layer of gold (common to the two configurations). (still to be included epoxy coating contribution on the beryllium surfaces in contact with coolant) SuperB Workshop IX - Perugia, June 16-20, 2009

Beam Pipe/Hydraulics Studies For both configurations we have analyzed the hydraulic and the thermal behaviors, considering water as coolant and imposing 2 °C as longitudinal thermal gradient (temperature difference between input and output ) we found this characteristics : UPPER LIMIT Channel thickness: 0.2 mm LOWER LIMIT Channel thickness: 0.3 mm Hydraulic diameter 0.394 mm 0.578 mm Flow per row(*) 0.358 kg/min Reynolds number 865 846.5 Fluid velocity 2.2 m/sec 1.44 m/sec Distributed pressure losses 0.67 atm 0.2 atm Nusselt number 5.25 5.122 Average film coefficient 7193 W/m2K 4711 W/m2K (*): The flow per row is the same for the two cases because they have same specific power, same longitudinal gradient and same specific heat and the definition is: SuperB Workshop IX - Perugia, June 16-20, 2009

Beam Pipe/Convective Studies/1 The inputs and the boundaries conditions are: Power density: 2.12W/cm2 Coolant: Water Film Coefficient: Material: Beryllium 7193 W/m2K for the inferior limit Thermal Conductivity: 216 W/mK 4711W/m2K for the superior limit Longitudinal thermal gradient between input and output: 2 °C Coolant temperature: 10 °C The results are: Lower limit Upper limit 12.7 °C 13.8 °C REMARKS: In order to simplify the convective calculus we have a typical transversal cross section. SuperB Workshop IX - Perugia, June 16-20, 2009

BP/Convective Studies/2 Upper limit – Internal Pipe Lower limit – Internal Pipe 12.7 °C 13.8 °C SuperB Workshop IX - Perugia, June 16-20, 2009

BP/Convective Studies/3 Upper limit – External Pipe Lower limit – External Pipe 12.1 °C 12.8 °C SuperB Workshop IX - Perugia, June 16-20, 2009

Beam Pipe/Structural Studies For the structural studies we have focused our attention to the upper limit layout (beam pipe thickness 0.3mm) . The internal beryllium beam pipe is a pressure vessel loaded with an atmospheric pressure due to the vacuum and to the pressure due to the the coolant inside the micro-channels (total value about 1.7 Atm.) Assuming for the calculus a pressure value of 5 Bar means take about a security factor of 3. The stress on the beam pipe calculated with elastic criteria results: Longitudinal stress: 0.874 kg/mm2 Circumferential stress: 1.748 kg/mm2 ( Very far from the work tension of the beryllium material ! ) SuperB Workshop IX - Perugia, June 16-20, 2009

Beam Pipe/Structural Studies For what concern the elastic instability of the internal beam pipe, a typical failure criteria of thin cylinders is buckling .( Cylinder is thin when the ratio between the thickness and the external diameter is  0.1). For beam-pipe geometry, we evaluate the value of the critical buckling pressure with the Von Mises* relation and found : Pcr ≈ 20 atm (critical pressure ) We found this result using a length of 200 mm) (adding a new safety factor in length respect the 150 mm assumed in thermal hydraulic study and considering as a reinforcements an annular brazing ring Be-SS ). *correction also with Windenburg and Trilling criteria

BP/Structural Studies Studies with no defects are not realistic , for this purpose let’s introduce the terms “” . ( is the deviation from the radius value of ideal cylinder, in other terms is the eccentricity value of radius beam pipe) If, for construction problems, we assume  = 0.5 mm, the critical pressure caused by buckling is: goes down fr 20 atm to 5 atm. Pcr- ≈ 5 atm (critical pressure for geometry ) We are taking contact with brush -Wellman company in order to verify technological and manufacturing problem for the beam pipe dimensions . SuperB Workshop IX - Perugia, June 16-20, 2009

Future Works/ Conclusions Next work on the Net pixel micro-channel support are thermal and hydraulic test at the TFD lab in Pisa , as the ones performed for the full micro-channel module, in order to validate cooling temperature conditions . For the beam pipe design we want made an aluminum model for the inner central skin. The idea is to test structural and thermal dimensioning for aluminum material and translate then the results on the Beryllium material . Design of central skin of beam-pipe need to be integrated with transition part Be- SS, brazed joint, cooling beam pipe lines and cooled manifold flanges for L0 support .