Ge 31/10/03. First thermal measurements on modules on stave. M.Dameri, F.Vernocchi et al. (R. Cereseto, G.Gariano, C.Gemme, M. Parodi, C. Pizzorno, L.Rossi, A.Rovani, E.Ruscino). 3 FEI1 modules: 20210020420058 in position 3, power: 3.3W (chip7 off, chip8 malfunctioning)
M.Dameri, F.Vernocchi et al. (R. Cereseto, G.Gariano, C.Gemme, M. Parodi, C. Pizzorno, L.Rossi, A.Rovani, E.Ruscino)
3 FEI1 modules:
20210020420058 in position 3, power: 3.3W (chip7 off, chip8 malfunctioning)
20210020420026 in position 4, power: 2.4W (chip14 off)
20210020420023 in position 11, power: 2.5W (chip 8&13 off)
have been mounted on a prototype stave with the production machine and procedure.
Thermal images have been taken with the module fully configured and with a power consumption as detailed above. Cooling was done circulating fluid at ~10C in a room temperature environment.
20210020420023 no power
High digital current on pigtail
20210020420023 power on
20210020420026 no power
20210020420026 power on
20210020420058 no power
20210020420058 power on
Glue thickness has then been measured with a microscope, looking at the module cross section, as shown:
Glue layer is not uniform and the temperature on NTC (on chip 14 toward the module center) feels this. The glue layer thickness does not appear to be very critical (~1 C per 10W), unless we go above 200mm.
We do not observe local hot spots indicating that the silicon and C-C heat transmission coefficient smears out local effects.
Geometrical position has been checked, measuring the edge of the pads on the FE chips (reference crosses are not visible in those modules) in positions A and B:
The lateral displacement relative to the stave reference system are:
20210020420058: A=-20mm, B= 0 mm
20210020420026 A= 0mm, B= 10 mm
20210020420023 A=-40mm, B=-100 mm
All measurements indicate a problem in the placement of module 20210020420023