D0 Silicon Upgrade: Heat Transfer and Thermal Bowing Calculations of the D0 F-Diskl
Shown in Figure 1 is a side view of the D0 F-disk assembly. SVX II chips are mounted to a flex copper/kapton Circuit, which is glued to a beryllium substrate. Figure 1 shows the top and bottom disk assemblies mounted on the cooling channel. However the disks are not mounted directly opposite one another as shown, but alternately rotate through 30{sup o} wedges mounted on either side of the cooling channel. The assumed channel temperature for these calculations is 0 C, as in the cases of the ladder cooling calculations, ref. [1] and [2]. The assumed SVX II chip power is 0.400 W. The finite difference method is used to calculate the temperature profiles of the various components. It is described in Ref. [1]. Each disk is read out using SVX II chips on both sides of the silicon. The silicon is 59.2 mm wide at its widest location. The SVX II chip location opposite the cooling channel has 8 chips mounted on the hybrid. and there are 6 SVX II chips mounted outboard of the cooling channel on the same side as the cooling channel. The SVX II chips mounted on the same side as the cooling channel read out the silicon via a jumper which passes between the beryllium substrate and the cooling channel. Currently there are two substrate materials under consideration for the jumper; kapton/copper and silicon/aluminum. The two materials have different thermal properties. so both will be considered in this note in order to compare their performance in the two different assemblies. The silicon jumper is assumed to be 0.3 mm thick with a thermal conductivity of 0.15 W/mm-K. The kapton/copper flex circuit is assumed to be 0.075 mm in thickness, with 1/2 oz copper traces (a thickness of 0.017 mm copper with 0.4 W/m-K thermal conductivity) along the length. The thermal conductivity of kapton is 0.12E-3 W/mm-K [3]. The F-Disk region is occupied by cables which extend from the barrel ladders. The cables dissipate power [4] and will contribute to warming the gas. The SVX IT chips on both the disks and the ladders will also contribute to warming the gas. In addition, this region will not be perfectly insulated from the surrounding gas, which is considerably warmer than the cooling channel. The exposed cooling channels (bulkhead and disk mount channels). on the other hand, will contribute to cooling the gas in this region. The gas temperature in which the disks reside is not known due to all these uncertainties. The range of gas temperatures considered for this thermal analysis is 10-15 C [5]. Figures 3 and 4 show the expected temperature profile in the various disk assembly components during operation of the SVX II chips.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1033275
- Report Number(s):
- FERMILAB-D0-EN-456; TRN: US1200352
- Country of Publication:
- United States
- Language:
- English
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