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For questions contact Phia at phia@stanford.edu 

Background Information

When assembling the inner tracker (ITk

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) testing is performed at each step of the way to ensure that the sensitive part of the detectors, "modules," work. When in final assembly onto the outer quarter shell the ring modules on the endcap will need to be tested to ensure no loss of functionality in the loading process. However, because of the size of the quarter shell assembly, this cannot be done in a cooling chamber so these tests will be done without coolant. A big concern here is the heat output of the modules raising the temperature past the safe temperature range for the modules

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. 

The current solution is to do the testing in low power mode where most of the functionality, but not all, can be checked. To test the feasibility of this proposal, a mock ring with dummy heaters to simulate the power from the modules is used to test the heat output. The

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heat output across the ring can be read via 'RTDs,' or resistance temperature detectors. 

Additionally, on each ring, there is an outer type 0 or ``rigid" ring that provides power to the ring but traps heat and limits external cooling. In this test, due to practical limitations of the availability of a metal type-0 ring, a plastic 3D-printed type-0 ring is used instead

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. The difference in thermal properties must be

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acknowledged when interpreting the results.

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Additionally, due to the height of the RTDs on the heaters, the ring is placed further from the heaters, at a height of 0.17 inches rather than the planned 2.4 mm (0.094 in). 

Terms

RTD = resistance temperature detector

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Images: The smaller fan used (left) and the larger fan (right) are shown in the same position relative to the ring. 

RTD Position

The position of the modules or dummy heaters can be found on the confluence webpage Dummy Heaters. The 'T' or 'S' denotes triplets or single modules at the inner ring 'L0' whereas the 'Q' denotes the quad modules at 'L1.' The 'U' is to indicate the cooling tubes up position and the 'D' for cooling tubes down. 

 Powering:

The modules, as well as the heaters, are powered serially in 'serial power' (SP) chains with L0 separate from L1 and the up and down sides of the ring separate as well. This is done to reduce the nonsensitive material within the detector. When doing the low-power testing, while it would take longer, it is possible to separate each side L0 and L1 to reduce the heat at any given time.

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