ITk Strip Module Design and Performance

Abstract

The all-silicon ATLAS ITk Detector, vertexing and tracking device for the High-Luminosity LHC project, should operate at an ultimate peak instantaneous luminosity up to 7.5 × 10 34 cm −2 s −1 corresponding to approximately 200 inelastic proton-proton interactions per beam crossing. The ITk Strip Detector will consist of four barrel layers and six disks in a forward region on each side of the barrel. They will be composed of individual structures called staves and petals, whose production will require almost 18,000 single-sided strip modules of 8 different designs with the hybrid circuits carrying the front-end microelectronics ASICs glued to the sensor surface. The sensing elements are high resistivity n-in-p silicon strips capable of withstanding fluences up to 1.2×10 15 n eq /cm 2. Both irradiated and non-irradiated prototypes of strip modules undergo testing procedures including test beam campaigns supplemented by laser and beta source tests to check if they meet the design requirements of the detector.

Test beam measurement of ATLAS ITk Short Strip module at warm and cold operational temperature

“…The transistor is a switch for the application of bias voltage on the sensor. The sensor bias voltage controlled by a GaNFET transistor should not significantly exceed the value of -500 V [2].…”

“…The noise occupancy (NO) and the signed square of the threshold (𝑡 2 ) are obtained. The logarithmic relation between NO and 𝑡 2 (unit in fC 2 ) is illustrated in figures 8 and 9 for the cold and warm measurements, respectively. The plateau in figure 8 extends to negative charge, which is an artefact of the calibration [4].…”

“…In the ATLAS Inner Tracker (ITk) upgrade they are used to validate the performance of devices, such as modules, designed for the High Luminosity Upgrade of the LHC (HL-LHC). This allows key performance parameters such as hit efficiency for charged particles to be studied in detail prior to the assembly of the final detector [1] [2].…”

Production and testing of the powerboard for ATLAS ITk Strip barrel modules

“…For the High Luminosity upgrade of the LHC (HL-LHC), the ATLAS experiment [1] will replace the present SCT with the ITk Strip detector [2]. The ITk Strip detector is composed of about 18000 modules [3] in total of 60 M strip channels distributed in four layers in the barrel and six layers in each endcap, as shown in the left plot of figure 1. Two types of local support structures are used for the ITk Strip, with rectangular staves in the barrel and wedge-shaped petals in the endcap [4].…”