Disputation: Sohail Musa Mahmood

Doctoral candidate Sohail Musa Mahmood at the Department of Physics, Faculty of Mathematics and Natural Sciences, is defending the thesis 

“Exploring Single Event Effects in the ALICE (A Large Ion Collider Experiment) SAMPA chip”

for the degree of Philosophiae Doctor.

portrait of the candidate

The PhD defence and trial lecture are fully digital and streamed using Zoom.  The chair of the defence will moderate the disputation.

Ex auditorio questions: the chair of the defence will invite the audience to ask ex auditorio questions either written or oral. This can be requested by clicking 'Participants' and then choose 'Raise hand'. 


Trial lecture

“High-energy nuclear physics with future heavy-ion and electron-ion colliders”



Main research findings

After the second long shutdown (LS2) ending in 2021 at the Large Hadron Collider (LHC), improved resolution requirements of the tracking detectors in the High Energy Physics (HEP) experiments demand a higher number of readout channels and more compact front-end electronics. In this context, the "SAMPA" chip is developed to fulfill the readout requirements for multiple detectors at the ALICE (A Large Ion Collider Experiment) experiment. As the SAMPA chip is fabricated in a commercial Complementary Metal Oxide Semiconductor (CMOS) technology, the radiation hardness assurance of the chip was imperative for ensuring its reliable and acceptable operation in the ALICE radiation environment. This is accomplished by conducting high-energy protons, heavy-ions, and pulsed-laser irradiation campaigns on various prototypes of the SAMPA chip.
During protons exposure of second prototype, destructive single event latch-up (SEL) events were detected. Dedicated collimator tests with the heavy-ions and pulsed-laser tests were conducted to identify the primary source for triggering SEL events. Consequently, the SEL sensitive circuits were replaced in the final SAMPA version and another heavy-ions campaign was conducted to confirm their robustness against SEL events. Conclusively, the final version of the SAMPA chip is expected to operate reliably in the ALICE radiation environment.

SAMPA in beam during protons exposure
SAMPA in beam during protons exposure


Contact information to Department: Line Trosterud Resvold

Published Nov. 19, 2020 11:18 AM - Last modified Dec. 5, 2020 2:48 PM