by Virginia Greco. Published: 18 December 2017

Salvatore Aiola is a Ph.D. student at the University of Yale, US, but he is now based at CERN, where he is completing his thesis. He has recently done his first shift as ALICE Run Manager.

The first time Salvatore Aiola came in contact with ALICE was during his Bachelor’s studies, as he recounts. His end-of-course project was on an cosmic-ray experiment, but the group of the University of Catania where he was studying was also involved in ALICE, so he got to learn about it. Then, during the summer of his first year of Master’s, he participated in the CERN summer student programme: in that occasion, he was chosen to work on the electromagnetic calorimeter (EMCal) of ALICE within the group of the Lawrence Berkeley National Lab. In particular, he studied the trigger for the Pb-Pb run of the end of 2011 and also made his first steps in the analysis of jets.

Once he completed his Master’s exams, he went back to CERN for five months, where he continued the analysis of the jets in Pb-Pb collisions, using the data collected in 2011 at 2.76 TeV. “It was an important measurement,” Salvatore explains, “since it was performed including the information given by the EMCal, while previous studies had been carried out using only the data from the TPC, thus considering only charged particle tracks. The complexity of this analysis is due, in particular, to the presence of a significant background coming from the production of soft particles.” He also had the occasion to present his work at the Hot Quarks Conference in Puerto Rico, in October 2012, just before receiving his Master’s degree in November.

In the meanwhile, he had started to collaborate with the ALICE group of the University of Yale, so John Harris – currently the chair of the Collaboration Board of ALICE and professor at this prestigious institution – proposed him to enter the Ph.D. programme at Yale and join his group. Attracted by this perspective, Salvatore applied to the programme and he received a positive answer in April, so he could start in the 2013 fall semester.

During the first two years he had to attend courses - four per semester - and also to give laboratory classes to undergraduates. “The first year was quite hard, because I had to settle down there, make new friends, study and, on top of that, prepare and give lessons,” comments Salvatore. “Of course, I had to put into pause my research activities. During the second year I could gradually start again to work on analysis.”

Overall, he spent four years at Yale, where he studied jets that include D mesons. It is an analysis in which D mesons are used to tag jets that come from the fragmentation of a charm quark. “Being part of the group of John Harris and his students has been a fortunate opportunity and I have enjoyed it a lot!” he highlights. “In addition,” he continues, “I appreciated that, since they are involved in the STAR experiment at RHIC as well, interactions and exchange of ideas between colleagues working in these two different heavy-ion experiments were quite frequent”.

According to Salvatore, the little town of New Haven, where the University of Yale sits, has not much to offer, while on the contrary the campus is scientifically and culturally very alive. “The University has very good facilities, many laboratories, libraries and rooms for studying,” he explains, “and it has a big school of theatre and music, so there are always cultural activities going on.”

Salvatore is now spending his last year of Ph.D. at CERN because, at this stage of his thesis work, it is particularly fruitful to collaborate closely with the other researchers and Ph.D. students working on the same analysis. “It is certainly easier to interact and progress if you are not 6 time-zones apart and, even better, if you have the possibility to work side by side,” he notes.

This year in October Salvatore was Run Manager of the experiment for the first time, an experience that he really enjoyed. “Spending so much time in the ALICE control room,” he explains, “I had the opportunity to interact with many colleagues that work on the detector, the trigger and the data acquisition system. This allowed me to get a deeper knowledge of the hardware and to be inspired by the experts who are very passionate about it.”

Even though his main activity is data analysis, he might decide to dedicate some time to hardware development in the future. He had a first experience with that at Yale, where he helped out with the study of a possible configuration for the upgraded TPC. They tested a prototype including two GEM chambers and one Micromegas, which gave results similar to those of the four GEM solution, but the latter setup was finally chosen because it had been studied more in depth.

“An important duty of the run manager is to organize the data taking activities as well as interventions, if access to the cavern is allowed,” Salvatore explains. “This means preparing schedules, contacting people, interacting with the radioprotection experts, etc. These are activities that I do not normally perform, my workday is in general made of hours sitting alone in front of my computer, analysing data. Being the run manager, I realized I have skills that I didn’t know I had.”

According to Salvatore, the most important thing for a run manager is to have a global view of the data taking process: “I had been shift leader in the past, but in that role you make your eight-hour shift and then go home, while when you are the run manager you need to keep an eye on the system even when you are not in the control room. In addition, you interact with the three shift crews that rotate at the ‘pilot house’ of the experiment and you need to make sure that they apply the right procedures and that everything runs smoothly.”

After this experience, Salvatore might consider the possibility of taking an active role in the control room. “I think that being system run coordinator, for example, can be very interesting. Of course, it would imply leaving data analysis aside for some time, since it is a job that requires full dedication to your detector or system. It means spending a lot of time in the control room, understanding very well your piece of detector, learning its inefficiencies and working hard to reduce them. The development never stops, because you can always improve the efficiency and make the system work better.” Of course, this is not exclusive responsibility of the system run coordinator, since every detector or system has a team of experts working on it. Nevertheless, a person who is fully dedicated and keeps track of problems and inefficiencies, as well as changes and development, can guarantee the best results.

Once he has finished his Ph.D., Salvatore will look for a postdoc, possibly to keep working at CERN in ALICE. Besides doing research, he would be happy to have the occasion to teach as well. “I hope I will be able to continue working in ALICE,” he admits, “I am fascinated by the kind of physics we study. In particular, I am intrigued by the fact that the quark-gluon plasma is a very tiny object, which exists for an extremely short time, so short that we cannot detect it directly, but only the products of its cooling down and hadronization process. It is incredible that we can get to discover and learn so much about such an exotic physics object. You need a lot of imagination even to think of it.”

While working to finish his PhD thesis, Salvatore is also planning his wedding, which will take place in Italy next April. Therefore, he is very busy and doesn’t have time for extra activities.  Nevertheless, when he can, he goes biking and cooks: “I love cooking, I did it a lot when I was in the US, because there I learned quickly that, in order to eat as I like, I needed to cook myself.”