by Virginia Greco. Published: 18 December 2017

An idea of the Junior group of the ALICE collaboration, the Hackathon events are aimed at sharing ideas and sitting together to develop some useful IT tools over one evening. The third appointment, held last November, embraced a different kind of challenge: developing some outreach material.

A screenshot of the ALICE data-taking statistics page created by the ALICE Juniors.


During the last collaboration meeting held in November, the third edition of the ALICE Juniors’ Hackathon took place. This is one of the many activities carried out by the Junior group -  which includes students as well as young researchers who have received their university degree in the past eight years or their PhD in the past five years.

The idea of tackling practical problems in a Hackathon event and developing some useful tools occurred to Mike Sas and was supported by other juniors. Among them was Christian Bourjau, who took responsibility for organizing the first Hackathon evening in March 2017. Its objective was to realize a basic home page summarizing some of the statistics of the data taken by ALICE over the years and allowing users to retrieve easily information about any specific data sample.

One evening was not sufficient to finalize the project, but the structure of the webpage was put in place. With some additional work, it led to the nice ALICE data-taking statistics page.

A few months later, a second Hackathon event was held by the ALICE Juniors, this time around the idea of encouraging the production of “clean” analysis code and of developing a sort of testing system for it. In order to perform their data analysis, physicists in ALICE write pieces of software in ROOT and run them on samples of data. It is common to have programs made of bits of other pieces of code and full of patches: they work and produce the required results, but are not written in the best possible form. Restructuring this analysis software takes some time, but later on makes one’s work easier and faster. Rewriting some code that works, though, implies the risk of introducing errors and breaking it or altering the analysis. Therefore, it would be very useful to have a tool that runs the original “dirty” code and the clean one with the same sample of data and compares the output files produced to check that results do not change. A group of Juniors tried to develop such a tool, but it was too long a project to be even shaped in just one evening. Thus, unfortunately, they didn’t converge on a final product. Nevertheless, the exercise was interesting and the issue might be addressed again in the future.

The latest Hackathon appointment was dedicated to a quite different topic. The members of the Junior group discussed recently about getting more involved in outreach and educational activities and the November Hackathon looked like a perfect occasion to develop a project in this field.  The original idea was to produce some educational software for the Masterclasses, but they realised soon that it was an objective too ambitious for a few people working one evening. Thus, after brainstorming on possible alternatives, they decided to work on designing a poster about ALICE and heavy-ion physics aimed at the general public, not only adults but youngsters (over ten years) as well.

They focused on finding analogies and comparisons that would give the sense of the time and length scales with which particle physicists, and in particular ALICE’s, work. Statements like "if a nucleus were the size of the thickness of a hair, the ALICE detector would be as big as the solar system", as just an example, are very effective because they amaze non-experts and help them to grasp concepts with which they are not familiar. Hopefully, they can also inspire kids and teenagers, who might decide to study science.

Once the participants identified some of these catchy concepts and comparisons, they started the design of the poster. One evening of work proved again not to be enough to complete the project, but it was left well on track and will soon be finalised.

Since the idea of hosting Hackathon events seemed successful, a new challenge will be thrown as well at the next Collaboration meeting, in March 2018. Stay tuned!