by Alberto Gago Medina. Published: 28 June 2015

PUCP ( Pontificia Universidad Católica del Perú) team joined ALICE in 2004. This was initiated by an invitation from Prof. Gerardo Herrera who asked me to help the Mexican group on the validation of the design of the V0A detector. Since then, the PUCP team has made different contributions to ALICE. Among them are the development of the analysis techniques, the study of the detector’s performance, its design and many more. For instance, we have been heavily involved in the software studies of the design, the performance as well as the data acquisition system of the ALICE diffractive (AD) detector: a project of the new ALICE subsystem that initiated years ago. In fact, we are still working on the AD detector.

In this way, up to now, our contributions focused on the side of software simulation but not on the hardware side. However, the latter situation has already changed since we are engaged in the hardware development project of the ALICE Muon Forward Tracker (MFT). In order to put our work in context, we should first discuss an overview of the MFT detector.

The MFT is a Si-tracking detector and part of the ALICE upgrade programme planned to be working after the Second Long Shutdown (LS2) in 2019. Its main goal is to enhance the capabilities of vertexing and tracking in the muon spectrometer. The physics goals are to study the production of open heavy flavours (charm and beauty), quarkonia and the low mass dimuons spectra in the ALICE forward rapidity region. By means of these studies we will be more sensitive to the density, the temperature and the dynamical properties of the matter produced in the heavy-ion collisions. The MFT detector technology relies on CMOS Monolithic Active Pixel Sensors (MAPS), a chip technology that combines the active semiconductor sensor and the front-end readout electronics in a single device. This type of chip fulfills all the MFT requirements regarding material thickness, granularity, power consumption, and radiation hardness.

The first commitment of the PUCP team as part of the MFT project is to contribute to the characterization tests of the MFT´ MAPS. For the MFT the pALPIDE (prototype ALICE Pixel Detector) chip has been chosen; a chip which measures 15.3 mm by 30 mm and is formed by a matrix of 512 x 1024 pixels. The characterization tests that are going to be performed at the PUCP HEP-lab comprise the illumination of the chip with radioactive sources and infrared laser light, the study of its temperature dependence (T-dependence) and the radiation damage which is simulated by irradiating the chips with a neutron source. In the PUCP HEP-lab, we have already implemented the basic setup for testing the chip, i.e. we have the sensor on a chip carrier card linked to the data acquisition card, which is then connected to the computer and the software needed for communicating with the chip.

So far, we have made several of the basic tests and are waiting for the arrival of the radioactive sources and the chiller for the T-dependence studies. The tests using infrared laser light and neutron irradiation deserve a special comment, since they are implying interplay between our HEP-lab and other institutes. They are the applied optical lab of our university, for the infrared laser light test, and the IPEN (Peruvian Institute for Nuclear Energy), for the neutron irradiation test. We had meetings with physicists from IPEN in order to discuss the technical details related to the chip irradiation using its nuclear reactor as well as with physicists from the lab of applied optics. It is very encouraging to see the willingness of local scientists from different areas to help us getting into the R&D effort of a high energy physics experiment. If we are able to establish these collaborations, in the context of our responsibilities on the MFT hardware, we could effectively show in Peru how the development of a high-energy physics experiment is connected with the development of a variety of different technologies. This would help us a lot in the assessment of the importance of doing basic science, particularly HEP, within the scale of the Peruvian research priorities.

Finally, it is worth mentioning that this represents only the beginning of our hardware responsibilities in the MFT project, since we are also going to work on the next steps of the development of the MFT project pointing to the assembly of the full detector. The PUCP–team is composed of a postdoc, Eric Endress, a tenure track, José Luis Bazo, a PhD student, Ernesto Calvo, an electronics engineer, Angela Sánchez, and myself. We expect to enlarge the group very soon.