Data collected over a two-day period in June 2024 at the CERN SPS H9 test beam using a small-scale GRAiNITA prototype have been analyzed to characterize the detector's energy resolution performance. The measurements allow for a first estimate of the constant term associated with detector non-uniformity. Although the evaluation is limited by the small prototype size and the use of pion beams, the results indicate that the non-uniformity-related constant term is significantly below 1%. Furthermore, the test-beam data confirm that the contribution to the energy resolution arising from photo-electron statistics is approximately 1%/sqrt(E). These findings validate the expected calorimetric performance of the GRAiNITA concept and provide important input for the design and optimization of future full-scale detectors.
@article{arxiv.2512.03811,
title = {Studying the GRAiNITA concept: first test beam results},
author = {Sergey Barsuk and Oleg Bezshyyko and Ianina Boiaryntseva and Andrey Boyarintsev and Dominique Breton and Herve Chanal and Alexander M. Dubovik and Larysa Golinka-Bezshyyko and Carlos Dominguez Goncalves and Yingrui Hou and Giulia Hull and Miktat Imre and Denys Klekots and Jacques Lefrancois and Jihane Maalmi and Magali Magne and Bernard Mathon and Stéphane Monteil and Sebastien Olmo and David Picard and Marie-Helene Schune and Irina Tupitsyna and Mykhailo Yeresko},
journal= {arXiv preprint arXiv:2512.03811},
year = {2026}
}