CYGNO is an international collaboration with the aim of operating a ▪ optical time projection chamber (TPC) for directional Dark Matter (DM) searches and solar neutrino spectroscopy, to be deployed at the Laboratori Nazionali del Gran Sasso (LNGS). A ▪/▪ (60/40) mixture is used, along with a triple Gas Electron Multiplier (GEM) cascade to amplify the ionisation signal. The scintillation produced in the electron avalanches is read out using a scientific complementary metal–oxide–semiconductor (sCMOS) camera. This solution has proven to provide very high sensitivity to interactions in the few ▪ energy range. The inclusion of a hydrogen-based gas will offer an even lighter target, resulting in a more efficient energy transfer in a DM particle collision, and consequently, a lower detection threshold. Additionally, longer track lengths of light nuclear recoils are easier to detect with a clearer direction. However, the addition of such gas will contribute to quenching the scintillation, jeopardizing the TPC performance. In this work, we demonstrate the feasibility of adding 1% to 5% isobutane to the ▪/▪ (60/40) mixture by measuring the respective absolute scintillation yield output. The overall scintillation produced in the charge avalanches is not drastically suppressed by quenching due to the isobutane addition. The presence of Penning transfer from excited He atoms to isobutane molecules increases the number of electrons in the avalanches, partially compensating for the loss of scintillation due to quenching. For the highest applied GEM voltage, the total number of photons produced in the avalanche per ▪ deposited in the absorption region presents a decrease of only a factor of about three, from to ▪, as the isobutane content increases from 0 to 5%. The quantification of the visible component of the scintillation shows that isobutane quenches both visible and ultraviolet (UV) photons emitted by ▪/▪.

中文翻译：

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CYGNO 中 - 和 - 异丁烷中 GEM 电子雪崩的二次闪烁产率 — 使用光学 TPC 进行定向暗物质搜索


CYGNO 是一项国际合作项目，旨在运营光学时间投影室 (TPC)，用于定向暗物质 (DM) 搜索和太阳中微子光谱学，将部署在大萨索国家实验室 (LNGS)。使用▪/▪ (60/40) 混合物以及三重气体电子倍增器(GEM) 级联来放大电离信号。使用科学互补金属氧化物半导体 (sCMOS) 相机可以读取电子雪崩中产生的闪烁。事实证明，该解决方案可以对少数能量范围内的相互作用提供非常高的灵敏度。氢基气体的加入将提供更轻的目标，从而在 DM 粒子碰撞中实现更有效的能量转移，从而降低检测阈值。此外，光核反冲的轨迹长度较长，更容易检测，方向更清晰。然而，添加此类气体将有助于淬灭闪烁，从而危及 TPC 性能。在这项工作中，我们通过测量各自的绝对闪烁产率输出，证明了在▪/▪ (60/40) 混合物中添加1% 至5% 异丁烷的可行性。由于添加异丁烷，电荷雪崩中产生的整体闪烁并未因淬灭而受到显着抑制。从激发态 He 原子到异丁烷分子的潘宁转移的存在增加了雪崩中的电子数量，部分补偿了由于猝灭而造成的闪烁损失。对于最高施加的 GEM 电压，当异丁烷含量从 0% 增加到 5% 时，沉积在吸收区域中的每 ▪ 雪崩产生的光子总数仅减少约三倍，即从 ▪ 到 ▪。 闪烁的可见光成分的量化表明异丁烷淬灭▪/▪ 发射的可见光和紫外(UV) 光子。