MRI Consortium: Development of Upgraded Stellar Intensity Interferometry Instrumentation for the VERITAS Observatory

甚高能量（VHE）伽马射线是在宇宙中一些最极端的环境中发生的粒子加速中产生的。作为天体物理信使，它们的观测为研究这些高能事件的条件和过程提供了重要的窗口。 该奖项支持仪器开发，以升级位于亚利桑那州阿马多的VERITAS伽马射线观测站的镜子和相机系统。 自2007年开始运行以来，VERITAS成像空气切伦科夫望远镜直接暴露在亚利桑那州的元素中，随着时间的推移影响了12米镜系统的响应。 镜面重铺和先进的保护涂层的新发展使望远镜的反射率恢复到几乎原来的状态成为可能，大大提高了天文台对VHE伽马射线的灵敏度。用于增强准直和带通滤波的一套补充焦平面仪器也将使望远镜观测到的有效反射镜面积增加约两倍。这些升级将大大增强正在进行的VERITAS天体物理光学VHE伽马射线观测任务，包括实时多信使后续行动，以及最近实施的新型恒星强度干涉测量（SII）计划。该奖项为学生和博士后研究人员提供了独特的培训机会，以开发这些新技术，这些新技术将增强现有的VERITAS天文台，并对将这些技术扩展到下一代切伦科夫望远镜阵列（CTA）至关重要。镜面和焦平面升级将安装在亚利桑那州现有的四台VERITAS望远镜上。在与原始镜子制造商的合作中，现有的镜子涂层将被剥离，新的铝和铪涂层将被应用到镜子表面，并添加石英（SiO2）涂层，以保护免受亚利桑那州恶劣天气的影响。一个加速计划，以迅速重新涂覆尽可能多的镜子，计划将迅速使望远镜的反射率达到80- 85%，提供30-35%的平均增加的光，这将提高天文台的灵敏度软光谱源约2倍。预计这种涂层技术将被证明更耐用，持续时间更长（长达5年），减少VERITAS和未来仪器的长期维护。焦平面光学活动将允许开发径向梯度干涉滤光器技术和大幅度减少焦平面噪声。这些发展可能为提高大型成像大气切伦科夫天文台（如VERITAS和CTA）的灵敏度提供未来的转型能力，以用于未来的天体物理学研究。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Very-high energy (VHE) gamma-rays are produced in the particle accelerations that occur in some of the most extreme environments in the Universe. As astrophysical messengers, their observation provides an important window to study the conditions and processes underway in these energetic events. This award supports the instrument development for upgrades to the mirror and camera systems of the VERITAS gamma-ray observatory located at Amado, AZ. In operation since 2007, the VERITAS imaging air Cherenkov telescopes are directly exposed to the Arizona elements, impacting the response of the 12 meter mirror systems over time. New developments in mirror resurfacing and advanced protective coatings make it possible to restore the reflectivity of the telescopes to nearly their original state, significantly enhancing the observatory’s sensitivity to VHE gamma rays across the full range of accessible energies. A complementary suite of focal plane instrumentation for enhanced collimation and bandpass filtering will also improve the effective mirror area observed by the telescopes by approximately a factor of two. Combined, the upgrades will significantly augment the on-going VERITAS observing missions of VHE gamma-rays from astrophysical optics, including real-time multi-messenger follow-ups, and the recently implemented novel stellar intensity interferometry (SII) program. The award provides unique opportunities for training of student and postdoctoral researchers in developing these new technologies that will enhance the existing VERITAS observatory and are critical to extending the techniques to the next generation Cherenkov Telescope Array (CTA). The mirror and focal plane upgrades will be installed on the existing four VERITAS telescopes in operation in Arizona. In cooperation with the original mirror manufacturer, the existing mirror coatings will be stripped and a new aluminum and hafnium coating will be applied to the mirror surface, with a quartz (SiO2) overcoat added for protection from the harsh Arizona elements. An accelerated program to rapidly recoat as many mirrors as possible is planned that will quickly bring the telescopes' reflectivity to 80-85%, providing a 30-35% average increase in light that will improve the observatory’s sensitivity to soft spectrum sources by approximately a factor of 2. It is anticipated that this overcoat technology will prove to be more durable and last longer (up to 5 years), reducing long-term maintenance for VERITAS and future instruments. The focal plane optics activities will allow for the development of the radial-gradient interference filter technology and a substantial reduction in focal plane noise. These developments may provide future transformational capacity for improving the sensitivity of large Imaging Atmospheric Cherenkov observatories, such as VERITAS and CTA, for future astrophysics research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.