Pierre Auger Observatory Central Laser Facility Upgrade

该合同将资助升级位于皮埃尔·奥格天文台（PAO）中心附近的中央激光“测试光束”设施（CLF）。PAO利用大气作为一个巨大的量热计来测量已知存在的最高能量粒子。在这些极端能量下（1-100 EeV; 1 EeV = 10^18 eV； 1 eV是电子或质子被一伏特电压加速时获得的能量），传统上用于表征基于加速器的探测器的粒子测试束根本不存在。然而，从脉冲紫外线（UV）激光束散射到大气中的光将产生轨迹，这些轨迹可以被同样的荧光探测器记录下来，这些荧光探测器可以记录大量空气阵雨的轨迹。在一个5毫焦耳的紫外激光轨道和一个100 EeV的风淋之间存在近似的有效光学等效。拟议的CLF升级将增加一个拉曼激光雷达接收器和一个机器人光度校准系统，并进行相关改进。它将针对三个具体领域：1。使用“超级测试光束”对荧光检测器的端到端光度校准进行交叉检查，荧光检测器为天文台设置能量刻度。2. 在检测到特别感兴趣的空气阵雨的几分钟内，拉曼接收器将对气溶胶光学深度剖面和水蒸气剖面进行独立的精确测量。我们感兴趣的事件包括在混合模式下探测到的高能候选者，来自射电星系半人马座A附近区域的空气簇雨，以及具有可能不符合标准形状的簇雨轮廓的外来候选者。气溶胶光学深度是应用于风淋重建的最大时变校正量。3. 系统比较由拉曼激光雷达接收机测量的气溶胶光学深度剖面和目前用于填充天文台气溶胶剖面数据库的侧散射方法。这种比较对于混杂数据的伸长率分析尤其重要，表明颗粒组成可能在10 EeV以上转变为较重的原色。CSM的本科生自然会参与研究，因为他们需要完成一个高级设计项目作为他们课程的一部分。拉曼激光雷达是一种标准的气溶胶剖面测量技术，它将提高非传统方法收集的大气数据库的实用性。这将使我们能够与大气科学界的其他数据集进行更直接的比较。

This award will assist in funding an upgrade to the Central Laser "test beam" Facility (CLF) located near the center of the Pierre Auger Observatory (PAO). The PAO uses the atmosphere as a giant calorimeter to measure the highest energy particles known to exist. At these extreme energies (1-100 EeV; 1 EeV = 10^18 eV; 1 eV is the energy an electron or proton gains when it is accelerated by a voltage of one Volt), particle test beams, traditionally used to characterize accelerator based detectors, simply do not exist. However, light scattered out of a pulsed Ultra-Violet (UV) laser beam directed into the atmosphere will generate tracks that can be recorded by the same fluorescence detectors that record tracks from extensive air showers. There is an approximate effective optical equivalence between a 5 milliJoule UV laser track and a 100 EeV air shower. The proposed CLF upgrade will add a Raman LIDAR receiver and a robotic photometric calibration system, and make related improvements. It will target three specific areas:1. Use the "super test beam" to crosscheck the end-to-end photometric calibration of the fluorescence detector which sets the energy scale for the observatory. 2. Within a few minutes of the detection of air-showers of particular interest, the Raman receiver will make an independent precision measurement of the aerosol optical depth profile and water vapor profile. Events of interest include very high energy candidates detected in hybrid mode, air showers from the region near the radio galaxy Centaurus A, and exotic candidates with shower profiles that may not fit the standard shape. Aerosol optical depth is the largest time varying correction applied to air shower reconstruction. 3. Systematically compare the aerosol optical depth profiles measured by the Raman LIDAR receiver and by the side-scatter method currently used to fill the observatory's aerosol profile database. This comparison is especially important to the elongation rate analysis of hybrid data that suggests the particle composition may transition to heavier primaries above 10 EeV.CSM undergraduates are naturally involved in the research, as they are required to complete a senior design project as part of their curriculum. Raman LIDAR is a standard aerosol profile measurement technique that will enhance the usefulness of the atmospheric data base collected by non-traditional methods. This will enable more direct comparisons with other data sets in the atmospheric science community.