AFP: Fast Timing System R&D Plans

As discussed in the Technical Proposal, we have developed a proof-of-concept of the fast timing detector system capable of 10 to 20 ps resolution, depending on the number of channels employed. There is still quite a bit of R&D required, however, to get to a full system prototype that is capable of being installed in mid-2013. This R&D falls into two main categories: 1) fairly routine refinements of the system, involving the detector layout and electronics chain, which are clearly doable and just need to be completed; 2) long term stability issues involving microchannel plate PMT lifetime, assessing the radiation hardness of components, and developing a system with sufficient radiation tolerance to operate for a year or more without intervention. The location at 220 m from the ATLAS IP has expected radiation levels around 2 1011 neutron-equivalent per cm2 at the beam pipe (this corresponds to a luminosity of 100 fb−1), decreasing with distance. At the position of the detector, MCP-PMT, and the pre-amplifier, the levels are expected to be 1010 or less. This leads to an integrated dose on the order of ∼ 200 Grays for a luminosity of 100 fb−1. We expect to install the remainder of the timing electronics in the alcove at 240 m, where the expected dose is of the order of 0.1 to 1 Gray. We plan to analyze radiation monitoring data as the luminosity increases, to develop a more thorough understanding of the radiation environment of the detector, and then plan irradiation studies of the various components in summer of 2012. An overview of the goals of the remaining R&D and timescales involved for both of these development categories are discussed below in the context of the three main components of the fast timing system: the detector, the photo-sensor, and the electronics.