Design and Prototyping of a Scintillator-based Tail-catcher/Muon Tracker

Muon ID and Reconstruction

Many key physics channels expected to appear at the Linear Collider have muons in their final states. Given the smallness of the expected cross sections, high efficiency in tracking and identification of the muons will be paramount. Since the precise measurement of the muon momentum will be done with the central tracker, a high granularity muon system which can efficiently match hits in it with those in the tracker and calorimeter will be needed.

Energy Leakage

Hermeticity and resolution constraints require that the calorimeters be placed inside the superconducting coil to avoid serious degradation of calorimeter performance. On the other hand cost considerations associated with the size of the coil imply that the total calorimetric system will be relatively thin (4.5-5.5 $\lambda$). Thus, additional calorimetric sampling may be required behind the coil to estimate and correct for hadronic leakage.

Shower Validation

Current hadronic shower models differ significantly from each other. This puts conclusions on detector performances drawn from PFAs on rather shaky ground. Thus one of the most important goals of the LC test beam program is the validation of hadronic simulation packages. A TCMT which can provide a reasonably detailed picture of the very tail-end of showers will be very helpful in this task.

The TCMT prototype will have a fine and a coarse section distinguished by the thickness of the steel absorber plates. The fine section sitting directly behind the hadron calorimeter and having the same longitudinal segmentation as the HCAL, will provide a detailed measurement of the tail end of the hadron showers which is crucial to the validation of hadronic shower models, since the biggest deviations between models occurs in the tails. The following coarse section will serve as a prototype muon system for any design of a Linear Collider Detector and will facilitate studies of muon tracking and identification within the particle flow reconstruction framework. Additionally, the TCMT will provide valuable insights into hadronic leakage and punch-through from thin calorimeters and the impact of the coil in correcting for this leakage.