One of our current projects is to look at the design of an NLC detector; we would like to find a design that maximizes our ability to make precision measurements of supersymmetry at a reasonable cost. At the moment, we are looking at two detector designs, simply called the ``Small'' and the ``Large'' detector. In fact, both detectors have a very similar design which resembles most modern high energy physics experiments.
Like most collider experiments, both detector designs have onion-like layers of detectors surrounding the electron-positron interaction point (IP). There will be a silicon microstrip vertex detector very close to the IP which will track charged particles and precisely determine their directions and the decay vertex. Surrounding this will be some sort of tracking system inside of a solenoidal magnetic field; the curvature of the charged tracks will determine their momentum. Outside of this will be an EM calorimeter which will measure the energies of electromagnetic particles (electrons and photons). Then there would be a hadronic calorimeter which measures the energies of hadrons (protons, neutrons, pions, kaons, etc.). And finally there would be a muon detector to detect the muons that manage to make it through all the rest of the detector.
The Small detector design has a 6 Tesla magnetic field. This causes very low-energy charged background particles coming from the beams to curl up to a very small radius. The vertex detector can be put closer to the beam pipe, and the calorimeters can also be smaller. A small EM calorimeter means that it can be made higher precision for the same cost.
The Large detector design only has a 3 Tesla magnetic field, which means that all the detector elements are correspondingly larger. The calorimetry will not be as precise but the momentum measurement will be better (due to the larger tracking volume).
One of our projects is to examine both detector designs and see if one is significantly better at making precision supersymmetry measurements better than the other. We are also interested in trying different technologies (e.g. silicon strips vs. time projection chamber for the tracking detector, different longitudinal and transverse segmentation for the calorimetry, etc.).