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"Offset Tile Calorimetry R&D"

We are proposing to develop a scintillator based electromagnetic/hadronic calorimeter with tiles offset in alternate layers. In this manner we develop a given granularity with an effective reduction of a factor of 4 in the number of readout channels. This reduces the costs substantially.

The goals is, first, to prove, via simulation, that the design has the resolution needed to separate two photon from single photon signals and, second, that we have the energy resolution to separate W and Z hadronic jets via the effective mass reconstruction. This simulation effort is being done with undergraduates. We want to show that this design is cheaper than others for any detector. Clearly this design is more effective the larger the radius of the detector; hence we are more appropriate for the LDC and GLD detector concepts but we will also test our design with the SiD detector concept.

We are presently the only institution working on this project.

We have significant results that were presented at Snowmass. One was the observation that there are a number of low energy tracks that loop in the calorimeter part of the detector. The removal of those hits near the end of the loop is important for a good energy flow algorithm. Our student, Jason Gray, has developed an algorithm that traces these using the tracker as the initial trace. He finds that if the track re-enters the tracking medium, he needs to use the tracking hits to find the last hits in the calorimeter. This work is continuing. We also found that if we bend a scintillating green fiber into a 2 cm. radius there is a time dependent deterioration in the light transmission of the fiber (about 6% loss/year). Both these studies are continuing.

At present we are working on developing the simulation and on learning how to operate the silicon photosensors. The software structure we are using is the one developed by SLAC. We have imported it to Colorado and using the Colorado computing farm. We serve as testors of the software and report bugs as we find them. We also generate our calorimeter geometry files and the software needed to unravel the energy hit distributions produced by GEANT. In the scale of the next year we would like to develop our simulation to the point that we can demonstrate the resolution of our design. We also would like to understand the capabilities of the silicon photo-detectors. The present silicon photo-detectors need to be developed further if they are to be useful. We would like to continue to test these further.

In the scale of 2-3 years we would like to develop the readout electronics and build a prototype to carry out beam tests.

The critical needs for us is the support of a research associate, part time support for an electronics engineer and the purchase of electronics. Our initial first year funding for ILCR&D provided funding for 50% of a research associate and some funding for an electronics engineer. . We lost both in the second year. This has caused a dislocation in our simulation effort and in our ability to study the silicon photo-detectors. All our simulation effort and our study of silicon photo-detectors is being done with undergraduates using University funds. We need a more senior person to help with the more complicated software issues and an electronics engineer to help with the electronics. We also requested funds to work with a faculty member in the mechanical engineering department to carry out a "finite element analysis" of the structural integrity of a calorimeter module to determine how best to hold up the various elements so that they remain flat. This funding request was not supported.

In addition to this effort we are collaborating with Wolfgang Lohmann on the design of the Beam-Cal Detector that will be used to catch the two-photon background. We are simulating the Beam-Cal efficiency for the 20 mrad crossing angle case.

Please address the following questions in your statement.

  • What are the goals of this R&D project. How does this R&D project address the needs of one or more of the detector concepts?

  • If there are multiple institutions participating in this project, please describe the distribution of responsibilities.

  • Are there significant recent results?

  • What are the plans for the near future(about 1 year)? What are the plans on a time scale of 2 to 3 years?

  • Are there critical items that must be addressed before significant results can be obtained from this project?

  • Is the support for this project sufficient? Are there significant improvements that could be made with additional support?