Purdue University Calumet joined the Compact Muon Solenoid (CMS) Collaboration in 2005. The high energy physics group is led by Prof. Neeti Parashar and consists of a post-doctoral fellow (Dr. Pratima Jindal), one physics undergraduate student (Tim Polka) and one computer science undergraduate student (Akhil Arora) working on this experiment.
Our main contribution has been to the Forward Pixel Detector of CMS, also often referred to as the Forward Pixel Disks. This is an integral component of the CMS Tracker. The design of the Forward Pixel detector is a complex one. It is comprised of 4 circular disks, two on each side of the Pixel Barrel. The inner and the outer diameter of each disk are 6 cm and 15 cm, respectively. The η coverage of these disks is from 1.5 to 2.25. Each of the four disks includes 24 wedge shaped blades arranged in a turbine like geometry. Each Blade is rotated 20 degrees around their radial symmetry axis to increase charge sharing among pixels. This would provide a hit resolution of ~ 15 μm.
Purdue University Calumet has delivered the geometry of the Forward Pixel Disks, which was developed anew. The older geometry was not user friendly, very difficult to modify and non-readable by the users. Therefore, we developed a new package, which uses the detector description database (DDD) interface for the XML (eXtensive Markup Language) to GEANT simulation. The DDD description of the Forward Pixel detector is based on the precise measurements of different components. Most of the geometry files are written in XML and the usage of symmetry is maximized.
We have also contributed very heavily to the construction of the disks themselves at the Silicon Detector Facility (Sidet). Our group has been responsible for burn-in tests for the plaquettes and panels used in the construction of the Forward Pixel detector. Purdue Calumet group has performed the second largest number of shifts from an institution amounting to a total of 11% of the total shifts and highest by an individual (post-doc) required to successfully build the disks.
The material budget study is an important step in the implementation of the detector. It also serves as a strong consistency check between hardware and software. We reviewed materials from the smallest units up to the whole structure.
Our current activities are
• Geometry Development for the Upgraded Forward Pixel Geometry
• Tracker Offline Shift Co-Coordinator at FNAL
• Perform b-tagging simulation studies at the LPC and CMS b-tagging groups
• Observation of top signal in semi-leptonic (electron) decay channel and measurement of electron efficiency using Tag and Probe Method at the LPC leptons + jets + met group
• QCD studies at CMS: Inclusive jet cross-section
• Establishing a Tier-3 Center for CMS
We are very excited to embark on the discovery prospects as the LHC injects the proton-proton collisions.