Quarknet Summer Research:

Research Summaries:



Summer 2006

*Fiber Cleaving

Three thousand fibers were cleaved and ordered this summer with proceedures developed in our lab. They are to be placed in a prototype detector called the ZDC (Zero-Degree Calorimeter). This detector will sit just off the beam at CERN where it will collect data that has never been looked at before.
[Image: Quarknet Fiber Research]

*Tyvek™ vs. Milar™ Reflectivity

There was a question as to the manufacturer’s claim that Milar™ was as reflective as Tyvek™. Since these materials are in heavy use in our detectors, it was our lab’s task to test the reflectivity of both. An experiment was set up to measure the reflectivity of both substances through the visible spectrum and into the UV. The fact that Milar™ was a diffuse reflector seemed to complicate matters a bit, but an experiment was run to justify or rebuke manufacturers claims.

*Plate Uniformity Scans:

Threading optical fibers through a scintillating plate has become an option to some physicists. The uniformity of these plates is a very important issue in using this method for detection. Scans were run of plates with differing patterns of fibers to judge the feasibility of using this method in a calorimeter. Here, Mr. Like is seen overlooking the XY scanner that was used in a dark box to move the plates during the scans.
[Image: Quarknet Teachers]

*Fiber Continuity After Intense Radiation

Our lab has done fiber radiation damage studies for a number of years. We have radiated our fibers everywhere from Cesium sources at the University of Iowa Hospitals, to the neutron beam at Argonne National Laboratories outside Chicago. This year fibers were cleaved and a baseline spectrum was taken. The fibers will be placed in the REM hole (just 10 inches) from the neutron source at Argonne. After they are radiated this fall, a spectrum will then be taken and compared to the baseline to test for damage.

Previous Years – 1999-2005

HF Design

Much of the radiation damage data was used by the faculty at the University of Iowa in their design of the forward calorimeter in CMS. This included the choice of optical fibers and PMTs used in the machine.
[Image: HCAL]

HF Materials Testing

Pete Bruecken, Ron Newland, Bill Cox, and Chris Like worked with high school students over a number of years testing materials to be used in HF. The most notable of these was the testing that led to the choice of PMT used in the detector. After building a light-tight lab, tests were run for a variety of calibrational procedures including gain, linearity, and recovery rate. After the choice of PMT was made, these same procedures were run on every PMT placed in HF.
[Image: Aaron Sartor and Peter Bruecken]

HF Calibration

Mr. Bruecken worked for many summers on radiation damage studies, focusing mainly on optical fiber stability in high radiation. Chris Like worked for a summer learning Linux, C++, and Root in an effort to help the group crunch data from calibration runs for HF being held at CERN. Mr. Like looked at actual data and produced an analysis of linearity for an HF wedge.
[Image: Flux Chart]


Dolan Murphy has literally become the lab’s resident expert in using the LabView software. After their last programmer was lost to graduation a year ago, Dolan was called upon to run most of the equipment. He has gone from programming simple formulas, to running Data Aquisition via a CAMAC rack and PMT interfaces. His summer was spent programming LabView to interact with the various equipment used in the lab’s experiments. He also put in a lot of time analyzing the data from plate scans and Milar™/Tyvek™ tests. Dolan graduated high school in 2006 and will be attending the University of Washington in Seattle, majoring n physics.
[Image: Quarknet Student Dolan Murphy]

Next Generation Detectors

The Quarknet group at Iowa has had the opportunity during the actual construction of HF to work toward providing input and data on material studies for the next generation of particle detectors. This includes advancing optical fiber research with respect to high radiation, and the possibility of using scintillating plates or gas as a substitute.
[Image: Fiber Bundles]