Daniel John Karmgard

Thermal design and tests for the CMS HCAL readout box

A method is necessary to cool the electronics contained in the readout boxes for the CMS HCAL. The electronics to pre-amplify and digitize signals from the optical detectors will generate a large amount of heat that must be removed from the CMS HCAL system. To accomplish this a thermal management system has been designed that uses metallic extrusions, liquid coolant, and thermal foam to transfer the heat from the electronics to the exterior cooling system. Because the electronics are difficult to access throughout the life of the experiment, the temperature must be kept low to extend life expectancy. In order to test the concepts before the final design is implemented a thermal test station was built. Several methods to are under study to determine the best method of making the thermal routing from source of the heat to the liquid for heat removal. The test bed for this evaluation and methods to monitor the electronics temperature in situ are discussed.

Detection of ionizing radiation in coherent plates of scintillating plastic optical fibers

Fully functional imaging scintillating-glass fiber detectors have been fabricated by our group and operated successfully over many years. In this paper we present our initial efforts to produce coherent fiber-optic tracking detectors based upon organic plastic scintillating fiber materials. The goal is to create devices of relatively large volume that can be used in informal education settings and that likewise permit the imaging of trajectories of ionizing particles in real time as they pass through the material. To improve the rate of particle detection, coherent plates of sizeable volume (25mm × 25mm × 100mm or more) are desirable.

A cosmic ray detector telescope for use in informal and formal education settings

We have developed an orientable cosmic ray telescope based on scintillating tile and waveshifting optical fiber technology for hands-on laboratory use and for interactive public displays. The device is sensitive to ionizing radiation and is composed of four individual scintillating tiles into which are embedded double-clad optical fibers doped with waveshifter dye. These fibers are coupled to photomultiplier tubes (PMT). The telescope is mounted on an adjustable (rotatable) structure to allow the measurement of the cosmic ray rate as a function of angle relative to the zenith. This motion is controlled by the user through a computer-controlled stepper motor. The readout system allows data to be collected and uploaded to the Web enhancing the interactive experience and for follow-up analysis.

Fast, long-wavelength scintillators and waveshifters

Studies are presented of new blue-green to red emitting scintillator and waveshifter materials for tracking and calorimetry applications for the detection of ionizing radiation. Materials include plastic scintillators, liquid scintillators, and plastic scintillating and waveshifting fibers. Program goals are to develop faster and more efficient detection media for a variety of experimental applications

Waveshifters and scintillators for the detection of ionizing radiation

New waveshifter and scintillator materials are under development for use in detecting charged particles in tracking applications and for detecting showering particles in calorimetric applications. Goals have been to identify and produce fast and efficient dye materials that fluoresce in the middle of the visible spectrum where polystyrene and polyvinyltoluene have good optical transparency, to replace existing materials currently in use in the field of particle physics. As a result of this study, several fluorescent dyes have been identified with fast and efficient emission, that fluorescence in the green (/spl lambda/ /spl sim/ 490-520 nm), and from these a number waveshifter and scintillator materials have been fabricated.

Front-end electro-optical interfaces for CMS HCAL

The CMS experiment is a complex instrument to study particle physics at the energy frontier. An important detector subsystem within CMS is the hadron calorimeter or HCAL, consisting of four subsystems that cover the kinematic region |/spl eta/|<5. This paper provides details of the electro-optical interfaces for the central barrel subsystem that operates in a region of high magnetic field and converts scintillation signals from megatile sampling layers to lower geometry for energy measurement.