A Monolithic Time Stretcher for Precision Time Recording

Identifying light mesons which contain only up/down quarks (pions) from those containing a strange quark (kaons) over the typical meter length scales of a particle physics detector requires instrumentation capable of measuring flight times with a resolution on the order of 20ps. In the last few years a large number of inexpensive, multi-channel Time-to-Digital Converter (TDC) chips have become available. These devices typically have timing resolution performance in the hundreds of ps regime. A technique is presented that is a monolithic version of ``time stretcher'' solution adopted for the Belle Time-Of-Flight system to address this gap between resolution need and intrinsic multi-hit TDC performance.Comment: 9 pages, 15 figures, minor corrections made, to appear as JINST_008

Remarks on a Paper of Leighton

Counterexamples to theorems for zeros of solutions of second order linear differential equation

High Voltage CMOS Control Interface for Astronomy - Grade Charged Coupled Devices

The Pan-STARRS telescope consists of an array of smaller mirrors viewed by a Gigapixel arrays of CCDs. These focal planes employ Orthogonal Transfer CCDs (OTCCDs) to allow on-chip image stabilization. Each OTCCD has advanced logic features that are controlled externally. A CMOS Interface Device for High Voltage has been developed to provide the appropiate voltage signal levels from a readout and control system designated STARGRASP. OTCCD chip output levels range from -3.3V to 16.7V, with two different output drive strenghts required depending on load capacitance (50pF and 1000pF), with 24mA of drive and a rise time on the order of 100ns. Additional testing ADC structures have been included in this chip to evaluate future functional additions for a next version of the chip.Comment: 13 pages, 17 gigure

Anxiety and Stress Relief for Youth

The project that I chose to do for my capstone project was to create an interactive workbook for youth to help them understand anxiety and stress. I found that there was a need for youth to have a tool to learn to cope with anxiety and stress. The words anxiety and stress have both become buzzwords amongst middle school and high school students, but do they really understand what it is and how to deal with it? This workbook will give them an arsenal of tools and resources to assist them with learning more about these buzzwords and most importantly, learn how to deal with them. As a parent of 4 children, I have found that teenage years are the hardest for our youth and the most pressure is put on them. It is heartbreaking to watch our youth struggle with such an adult subject. Our society has put many pressures on these young adults, and it is necessary for us to help them learn how to face these pressures head on and with a brave face on

Pedagogy of Respect: The Inter-Generational Influence of Black Women

There is a large corpus of literature that not only speaks to the nature and qualities of Black women teachers, but that further disrupts the way these educators have been historically located at the margins of \u27education,\u27 by highlighting their political and culturally relevant/responsive approaches (Ladson- Billings, 1992/1994/2000; Gay, 2000; Beauboeuf-Lafontant, 1997/1999/2002; Irvine, 1989/1990/2003; Irvine & Hill, 1990; Collins, 2000; Siddle Walker, 1996/2005; Dixson, 2002/2005; Dingus, 2003, among others). This work, that looks at the larger political movement of Black women teachers, comes at a time when researchers are beginning to better blur the traditional boundaries that defined ‘center’ and ‘margin’ for educators. In this piece Fasching-Varner presents vignettes that describe the pedagogy of Black female teachers whom educated him, showing how they each have embodied various aspects of Respect as has been (re)defined by Lawrence-Lightfoot (2000/2001), and how that pedagogy informed his own work with students, particularly African American and Latino/a students

Deviations from ozone photostationary state during the International Consortium for Atmospheric Research on Transport and Transformation 2004 campaign: Use of measurements and photochemical modeling to assess potential causes

Nitric oxide (NO) and nitrogen dioxide (NO2) were monitored at the University of New Hampshire Atmospheric Observing Station at Thompson Farm (TF) during the ICARTT campaign of summer 2004. Simultaneous measurement of ozone (O3), temperature, and the photolysis rate of NO2 (jNO2) allow for assessment of the O3 photostationary state (Leighton ratio, Φ). Leighton ratios that are significantly greater than unity indicate that peroxy radicals (PO2), halogen monoxides, nitrate radicals, or some unidentified species convert NO to NO2 in excess of the reaction between NO and O3. Deviations from photostationary state occurred regularly at TF (1.0 ≤ Φ ≤ 5.9), particularly during times of low NOx (NOx = NO + NO2). Such deviations were not controlled by dynamics, as indicated by regressions between Φ and several meteorological parameters. Correlation with jNO2 was moderate, indicating that sunlight probably controls nonlinear processes that affect Φ values. Formation of PO2 likely is dominated by oxidation of biogenic hydrocarbons, particularly isoprene, the emission of which is driven by photosynthetically active radiation. Halogen atoms are believed to form via photolysis of halogenated methane compounds. Nitrate radicals are believed to be insignificant. Higher Φ values are associated with lower mixing ratios of isoprene and chloroiodomethane and lower ratios of NOx to total active nitrogen, indicating that photochemical aging may very well lead to increased Φ values. PO2 levels calculated using a zero‐dimensional model constrained by measurements from TF can account for 71% of the observed deviations on average. The remainder is assumed to be associated with halogen atoms, most likely iodine, with necessary mixing ratios up to 0.6 or 1.2 pptv, for chlorine and iodine, respectively

TARGET: A multi-channel digitizer chip for very-high-energy gamma-ray telescopes

The next-generation very-high-energy (VHE) gamma-ray observatory, the Cherenkov Telescope Array, will feature dozens of imaging atmospheric Cherenkov telescopes (IACTs), each with thousands of pixels of photo-sensors. To be affordable and reliable, reading out such a mega-channel array requires event recording technology that is highly integrated and modular, with a low cost per channel. We present the design and performance of a chip targeted to this application: the TeV Array Readout with GSa/s sampling and Event Trigger (TARGET). This application-specific integrated circuit (ASIC) has 16 parallel input channels, a 4096-sample buffer for each channel, adjustable input termination, self-trigger functionality, and tight window-selected readout. We report the performance of TARGET in terms of sampling frequency, power consumption, dynamic range, current-mode gain, analog bandwidth, and cross talk. The large number of channels per chip allows a low cost per channel (\10 to \20 including front-end and back-end electronics but not including photosensors) to be achieved with a TARGET-based IACT readout system. In addition to basic performance parameters of the TARGET chip itself, we present a camera module prototype as well as a second-generation chip (TARGET~2), both of which have been produced.Comment: 16 pages, 15 figures, version 3 (matches version published in Astroparticle Physics