HgCdTe 256x256 NWIR FPA

Researchers developed a HgCdTe 256x256 focal plane array (FPA) which operates in the 1 to 5 micron band. This is presently the largest demonstrated HgCdTe FPA. The detector material is HgCdTe on sapphire (PACE-1 technology) which has a low thermal expansion mismatch with silicon. The multiplexer is a CMOS FET-switch device processed through a commercial silicon foundry. The multiplexer input is direct injection and the charge capacity is about 2 times 10 to the 7th power electrons. The kTC limited read noise is 400 electrons. Researchers demonstrated high background imaging using the device. The broadband quantum efficiency is measured to be 59 percent. Dark currents less than 0.1 pA were measured at 77 K for detectors processed on PACE-1 material with 4.9 microns cutoff. The dark currents decrease as the temperature is lowered, and researchers are presently studying the T less than 77 K characteristics. The interconnect yield is greater than 95 percent. The devices are available for astronomical applications

Laboratory and telescope use of the NICMOS2 128 x 128 HgCdTe array

The second generation of Hubble Space Telescope (HST) instruments will include a near-infrared instrument. This choice has driven the development of near-infrared arrays to larger sizes and lower read noises. Rockwell International has delivered an array for use in the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument; this array has been dubbed NICMOS2. NICMOS2 is a 128x128 array of HgCdTe diodes In-bonded to a switched MOSFET readout. The readout was specifically designed for astronomical use with the HST requirement of low read noise a prime goal. These arrays use detector material which is similar to that used by Rockwell in previous arrays (e.g., HgCdTe produced on a sapphire substrate), but the NICMOS2 devices differ substantially from other 128x128 arrays produced by Rockwell in having a read noise of only 30 electrons when read out using appropriate correlated sampling. NICMOS2 has now been characterized in the laboratory, and it has been used on groundbased telescopes

Low noise HgCdTe 128 x 128 SWIR FPA for Hubble space telescope

Large area focal plane arrays of unprecedented performance were developed for use in Near Infrared Camera and Multi-Object Spectrometer (NICMOS), a proposed Hubble Space Telescope refurbishment instrument. These FPAs are 128x128-element, HgCdTe hybrid arrays with a cutoff wavelength of 2.5 microns. The multiplexer consists of a CMOS field effect transistor switch array with a typical mean readout noise of less than 30 electrons. The detectors typically have a mean dark current of less than 10 electrons/s at 77 K, with currents below 2 electrons measured at 60 K (both at 0.5 V reverse bias). The mean quantum efficiency is 40 to 60 percent at 77 K for 1.0 to 2.4 microns. Functional pixel yield is typically greater than 99 percent, and the power consumption is approximately 0.2 mW (during readout only)

Trends in the Job Market for Librarians: 1985-2000

This article discusses the major influence that the information age has had on librarianship. Computer-related technology has changed the way librarians do their jobs, their duties and has created a whole new realm of opportunities for librarians. Data from the Library Journal annual salary surveys and the ALA Placement Center are included in charts and figures to track job market trends from 1985-2000. Issues such as salary, job mobility and education are also discussed

The Effects of Speech Impairment on Quality of Life over Time in Patients with Amyotrophic Lateral Sclerosis

Limited research exists on how speech impairments affect quality of life (QOL) factors over time in patients with amyotrophic lateral sclerosis (ALS). A review of the literature, including the history, disease course, and prevalence of ALS, is presented. Physical and psychosocial functioning, especially the decline of bulbar functioning’s potential impact on QOL factors and communication style, are outlined. This study is a follow-up study on a study by Duff, who found a significant difference in QOL relative to level of bulbar functioning in a cross-sectional design. The current study used a longitudinal design to look at bulbar functioning, specifically levels of speech, and how that affects certain aspects of QOL over time. This study used archival data, collected from a multidisciplinary clinic at three time points, and evaluated the following measures: ALS Functional Rating Scale–Revised (ALSFRS–R) and the ALS–Specific Quality of Life Measurement–Revised (ALSSQOL–R). ALSSQOL–R domains of Negative Emotion, Interaction with People and the Environment, Intimacy, and Bulbar Function were analyzed by repeated measures tests, and correlated to speech impairment over time. Results indicated that as speech became significantly more impaired, no significant differences were observed on the Negative Emotion, Interaction with People and the Environment, and Intimacy subscales. However, as the ability to speak declines over time, participants’ Bulbar Functioning subscale scores decreased. These findings suggest that increased bulbar symptoms are perceived as more problematic over time point. However, results also indicated that at the third time point (most recent clinic visit) the relationship between actual speech impairment and perceived bulbar functioning weakens

Human Resource Management in Today\u27s Academic Library: Meeting Challenges and Creating Opportunities.

This book is highly recommended for those with an interest in human resource management in libraries. Although the book focuses on academic libraries, the insights provided could be useful to all types of libraries. The varying nature of the chapters in this book would be beneficial for those in administrative and human resource positions, for students learning about the profession, and for those working within the profession. A quote by Sheila Creth in chapter 10 provides the best summary of this book: “The greatest opportunity for success in any academic library lies with the staff. As one colleague observed, our most valuable resource goes home every night

A Current Mode Detector Array for Gamma-Ray Asymmetry Measurements

We have built a CsI(Tl) gamma-ray detector array for the NPDGamma experiment to search for a small parity-violating directional asymmetry in the angular distribution of 2.2 MeV gamma-rays from the capture of polarized cold neutrons by protons with a sensitivity of several ppb. The weak pion-nucleon coupling constant can be determined from this asymmetry. The small size of the asymmetry requires a high cold neutron flux, control of systematic errors at the ppb level, and the use of current mode gamma-ray detection with vacuum photo diodes and low-noise solid-state preamplifiers. The average detector photoelectron yield was determined to be 1300 photoelectrons per MeV. The RMS width seen in the measurement is therefore dominated by the fluctuations in the number of gamma rays absorbed in the detector (counting statistics) rather than the intrinsic detector noise. The detectors were tested for noise performance, sensitivity to magnetic fields, pedestal stability and cosmic background. False asymmetries due to gain changes and electronic pickup in the detector system were measured to be consistent with zero to an accuracy of $10^{-9}$ in a few hours. We report on the design, operating criteria, and the results of measurements performed to test the detector array.Comment: 33 pages, 20 figures, 2 table

The ART of People Management in Libraries: Tips for Managing Your Most Vital Resource

This human resource centered book consists of 8 chapters, an epilogue, bibliography and index. The book was co-written by James McKinlay, a professional consultant with thirty years‟ experience and Vicki Williamson, the current Dean of the University of Saskatchewan Library. This book was written with current leaders and those aspiring to be leaders in mind. The authors stated that this was not intended to be an academic work but instead was written in a conversational style with real world example

Problem Patrons: All Shapes and Sizes

Every type of library will inevitably have problem patrons, but this article focuses mainly on public and academic libraries. As the times have changed, so has the magnitude of the problem patrons. Problems of the past seem irrelevant compared to some of the problems we are currently facing. Discussed in this article are particular types of problem behavior, including, but not limited to anger, harassment of staff, and homelessness. The types of each category include examples to illustrate each concern, and possible remedies