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High-resolution detection system for time-of-flight electron spectrometry (open access)

High-resolution detection system for time-of-flight electron spectrometry

One of the key components of a time-of-flight (TOF) spectrometer is the detection system. In addition to high timing resolution, accurate two-dimensional imaging substantially broadensthe areas of applications of TOF spectrometers; for example, add a new dimension to angle-resolved photoemission spectroscopy (ARPES). In this paper we report on the recent developments of a high spatial (<50 mm) and timing (<130 ps) resolution imaging system capable of selective detection of electrons, ions and/or photons. Relative to our previously reported results, we have substantially improved the counting rate capabilities of the system especially for cases where the energy range of interest represents a small fraction of the incoming flux at the detector plane. The new system ignores all the events outside of a tunable time window substantially decreasing the dead time required for the event processing. That allows high-resolution TOF measurements within a given energy or momentum range and also can be used for distinguishing (or disabling) detection of photons versus detection of charged particles. The counting rate within a given energy window can be as high as ~;;400KHz at 10percent dead time. The electron detection system reported in the paper was developed for the TOF ARPES experiments at the Advanced Light …
Date: August 12, 2007
Creator: Hussain, Zahid; Tremsin, A.S.; Lebedev, G.V.; Siegmund, O.H.W.; Vallerga, J.V.; McPhate, J.B. et al.
Object Type: Article
System: The UNT Digital Library
Measuring Type Ia Supernova Distances and Redshifts From TheirMulti-band Light Curves (open access)

Measuring Type Ia Supernova Distances and Redshifts From TheirMulti-band Light Curves

The distance and redshift of a type Ia supernova can bedetermined simultaneously through its multi-band light curves. This factmay beused for imaging surveys that discover and obtain photometry forlarge numbers of supernovae; so many that it would be difficult to obtaina spectroscopic redshift for each. Using available supernova-analysistools we find that there are several conditions in which a viabledistance--redshift can be determined. Uncertainties in the effectivedistance at z~;0.3 are dominated by redshift uncertainties coupled withthe steepness of the Hubble law. By z~;0.5 the Hubble law flattens outand distance-modulus uncertainties dominate. Observations that giveS/N=50 at peak brightness and a four-day observer cadence in each ofgriz-bands are necessary to match the intrinsic supernova magnitudedispersion out to z=1.0. Lower S/N can be tolerated with the addition ofredshift priors (e.g., from a host-galaxy photometric redshift),observationsin an additional redder band, or by focusing on supernovaredshifts that have particular leverage for this measurement. Morestringent S/N requirements are anticipated as improved systematicscontrol over intrinsic color, metallicity, and dust is attempted to bedrawn from light curves.
Date: August 12, 2007
Creator: Kim, Alex G. & Miquel, Ramon
Object Type: Article
System: The UNT Digital Library
Complete momentum and energy resolved TOF electron spectrometerfor time-resolved photoemission spectroscopy (open access)

Complete momentum and energy resolved TOF electron spectrometerfor time-resolved photoemission spectroscopy

Over the last decade, high-resolution Angle-Resolved Photoemission Spectroscopy (ARPES) has emerged as a tool of choice for studying the electronic structure of solids, in particular, strongly correlated complex materials such as cuprate superconductors. In this paper we present the design of a novel time-of-flight based electron analyzer with capability of 2D in momentum space (kx and ky) and all energies (calculated from time of flight) in the third dimension. This analyzer will utilize an improved version of a 2D delay linedetector capable of imaging with<35 mm (700x700 pixels) spatial resolution and better than 120 ps FWHM timing resolution. Electron optics concepts and optimization procedure are considered for achieving an energy resolution less than 1 meV and an angular resolution better than 0.11.
Date: August 12, 2007
Creator: Hussain, Zahid; Lebedev, G.; Tremsin, A.; Siegmund, O.; Chen, Y.; Shen, Z. X. et al.
Object Type: Article
System: The UNT Digital Library
[Letter from Al Daniels to All Stonewall Club Members] (open access)

[Letter from Al Daniels to All Stonewall Club Members]

Letter from Al Daniels to "All Stonewall Club Members" on August 12, 2007, discussing Texas Stonewall Democratic Caucus bylaws, and for the revisions of term limits on officers.
Date: August 12, 2007
Creator: unknown
Object Type: Letter
System: The UNT Digital Library
Polk County Enterprise (Livingston, Tex.), Vol. 125, No. 63, Ed. 1 Sunday, August 12, 2007 (open access)

Polk County Enterprise (Livingston, Tex.), Vol. 125, No. 63, Ed. 1 Sunday, August 12, 2007

Semi-weekly newspaper from Livingston, Texas that includes local, state and national news along with advertising.
Date: August 12, 2007
Creator: Reddell, Valerie
Object Type: Newspaper
System: The Portal to Texas History
The Baytown Sun (Baytown, Tex.), Vol. 86, No. 258, Ed. 1 Sunday, August 12, 2007 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 86, No. 258, Ed. 1 Sunday, August 12, 2007

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: August 12, 2007
Creator: Clements, Clifford E.
Object Type: Newspaper
System: The Portal to Texas History
The Panola Watchman (Carthage, Tex.), Vol. 135, No. 59, Ed. 1 Sunday, August 12, 2007 (open access)

The Panola Watchman (Carthage, Tex.), Vol. 135, No. 59, Ed. 1 Sunday, August 12, 2007

Semiweekly newspaper from Carthage, Texas that includes local, state, and national news along with advertising.
Date: August 12, 2007
Creator: unknown
Object Type: Newspaper
System: The Portal to Texas History
Ultrasonic Examination of Double-Shell Tank 241-AZ-101. Examination Completed July 2007. (open access)

Ultrasonic Examination of Double-Shell Tank 241-AZ-101. Examination Completed July 2007.

AREVA NC Inc. (AREVA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AZ-101. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations. The purpose of this examination was to provide information that could be used to evaluate the integrity of the wall of the primary tank. The requirements for the ultrasonic examination of Tank 241-AZ-101 were to detect, characterize (identify, size, and locate), and record measurements made of any wall thinning, pitting, or cracks that might be present in the wall of the primary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-Plan-27202 (Jensen 2005) and summarized on page 1 of this document, are to be reported to CH2M HILL and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M HILL, all data is to be recorded on electronic media and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations. The results of the examination of Tank 241-AZ-101 have …
Date: August 12, 2007
Creator: Pardini, Allan F. & Weier, Dennis R.
Object Type: Report
System: The UNT Digital Library
[Stonewall Democrats of Denton County] (open access)

[Stonewall Democrats of Denton County]

Handwritten notes regarding Stonewall Democrats of Denton County on August 12, 2007. An agenda from the Stonewall Democrats of Denton County on August 12, 2007, discussing old and new businesses and announcements. A flyer for the first meeting of Stonewall Democrats of Denton County with contact information. MapQuest directions from Dallas to Lewisville, and driving directions.
Date: August 12, 2007
Creator: unknown
Object Type: Text
System: The UNT Digital Library
The Altus Times (Altus, Okla.), Vol. 109, No. 62, Ed. 1 Sunday, August 12, 2007 (open access)

The Altus Times (Altus, Okla.), Vol. 109, No. 62, Ed. 1 Sunday, August 12, 2007

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: August 12, 2007
Creator: Bush, Michael
Object Type: Newspaper
System: The Gateway to Oklahoma History
Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 92, No. 235, Ed. 1 Sunday, August 12, 2007 (open access)

Sapulpa Daily Herald (Sapulpa, Okla.), Vol. 92, No. 235, Ed. 1 Sunday, August 12, 2007

Daily newspaper from Sapulpa, Oklahoma that includes local, state, and national news along with advertising.
Date: August 12, 2007
Creator: Mattox, Jami
Object Type: Newspaper
System: The Gateway to Oklahoma History
The Express-Star (Chickasha, Okla.), Ed. 1 Sunday, August 12, 2007 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Sunday, August 12, 2007

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: August 12, 2007
Creator: Bush, Kent
Object Type: Newspaper
System: The Gateway to Oklahoma History