Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC and its Radiological Considerations (open access)

Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC and its Radiological Considerations

Facility for Advanced Accelerator Experimental Tests (FACET) in SLAC will be used to study plasma wakefield acceleration. FLUKA Monte Carlo code was used to design a maze wall to separate FACET project and LCLS project to allow persons working in FACET side during LCLS operation. Also FLUKA Monte Carlo code was used to design the shielding for FACET dump to get optimum design for shielding both prompt and residual doses, as well as reducing environmental impact. FACET will be an experimental facility that provides short, intense pulses of electrons and positrons to excite plasma wakefields and study a variety of critical issues associated with plasma wakefield acceleration [1]. This paper describes the FACET beam parameters, the lay-out and its radiological issues.
Date: August 22, 2011
Creator: Mao, X.S.; Leitner, M.Santana & Vollaire, J.
Object Type: Article
System: The UNT Digital Library
LITERATURE REVIEW OF BORIC ACID SOLUBILITY DATA (open access)

LITERATURE REVIEW OF BORIC ACID SOLUBILITY DATA

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system replaces the current dilute nitric acid strip solution with 0.01 M boric acid. This literature study is performed to determine if there is a potential for boric acid to crystallize in the lines with emphasis on the transfer lines to the Defense Waste Processing Facility. This report focuses on the aqueous phase chemistry of boric acid under conditions relevant to MCU and SWPF. Operating and transfer conditions examined for the purpose of this review include temperatures between 13 C (McLeskey, 2008) and 45 C (Fondeur, 2007) and concentrations from 0 to 3M in nitric acid as well as exposure of small amounts of entrained boric acid in the organic phase to the sodium hydroxide caustic wash stream. Experiments were also conducted to observe any chemical reactions and off-gas generation that could occur when 0.01 M boric acid solution mixes with 3 M nitric acid solution and vice versa. Based on the low concentration (0.01M) of boric acid in the MCU/SWPF strip acid and the moderate operating temperatures (13 C to 45 C), …
Date: September 22, 2011
Creator: Crapse, K. & Kyser, E.
Object Type: Report
System: The UNT Digital Library
Demonstration of a Plasma Mirror Based on a Laminar Flow Water Film (open access)

Demonstration of a Plasma Mirror Based on a Laminar Flow Water Film

A plasma mirror based on a laminar water film with low flow speed 0.5-2 cm/s has been developed and characterized, for use as an ultrahigh intensity optical reflector. The use of flowing water as atarget surface automatically results in each laser pulse seeing a new interaction surface and avoids the need for mechanical scanning of the target surface. In addition, the breakdown of water does notproduce contaminating debris that can be deleterious to vacuum chamber conditions and optics, such as is the case when using conventional solid targets. The mirror exhibits 70percent reflectivity, whilemaintaining high-quality of the reflected spot.
Date: July 22, 2011
Creator: Panasenko, Dmitriy; Shu, Anthony J.; Gonsalves, Anthony; Nakamura, Kei; Matlis, Nicholas H.; Toth, Csaba et al.
Object Type: Article
System: The UNT Digital Library
DEVELOPMENT OF CRYSTALLINE CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES (open access)

DEVELOPMENT OF CRYSTALLINE CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES

The Savannah River National Laboratory (SRNL) is developing crystalline ceramic waste forms to incorporate CS/LN/TM high Mo waste streams consisting of perovskite, hollandite, pyrochlore, zirconolite, and powellite phase assemblages. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase crystalline ceramics. Fiscal Year 2011 (FY11) activities included (i) expanding the compositional range by varying waste loading and fabrication of compositions rich in TiO{sub 2}, (ii) exploring the processing parameters of ceramics produced by the melt and crystallize process, (iii) synthesis and characterization of select individual phases of powellite and hollandite that are the target hosts for radionuclides of Mo, Cs, and Rb, and (iv) evaluating the durability and radiation stability of single and multi-phase ceramic waste forms. Two fabrication methods, including melting and crystallizing, and pressing and sintering, were used with the intent of studying phase evolution under various sintering conditions. An analysis of the XRD and SEM/EDS results indicates that the targeted crystalline phases of the FY11 compositions consisting of pyrochlore, perovskite, hollandite, zirconolite, and powellite were formed by both press and sinter and melt and crystallize processing methods. An evaluation of crystalline phase formation versus melt processing conditions …
Date: September 22, 2011
Creator: Fox, K. & Brinkman, K.
Object Type: Report
System: The UNT Digital Library
Carrots and Sticks: A Comprehensive Business Model for the Successful Achievement of Energy Efficiency Resource Standards Environmental Energy Technologies DivisionMarch 2011 (open access)

Carrots and Sticks: A Comprehensive Business Model for the Successful Achievement of Energy Efficiency Resource Standards Environmental Energy Technologies DivisionMarch 2011

Energy efficiency resource standards (EERS) are a prominent strategy to potentially achieve rapid and aggressive energy savings goals in the U.S. As of December 2010, twenty-six U.S. states had some form of an EERS with savings goals applicable to energy efficiency (EE) programs paid for by utility customers. The European Union has initiated a similar type of savings goal, the Energy End-use Efficiency and Energy Services Directive, where it is being implemented in some countries through direct partnership with regulated electric utilities. U.S. utilities face significant financial disincentives under traditional regulation which affects the interest of shareholders and managers in aggressively pursuing cost-effective energy efficiency. Regulators are considering some combination of mandated goals ('sticks') and alternative utility business model components ('carrots' such as performance incentives) to align the utility's business and financial interests with state and federal energy efficiency public policy goals. European countries that have directed their utilities to administer EE programs have generally relied on non-binding mandates and targets; in the U.S., most state regulators have increasingly viewed 'carrots' as a necessary condition for successful achievement of energy efficiency goals and targets. In this paper, we analyze the financial impacts of an EERS on a large electric utility …
Date: March 22, 2011
Creator: Satchwell, Andrew; Cappers, Peter & Goldman, Charles
Object Type: Article
System: The UNT Digital Library
LSST Charge-Coupled Device Calibration (open access)

LSST Charge-Coupled Device Calibration

The prototype charge-coupled device created at the Stanford Linear Accelerator Center for the Large Synoptic Survey Telescope must be tested to check its functionality and performance. It was installed into the Calypso telescope in Arizona in November of 2008 for this purpose. Since then it has taken many images of various astronomical objects. By doing photometry on standard stars in these images, we can compare our magnitude results to the known magnitudes of these stars. This comparison allows us to then determine the chip's performance and functional capabilities. Expecting to see first light in 2016, the Large Synoptic Survey Telescope (LSST) is an extremely large ground based telescope that anticipates funding and will be built in Chile. Described as 'Wide-Fast-Deep', the LSST will have an unprecedented wide field of view (ten square degrees for surveys), short exposures (fifteen to thirty seconds and still see faint objects), and the largest digital camera in the world. One of the goals hoped to be achieved with this camera is the measurement of dark matter using strong and weak gravitational lensing. Gravitational lensing occurs when a large cluster of galaxies distorts the light from a galaxy behind this cluster. This causes an arc of …
Date: June 22, 2011
Creator: Stout, Tiarra Johannas & /SLAC, /Idaho State U.
Object Type: Report
System: The UNT Digital Library
Analysis of Femtosecond Timing Noise and Stability in Microwave Components (open access)

Analysis of Femtosecond Timing Noise and Stability in Microwave Components

To probe chemical dynamics, X-ray pump-probe experiments trigger a change in a sample with an optical laser pulse, followed by an X-ray probe. At the Linac Coherent Light Source, LCLS, timing differences between the optical pulse and x-ray probe have been observed with an accuracy as low as 50 femtoseconds. This sets a lower bound on the number of frames one can arrange over a time scale to recreate a 'movie' of the chemical reaction. The timing system is based on phase measurements from signals corresponding to the two laser pulses; these measurements are done by using a double-balanced mixer for detection. To increase the accuracy of the system, this paper studies parameters affecting phase detection systems based on mixers, such as signal input power, noise levels, temperature drift, and the effect these parameters have on components such as the mixers, splitters, amplifiers, and phase shifters. Noise data taken with a spectrum analyzer show that splitters based on ferrite cores perform with less noise than strip-line splitters. The data also shows that noise in specific mixers does not correspond with the changes in sensitivity per input power level. Temperature drift is seen to exist on a scale between 1 and …
Date: June 22, 2011
Creator: Whalen, Michael R. & /SLAC, /Stevens Tech.
Object Type: Report
System: The UNT Digital Library
Laser Wakefield Acceleration Beyond 1 Gev Using Ionization Induced Injection* (open access)

Laser Wakefield Acceleration Beyond 1 Gev Using Ionization Induced Injection*

A series of laser wake field accelerator experiments leading to electron energy exceeding 1 GeV are described. Theoretical concepts and experimental methods developed while conducting experiments using the 10 TW Ti:Sapphire laser at UCLA were implemented and transferred successfully to the 100 TW Callisto Laser System at the Jupiter Laser Facility at LLNL. To reach electron energies greater than 1 GeV with current laser systems, it is necessary to inject and trap electrons into the wake and to guide the laser for more than 1 cm of plasma. Using the 10 TW laser, the physics of self-guiding and the limitations in regards to pump depletion over cm-scale plasmas were demonstrated. Furthermore, a novel injection mechanism was explored which allows injection by ionization at conditions necessary for generating electron energies greater than a GeV. The 10 TW results were followed by self-guiding at the 100 TW scale over cm plasma lengths. The energy of the self-injected electrons, at 3 x 10{sup 18} cm{sup -3} plasma density, was limited by dephasing to 720 MeV. Implementation of ionization injection allowed extending the acceleration well beyond a centimeter and 1.4 GeV electrons were measured.
Date: March 22, 2011
Creator: Marsh, K. A.; Clayton, C. E.; Joshi, C.; Lu, W.; Mori, W. B.; Pak, A. et al.
Object Type: Article
System: The UNT Digital Library
SLUDGE BATCH 7 ACCEPTANCE EVALUATION: RADIONUCLIDE CONCENTRATIONS IN TANK 51 SB7 QUALIFICATION SAMPLE PREPARED AT SRNL (open access)

SLUDGE BATCH 7 ACCEPTANCE EVALUATION: RADIONUCLIDE CONCENTRATIONS IN TANK 51 SB7 QUALIFICATION SAMPLE PREPARED AT SRNL

Presented in this report are radionuclide concentrations required as part of the program of qualifying Sludge Batch Seven (SB7) for processing in the Defense Waste Processing Facility (DWPF). The SB7 material is currently in Tank 51 being washed and prepared for transfer to Tank 40. The acceptance evaluation needs to be completed prior to the transfer of the material in Tank 51 to Tank 40. The sludge slurry in Tank 40 has already been qualified for DWPF and is currently being processed as SB6. The radionuclide concentrations were measured or estimated in the Tank 51 SB7 Qualification Sample prepared at Savannah River National Laboratory (SRNL). This sample was prepared from the three liter qualification sample of Tank 51 sludge slurry (HTF-51-10-125) received on September 18, 2010. The sample was delivered to SRNL where it was initially characterized in the Shielded Cells. With consultation from the Liquid Waste Organization, the qualification sample was then modified by several washes and decants, which included addition of Pu from H Canyon and sodium nitrite per the Tank Farm corrosion control program. This final slurry now has a composition expected to be similar to that of the slurry in Tank 51 after final preparations have …
Date: February 22, 2011
Creator: Pareizs, J. & Hay, M.
Object Type: Report
System: The UNT Digital Library
Sources of the Radio Background Considered (open access)

Sources of the Radio Background Considered

We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed …
Date: August 22, 2011
Creator: Singal, J.; Stawarz, L.; Lawrence, A. & Petrosian, V.
Object Type: Article
System: The UNT Digital Library
Aerosol Imaging with a Soft X-ray Free Electron Laser (open access)

Aerosol Imaging with a Soft X-ray Free Electron Laser

Lasers have long played a critical role in the advancement of aerosol science. A new regime of ultrafast laser technology has recently be realized, the world's first soft xray free electron laser. The Free electron LASer in Hamburg, FLASH, user facility produces a steady source of 10 femtosecond pulses of 7-32 nm x-rays with 10{sub 12} photons per pulse. The high brightness, short wavelength, and high repetition rate (>500 pulses per second) of this laser offers unique capabilities for aerosol characterization. Here we use FLASH to perform the highest resolution imaging of single PM2.5 aerosol particles in flight to date. We resolve to 35 nm the morphology of fibrous and aggregated spherical carbonaceous nanoparticles that existed for less than two milliseconds in vacuum. Our result opens the possibility for high spatialand time-resolved single particle aerosol dynamics studies, filling a critical technological need in aerosol science.
Date: August 22, 2011
Creator: Bogan, Michael J.; /SLAC /LLNL, Livermore; Boutet, Sebastien; /SLAC National Accelerator Laboratory; Chapman, Henry N.; U., /DESY /Hamburg et al.
Object Type: Article
System: The UNT Digital Library
PERMEABILITY TESTING OF SIMULATED SALTSTONE CORE AND VAULT 4 CELL E SALTSTONE (open access)

PERMEABILITY TESTING OF SIMULATED SALTSTONE CORE AND VAULT 4 CELL E SALTSTONE

The Engineering Process Development Group (EPD) of the Savannah River National Laboratory (SRNL) prepared simulated saltstone core samples to evaluate the effect of sample collection by coring on the permeability of saltstone. The Environmental Restoration Technology Section (ERTS) of the SRNL was given the task of measuring the permeability of cores of simulated saltstone. Saltstone samples collected from Vault 4 Cell E using both dry and wet coring methods were also submitted for permeability analysis. The cores from Vault 4 Cell E were in multiple pieces when they were recovered (Smith, 2008 Cheng et.al, 2009). Permeability testing was only performed on the portions of the core sample that were intact, had no visible fractures or cracks, and met the specifications for 'undisturbed specimens' identified in Method ASTM D5084-03 Standard Test Methods for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a Flexible Wall Permeameter that was used for the testing. Permeability values for cores of simulated saltstone compared with values from permeability tests conducted on molded saltstone samples by an independent laboratory using the same method. All hydraulic conductivity results for Vault 4 samples exceeded results for both molded and cored saltstone simulant samples. The average hydraulic conductivity result …
Date: August 22, 2011
Creator: Nichols, R. & Dixon, K.
Object Type: Report
System: The UNT Digital Library
Tape-Drive Based Plasma Mirror (open access)

Tape-Drive Based Plasma Mirror

We present experimental results on a tape-drive based plasma mirror which could be used for a compact coupling of a laser beam into a staged laser driven electron accelerator. This novel kind of plasma mirror is suitable for high repetition rates and for high number of laser shots. In order to design a compact, staged laser plasma based accelerator or collider [1], the coupling of the laser beam into the different stages represents one of the key issues. To limit the spatial foot print and thus to realize a high overall acceleration gradient, a concept has to be found which realizes this in-coupling within a few centimeters (cf. Fig 1). The fluence of the laser pulse several centimeters away from the acceleration stage (focus) exceeds the damage threshold of any available mirror coating. Therefore, in reference [2] a plasma mirror was suggested for this purpose. We present experiments on a tape-drive based plasma mirror which could be used to reflect the focused laser beam into the acceleration stage. Plasma mirrors composed of antireflection coated glass substrates are usually used to improve the temporal laser contrast of laser pulses by several orders of magnitudes [3,4]. This is particularly important for laser …
Date: July 22, 2011
Creator: Sokollik, Thomas; Shiraishi, Satomi; Osterhoff, Jens; Evans, Eugene; Gonsalves, Anthony; Nakamura, Kei et al.
Object Type: Article
System: The UNT Digital Library
The SuperB Accelerator: Overview and Lattice Studies (open access)

The SuperB Accelerator: Overview and Lattice Studies

SuperB aims at the construction of a very high luminosity (10{sup 36} cm{sup -2} s{sup -1}) asymmetric e{sup +}e{sup -} Flavour Factory, with possible location at the campus of the University of Rome Tor Vergata, near the INFN Frascati National Laboratory. In this paper the basic principles of the design and details on the lattice are given. SuperB is a new machine that can exploit novel very promising design approaches: (1) large Piwinski angle scheme will allow for peak luminosity of the order of 10{sup 36} cm{sup -2} s{sup -1}, well beyond the current state-of-the-art, without a significant increase in beam currents or shorter bunch lengths; (2) 'crab waist' sextupoles will be used for suppression of dangerous resonances; (3) the low beam currents design presents reduced detector and background problems, and affordable operating costs; (4) a polarized electron beam can produce polarized {tau} leptons, opening an entirely new realm of exploration in lepton flavor physics. SuperB studies are already proving useful to the accelerator and particle physics communities. The principle of operation is being tested at DAFNE. The baseline lattice, based on the reuse of all PEP-II hardware, fits in the Tor Vergata University campus site, near Frascati. A CDR …
Date: November 22, 2011
Creator: Biagini, M.E.; Boni, R.; Boscolo, M.; Drago, A.; Guiducci, S.; Preger, M. et al.
Object Type: Article
System: The UNT Digital Library
Comparison of 2006 IECC and 2009 IECC Commercial Energy Code Requirements for Kansas City, MO (open access)

Comparison of 2006 IECC and 2009 IECC Commercial Energy Code Requirements for Kansas City, MO

This report summarizes code requirements and energy savings of commercial buildings in climate zone 4 built to the 2009 IECC when compared to the 2006 IECC. In general, the 2009 IECC has higher insulation requirements for exterior walls, roof, and windows and have higher efficiency requirements for HVAC equipment (HVAC equipment efficiency requirements are governed by National Appliance Conversion Act of 1987 (NAECA), and are applicable irrespective of the IECC version adopted). The energy analysis results show that residential and nonresidential commercial buildings meeting the 2009 IECC requirements save between 6.1% and 9.0% site energy, and between 6.4% and 7.7% energy cost when compared to 2006 IECC. Analysis also shows that semiheated buildings have energy and cost savings of 3.9% and 5.6%.
Date: March 22, 2011
Creator: Huang, Yunzhi & Gowri, Krishnan
Object Type: Report
System: The UNT Digital Library
Data Acquisition in a High Harmonic Generation Lab and at LCLS (open access)

Data Acquisition in a High Harmonic Generation Lab and at LCLS

In this paper, we examine data acquisition in a high harmonic generation (HHG) lab and preliminary data analysis with the Cyclohexadiene Collaboration at the Linac Coherent Lightsource (LCLS) at SLAC National Accelerator Laboratory. HHG experiments have a large number of parameters that need to be monitored constantly. In particular, the pressure of the target is critical to HHG yield. However, this pressure can fluctuate wildly and without a tool to monitor it, it is difficult to analyze the correlation between HHG yield and the pressure. I used the Arduino microcontroller board and created a complementary MATLAB graphical user interface (GUI), thereby enhancing the ease with which users can acquire time-stamped parameter data. Using the Arduino, it is much easier to match the pressure to the corresponding HHG yield. Collecting data by using the Arduino and the GUI is flexible, user-friendly, and cost-effective. In the future, we hope to be able to control and monitor parts of the lab with the Arduino alone. While more parameter information is needed in the HHG lab, we needed to reduce the amount of data during the cyclohexadiene collaboration. This was achieved by sorting the data into bins and filtering out unnecessary details. This method …
Date: June 22, 2011
Creator: Hirokawa, Takako
Object Type: Report
System: The UNT Digital Library
Precise Measurement of the K - to Pi -E E- Decay (open access)

Precise Measurement of the K - to Pi -E E- Decay

A sample of 7253 K{sup {+-}} {yields} {pi}{sup {+-}}e{sup +}e{sup -}({gamma}) decay candidates with 1.0% background contamination has been collected by the NA 48/2 experiment at the CERN SPS, which allowed a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be BR = (3.11 {+-} 0.12) x 10{sup -7}, where the uncertainty includes also the model dependence. The shape of the form factor W(z), where z = (M{sub ee}/M{sub K}){sup 2}, was parameterized according to several models, and, in particular, the slope {delta} of the linear form factor W(z) = W{sub 0}(1 + {delta}z) was determined to be {delta} = 2.32 {+-} 0.18. A possible CP violating asymmetry of K{sup +} and K{sup -} decay widths was investigated, and a conservative upper limit of 2.1 x 10{sup -2} at 90% CL was established.
Date: November 22, 2011
Creator: Batley, J. R.; Culling, A. J.; Kalmus, G.; Lazzeroni, C.; Munday, D. J.; Slater, M. W. et al.
Object Type: Article
System: The UNT Digital Library
OXALATE MASS BALANCE DURING CHEMICAL CLEANING IN TANK 6F (open access)

OXALATE MASS BALANCE DURING CHEMICAL CLEANING IN TANK 6F

The Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRR personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 6F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate. Some conclusions from this work are: (1) Approximately 65% of the oxalate added as oxalic acid was removed with the decanted liquid. (2) Approximately 1% of the oxalate (added to the tank as oxalic acid) formed precipitates …
Date: July 22, 2011
Creator: Poirier, M. & Fink, S.
Object Type: Report
System: The UNT Digital Library
Observation Targeting for the Tehachapi Pass and Mid-Columbia Basin: WindSENSE Phase III Project Summary Report (open access)

Observation Targeting for the Tehachapi Pass and Mid-Columbia Basin: WindSENSE Phase III Project Summary Report

The overall goal of this multi-phased research project known as WindSENSE is to develop an observation system deployment strategy that would improve wind power generation forecasts. The objective of the deployment strategy is to produce the maximum benefit for 1- to 6-hour ahead forecasts of wind speed at hub-height ({approx}80 m). In Phase III of the project, the focus was on the Mid-Columbia Basin region which encompasses the Bonneville Power Administration (BPA) wind generation area shown in Figure 1 that includes Klondike, Stateline, and Hopkins Ridge wind plants. The typical hub height of a wind turbine is approximately 80-m above ground level (AGL). So it would seem that building meteorological towers in the region upwind of a wind generation facility would provide data necessary to improve the short-term forecasts for the 80-m AGL wind speed. However, this additional meteorological information typically does not significantly improve the accuracy of the 0- to 6-hour ahead wind power forecasts because processes controlling wind variability change from day-to-day and, at times, from hour-to-hour. It is also important to note that some processes causing significant changes in wind power production function principally in the vertical direction. These processes will not be detected by meteorological towers …
Date: October 22, 2011
Creator: Hanley, D
Object Type: Report
System: The UNT Digital Library
Impedances of Laminated Vacuum Chambers (open access)

Impedances of Laminated Vacuum Chambers

First publications on impedance of laminated vacuum chambers are related to early 70s: those are of S. C. Snowdon [1] and of A. G. Ruggiero [2]; fifteen years later, a revision paper of R. Gluckstern appeared [3]. All the publications were presented as Fermilab preprints, and there is no surprise in that: the Fermilab Booster has its laminated magnets open to the beam. Being in a reasonable mutual agreement, these publications were all devoted to the longitudinal impedance of round vacuum chambers. The transverse impedance and the flat geometry case were addressed in more recent paper of K. Y. Ng [4]. The latest calculations of A. Macridin et al. [5] revealed some disagreement with Ref. [4]; this fact stimulated us to get our own results on that matter. Longitudinal and transverse impendances are derived for round and flat laminated vacuum chambers. Results of this paper agree with Ref. [5].
Date: June 22, 2011
Creator: Burov, A. & Lebedev, V.
Object Type: Report
System: The UNT Digital Library
Improving Phase Measurement Procedures for Pump-Probe Experiments (open access)

Improving Phase Measurement Procedures for Pump-Probe Experiments

Pump-probe experiments use a visible laser to excite an atom or molecule, while an X-ray pulse measures its shape. The phases and pulse times of each beam are used to calculate the object's positing at a given time - a moving picture of the chemical reaction. Currently, the fastest X-ray pulses can travel a time-length of five femtoseconds. However, present-day phase measurements can only be done as quickly as 50 femtoseconds. The purpose of this research is to explore ways in which phase-timing measurements can be improved. Three experiments are undergone to find the key factors in phase-timing. Different frequency mixers, the radio frequency (RF) components used for phase measurement, are tested for the highest sensitivity. These same mixers are then tested using two different power splitters for the lowest noise-to-sensitivity ratio. Lastly, the temperature dependency of phase is explored by testing each component at a range of temperatures to see how the phase is affected. This research demonstrated that certain mixers were more sensitive than others; on average, one mixer performed the best with a sensitivity of 0.0230 V/ps. The results also showed that same mixer combined with one splitter gave the best noise-to-sensitivity ratio overall with an average …
Date: June 22, 2011
Creator: Perkins, Cara P.
Object Type: Report
System: The UNT Digital Library
Investigation into Nanostructured Lanthanum Halides and CeBr{sub 3} for Nuclear Radiation Detection (open access)

Investigation into Nanostructured Lanthanum Halides and CeBr{sub 3} for Nuclear Radiation Detection

This slide-show presents work on radiation detection with nanostructured lanthanum halides and CeBr{sub 3}. The goal is to extend the gamma energy response on both low and high-energy regimes by demonstrating the ability to detect low-energy x-rays and relatively high-energy activation prompt gamma rays simultaneously using the nano-structured lanthanum bromide, lanthanum fluoride, cerium bromide, or other nanocrystal material. Homogeneous and nano structure cases are compared.
Date: June 22, 2011
Creator: Guss, P., Guise, R., Mukhopadhyay, S., Yuan, D.
Object Type: Article
System: The UNT Digital Library
Calibration Analyses and Efficiency Studies for the Anti Coincidence Detector on the Fermi Gamma Ray Space Telescope (open access)

Calibration Analyses and Efficiency Studies for the Anti Coincidence Detector on the Fermi Gamma Ray Space Telescope

The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope provides charged particle rejection for the Large Area Telescope (LAT). We use two calibrations used by the ACD to conduct three studies on the performance of the ACD. We examine the trending of the calibrations to search for damage and find a timescale over which the calibrations can be considered reliable. We also calculated the number of photoelectrons counted by a PMT on the ACD from a normal proton. Third, we calculated the veto efficiencies of the ACD for two different veto settings. The trends of the calibrations exhibited no signs of damage, and indicated timescales of reliability for the calibrations of one to two years. The number of photoelectrons calculated ranged from 5 to 25. Large errors in the effect of the energy spectrum of the charged particles caused these values to have very large errors of around 60 percent. Finally, the veto efficiencies were found to be very high at both veto values, both for charged particles and for the lower energy backsplash spectrum. The Anti Coincidence Detector (ACD) on the Fermi Gamma Ray Space Telescope is a detector system built around the silicon strip tracker …
Date: June 22, 2011
Creator: Kachulis, Chris
Object Type: Report
System: The UNT Digital Library
Laboratory Directed Research and Development FY2010 Annual Report (open access)

Laboratory Directed Research and Development FY2010 Annual Report

A premier applied-science laboratory, Lawrence Livermore National Laboratory (LLNL) has at its core a primary national security mission - to ensure the safety, security, and reliability of the nation's nuclear weapons stockpile without nuclear testing, and to prevent and counter the spread and use of weapons of mass destruction: nuclear, chemical, and biological. The Laboratory uses the scientific and engineering expertise and facilities developed for its primary mission to pursue advanced technologies to meet other important national security needs - homeland defense, military operations, and missile defense, for example - that evolve in response to emerging threats. For broader national needs, LLNL executes programs in energy security, climate change and long-term energy needs, environmental assessment and management, bioscience and technology to improve human health, and for breakthroughs in fundamental science and technology. With this multidisciplinary expertise, the Laboratory serves as a science and technology resource to the U.S. government and as a partner with industry and academia. This annual report discusses the following topics: (1) Advanced Sensors and Instrumentation; (2) Biological Sciences; (3) Chemistry; (4) Earth and Space Sciences; (5) Energy Supply and Use; (6) Engineering and Manufacturing Processes; (7) Materials Science and Technology; Mathematics and Computing Science; (8) Nuclear …
Date: March 22, 2011
Creator: Jackson, K J
Object Type: Report
System: The UNT Digital Library