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Possibilities for Nuclear Photo-Science with Intense Lasers (open access)

Possibilities for Nuclear Photo-Science with Intense Lasers

The interaction of intense laser light with relativistic electrons can produce unique sources of high-energy x rays and gamma rays via Thomson scattering. ''Thomson-Radiated Extreme X-ray'' (T-REX) sources with peak photon brightness (photons per unit time per unit bandwidth per unit solid angle per unit area) that exceed that available from world's largest synchrotrons by more than 15 orders of magnitude are possible from optimally designed systems. Such sources offer the potential for development of ''nuclear photo-science'' applications in which the primary photon-atom interaction is with the nucleons and not the valence electrons. Applications include isotope-specific detection and imaging of materials, inverse density radiography, transmutation of nuclear waste and fundamental studies of nuclear structure. Because Thomson scattering cross sections are small, < 1 barn, the output from a T-REX source is optimized when the laser spot size and the electron spot size are minimized and when the electron and laser pulse durations are similar and short compared to the transit time through the focal region. The principle limitation to increased x-ray or gamma-ray brightness is ability to focus the electron beam. The effects of space charge on electron beam focus decrease approximately linearly with electron beam energy. For this reason, …
Date: June 26, 2006
Creator: Barty, C. J.; Hartemann, F. V.; McNabb, D. P.; Messerly, M.; Siders, C.; Anderson, S. et al.
Object Type: Article
System: The UNT Digital Library
Relative Contributions of Fossil and Contemporary Carbon sources to PM 2.5 Aerosols at Nine IMPROVE Network Sites (open access)

Relative Contributions of Fossil and Contemporary Carbon sources to PM 2.5 Aerosols at Nine IMPROVE Network Sites

Particulate matter aerosols contribute to haze diminishing vistas and scenery at National Parks and Wilderness Areas within the United States. To increase understanding of the sources of carbonaceous aerosols at these settings, the total carbon loading and {sup 14}C/C ratio of PM 2.5 aerosols at nine IMPROVE (Interagency Monitoring for Protection Of Visual Environments) network sites were measured. Aerosols were collected weekly in the summer and winter at one rural site, two urban sites, five sites located in National Parks and one site located in a Wildlife Preserve. The carbon measurements together with the absence of {sup 14}C in fossil carbon materials and the known {sup 14}C/C levels in contemporary carbon materials were used to derive contemporary and fossil carbon contents of the particulate matter. Contemporary and fossil carbon aerosol loadings varied across the sites and suggest different percentages of carbon source inputs. The urban sites had the highest fossil carbon loadings that comprised around 50% of the total carbon aerosol loading. The Wildlife Preserve and National Park sites together with the rural site had much lower fossil carbon loading components. At these sites, variations in the total carbon aerosol loading were dominated by non-fossil carbon sources. This suggests that …
Date: June 26, 2006
Creator: Bench, G; Fallon, S; Schichtel, B; Malm, W & McDade, C
Object Type: Article
System: The UNT Digital Library
The Express-Star (Chickasha, Okla.), Ed. 1 Monday, June 26, 2006 (open access)

The Express-Star (Chickasha, Okla.), Ed. 1 Monday, June 26, 2006

Daily newspaper from Chickasha, Oklahoma that includes local, state, and national news along with advertising.
Date: June 26, 2006
Creator: Bush, Kent
Object Type: Newspaper
System: The Gateway to Oklahoma History
Altus Times (Altus, Okla.), Vol. 108, No. 74, Ed. 1 Monday, June 26, 2006 (open access)

Altus Times (Altus, Okla.), Vol. 108, No. 74, Ed. 1 Monday, June 26, 2006

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: June 26, 2006
Creator: Bush, Michael
Object Type: Newspaper
System: The Gateway to Oklahoma History
Fast Compensation of Global Linear Coupling in Rhic Using Ac Dipoles. (open access)

Fast Compensation of Global Linear Coupling in Rhic Using Ac Dipoles.

Global linear coupling has been extensively studied in accelerators and several methods have been developed to compensate the coupling coefficient C using skew quadrupole families scans. However, scanning techniques can become very time consuming especially during the commissioning of an energy ramp. In this paper they illustrate a new technique to measure and compensate, in a single machine cycle, global linear coupling from turn-by-turn BPM data without the need of a skew quadrupole scan. The algorithm is applied to RHIC BPM data using AC dipoles and compared with traditional methods.
Date: June 26, 2006
Creator: Calaga, R. & Franchi, A. (Gsi), Tomas, R.(Cern)
Object Type: Article
System: The UNT Digital Library
Global and Local Coupling Compensation Experiments in Rhic Using Ac Dipoles. (open access)

Global and Local Coupling Compensation Experiments in Rhic Using Ac Dipoles.

Compensation of transverse coupling during the RHIC energy ramp has been proven to be non-trivial and tedious. The lack of accurate knowledge of the coupling sources has initiated several efforts to develop fast techniques using turn-by-turn BPM data to identify and compensate these sources. This paper aims to summarize the beam experiments performed to measure the coupling, matrix and resonance driving terms with the aid of RHIC ac dipoles at injection energy.
Date: June 26, 2006
Creator: Calaga, R. & Franchi, A. (Gsi), Tomas, R.(Cern)
Object Type: Article
System: The UNT Digital Library
Summary of Coupling and Tune Feedback Results During Rhic Run 6, and Possible Implications for Lhc Commissioning. (open access)

Summary of Coupling and Tune Feedback Results During Rhic Run 6, and Possible Implications for Lhc Commissioning.

Early efforts [1] to implement tune feedback during the acceleration ramp in RHIC were hampered by large betatron coupling, as well as the requirement for large dynamic range. Both problems have been addressed, the first by implementation of continuous measurement of coupling, and the second by the development of an improved analog front end. With these improvements, simultaneous coupling and tune feedback were successfully implemented for acceleration ramp development during RHIC Run 6. During the course of this work it became clear that direct excitation of the betatron resonances by high harmonics of the 60Hz power frequency was an obstacle to making the system fully operational. They report here on these results from RHIC Run 6, and implications for LHC commissioning.
Date: June 26, 2006
Creator: Cameron, P.; Dellapenna, A.; Hoff, L.; Luo, Y.; Marusic, A.; Ptitsyn, V. et al.
Object Type: Article
System: The UNT Digital Library
The Baytown Sun (Baytown, Tex.), Vol. 85, No. 227, Ed. 1 Monday, June 26, 2006 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 85, No. 227, Ed. 1 Monday, June 26, 2006

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: June 26, 2006
Creator: Cash, Wanda Garner
Object Type: Newspaper
System: The Portal to Texas History

[Man speaking at podium with NALEO emblem]

NALEO is the National Association of Latino Elected and Appointed Officials.
Date: June 26, 2006
Creator: Castillo, José L.
Object Type: Photograph
System: The Portal to Texas History
Parallel 3-D Space Charge Calculations in the Unified Accelerator Library. (open access)

Parallel 3-D Space Charge Calculations in the Unified Accelerator Library.

The paper presents the integration of the SIMBAD space charge module in the UAL framework. SIMBAD is a Particle-in-Cell (PIC) code. Its 3-D Parallel approach features an optimized load balancing scheme based on a genetic algorithm. The UAL framework enhances the SIMBAD standalone version with the interactive ROOT-based analysis environment and an open catalog of accelerator algorithms. The composite package addresses complex high intensity beam dynamics and has been developed as part of the FAIR SIS 100 project.
Date: June 26, 2006
Creator: D'imperio, N. L.; Luccio, A. U. & Malitsky, N.
Object Type: Article
System: The UNT Digital Library
Criticality Safety Evaluation of a LLNL Training Assembly for Criticality Safety (TACS) (open access)

Criticality Safety Evaluation of a LLNL Training Assembly for Criticality Safety (TACS)

Hands-on experimental training in the physical behavior of multiplying systems is one of ten key areas of training required for practitioners to become qualified in the discipline of criticality safety as identified in DOE-STD-1135-99, ''Guidance for Nuclear Criticality Safety Engineer Training and Qualification''. This document is a criticality safety evaluation of the training activities (or operations) associated with HS-3200, ''Laboratory Class for Criticality Safety''. These activities utilize the Training Assembly for Criticality Safety (TACS). The original intent of HS-3200 was to provide LLNL fissile material handlers with a practical hands-on experience as a supplement to the academic training they receive biennially in HS-3100, ''Fundamentals of Criticality Safety'', as required by ANSI/ANS-8.20-1991, ''Nuclear Criticality Safety Training''. HS-3200 is to be enhanced to also address the training needs of nuclear criticality safety professionals under the auspices of the NNSA Nuclear Criticality Safety Program.
Date: June 26, 2006
Creator: Heinrichs, D P
Object Type: Report
System: The UNT Digital Library
Commissioning of the Digital Transverse Bunch-by-Bunch Feedback System for the Tls. (open access)

Commissioning of the Digital Transverse Bunch-by-Bunch Feedback System for the Tls.

Multi-bunch instabilities degrade beam quality through increased beam emittance, energy spread and even beam loss. Feedback systems are used to suppress multi-bunch instabilities associated with the resistive wall of the beam ducts, cavity-like structures, and trapped ions. A new digital transverse bunch-by-bunch feedback system has recently been commissioned at the Taiwan Light Source, and has replaced the previous analog system. The new system has the advantages that it enlarges the tune acceptance and improves damping for transverse instability at high currents, such that top-up operation is achieved. After a coupled-bunch transverse instability was suppressed, more than 350 mA was successfully stored during preliminary commissioning. In this new system, a single feedback loop simultaneously suppresses both horizontal and vertical multi-bunch instabilities. Investigating the characteristics of the feedback loop and further improving the system performances are the next short-term goals. The feedback system employs the latest generation of field-programmable gate array (FPGA) processor to process bunch signals. Memory has been installed to capture up to 250 msec of bunch oscillation signal, considering system diagnostics suitable to support various beam physics studies.
Date: June 26, 2006
Creator: Hu, K. H.; Kuo, C. H.; Chou, P. J.; Lee, D.; Hsu, S. Y.; Chen, J. et al.
Object Type: Article
System: The UNT Digital Library
Acceleration of Polarized Protons in the AGS With Two Helical Partial Snakes. (open access)

Acceleration of Polarized Protons in the AGS With Two Helical Partial Snakes.

Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult: the depolarizing resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions and are not feasible in the AGS since straight sections are too short. Recently, two helical partial snakes with double pitch design have been built and installed in the AGS. With careful setup of optics at injection and along the ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances encountered during acceleration. This paper presents the accelerator setup and preliminary results.
Date: June 26, 2006
Creator: Huang, H.; Ahrens, L. A.; Bai, M.; Bravar, A.; Brown, K.; Courant, E. D. et al.
Object Type: Article
System: The UNT Digital Library
FURTHER DEVELOPMENT OF A LOW INDUCTANCE METAL VAPOR VACUUM ARC (LIZ-MEVVA) ION SOURCE. (open access)

FURTHER DEVELOPMENT OF A LOW INDUCTANCE METAL VAPOR VACUUM ARC (LIZ-MEVVA) ION SOURCE.

None
Date: June 26, 2006
Creator: Johnson, B. M.; Hershcovitch, A. & Al., Et
Object Type: Article
System: The UNT Digital Library
HIGH FIELD SOLENOID FOR MUON COOLING. (open access)

HIGH FIELD SOLENOID FOR MUON COOLING.

Magnets made with high-temperature superconducting (HTS) coils operating at low temperatures have the potential to produce extremely high fields for use in accelerators and beam lines. The specific application of interest that we are proposing is to use a very high field (of the order of 50 Tesla) solenoid to provide a very small beta region for the final stages of cooling for a muon collider. With the commercial availability of HTS conductor based on BSCCO technology with high current carrying capacity at 4.2 K, very high field solenoid magnets should be possible. In this paper we will evaluate the technical issues associated with building this magnet. In particular we address how to mitigate the high Lorentz stresses associated with this high field magnet.
Date: June 26, 2006
Creator: Kahn, S. A.; Alsharo'a, M.; Hanlet, P.; Johnson, R. P.; Kuchnir, M.; Newsham, F. et al.
Object Type: Article
System: The UNT Digital Library
Choice of Proton Driver Parameters for a Neutrino Factory (open access)

Choice of Proton Driver Parameters for a Neutrino Factory

We discuss criteria for designing an optimal 'green field' proton driver for a neutrino factory. The driver parameters are determined by considerations of space charge, power capabilities of the target, beam loading and available RF peak power. A neutrino factory may be the best experimental tool to unravel the physics involved in neutrino oscillation and CP violation phenomena [1]. To have sufficient neutrino flux for acceptable physics results within 5 years requires about 10{sup 22} protons on target per year, which corresponds to 1-4 MW of proton beam power from the proton driver depending on the beam energy. In the past, there were individual proposals from different laboratories of a particular design of proton driver capable of delivering beam power from 2 to 4 MW, without consistent attention paid to the needs or requirements from the downstream systems. In this study, we try to identify the requirements from those down stream systems first, then see whether it is possible to design a proton driver to meet those needs. Such a study will also assist site specific proposals to further improve on their designs to better serve the need of a proton driver for neutrino factory applications.
Date: June 26, 2006
Creator: Kirk, H. G.; Berg, J. S.; Fernow, R. C.; Gallardo, J. C.; Simos, N.; Weng, W. T. et al.
Object Type: Article
System: The UNT Digital Library
A 15-T Pulsed Solenoid for a High-Power Target Experiment (open access)

A 15-T Pulsed Solenoid for a High-Power Target Experiment

The MERIT experiment, to be run at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field. Here, we describe the design and initial performance of the 15-T, liquid-nitrogen-precooled, copper solenoid magnet.
Date: June 26, 2006
Creator: Kirk, H. G.; Efthymiopoulos, I.; Fabich, A.; Haug, R.; Titus, P.; McDonald, K. T. et al.
Object Type: Article
System: The UNT Digital Library
A Proof-of-Principal Experiment for a High-Power Target System (open access)

A Proof-of-Principal Experiment for a High-Power Target System

The MERIT experiment, to be run at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field. A muon collider or neutrino factory requires intense beams of muons, which are obtained from the decay of pions. Pion production by a proton beam is maximized by use of a high-Z target such as mercury. A liquid jet target has the advantages over a solid target that a flowing jet can readily remove heat and that it is immune to radiation damage. However the proton beam energy disrupts the jet and the system could be operationally unstable. Efficient capture of low-energy secondary pions (for transfer into the subsequent muon accelerator complex) requires that the target system be immersed in a strong magnetic field of solenoidal geometry. This magnetic field should stabilize the mercury flow in regions of nearly uniform field, but it perturbs the liquid metal jet as it enters the field. Hence, the behavior of the mercury …
Date: June 26, 2006
Creator: Kirk, H. G.; Samulyak, R.; Simos, N.; Tsang, T.; Efthymiopoulos, I.; Fabich, A. et al.
Object Type: Article
System: The UNT Digital Library
Optimizing the Dynamic Aperture for Triple Bend Achromatic Lattices. (open access)

Optimizing the Dynamic Aperture for Triple Bend Achromatic Lattices.

The Triple Bend Achromatic (TBA) lattice has the potential for lower natural emittance per period than the Double Bend Achromatic (DBA) lattice for high brightness light sources. However, the DBA has been chosen for 3rd generation light sources more often due to the higher number of undulator straight section available for a comparable emittance. The TBA has considerable flexibility in linear optics tuning while maintaining this emittance advantage. We have used the tune and chromaticity flexibility of a TBA lattice to minimize the lowest order nonlinearities to implement a 3rd order achromatic tune, while maintaining a constant emittance. This frees the geometric sextupoles to counter the higher order nonlinearities. This procedure is being used to improve the nonlinear dynamics of the TBA as a proposed lattice for NSLS-II facility. The flexibility of the TBA lattice will also provide for future upgrade capabilities of the beam parameters.
Date: June 26, 2006
Creator: Kramer, S. L. & Bengtsson, J.
Object Type: Article
System: The UNT Digital Library
COMPARISON OF DOUBLE BEND AND TRIPLE BEND ACHROMATIC LATTICE STRUCTURES AND NSLS-II. (open access)

COMPARISON OF DOUBLE BEND AND TRIPLE BEND ACHROMATIC LATTICE STRUCTURES AND NSLS-II.

The Double Bend Achromatic (DBA) and the Triple Bend Achromatic (TBA) lattice have been studied rather extensively for use for the NSLS-II storage ring. The advantage of the TBA compared to the DBA in terms of emittance per period is well known. However, the DBA has the advantage of greater number of ID straight sections for the users and maybe easier to tune the dispersive section for reduced chromatic sextupole strength. We present a comparison of these lattices based on optimization of the non-linear driving terms using high order achromatic cancellation of driving terms of the nonlinear lattice.
Date: June 26, 2006
Creator: Kramer, S. L.; Krinsky, S. & Bengtsson, J.
Object Type: Article
System: The UNT Digital Library
Vertical Beam Size Control in TLS and TPS (open access)

Vertical Beam Size Control in TLS and TPS

Vertical beam size control is an important issue in the light source operations. The horizontal-vertical betatron coupling and vertical dispersion were measured and corrected to small values in the TLS 1.5 GeV storage ring. Estimated beam sizes are compared with the measured values. By employing an effective transverse damping system, the vertical beam blow-up due to transverse coherent instabilities, such as the fast-ion beam instability, was suppressed. As a result, the light source is very stable. In NSRRC we are designing an ultra low emittance 3-GeV storage ring and its designed vertical beam size could be as small as a few microns. The ground and mechanic vibration effects, and coherent instabilities could spoil the expected photon brightness due to blow-up of the vertical beam size if not well taken care of. The contributions of these effects to vertical beam size increase will be evaluated and the counter measures to minimize them will be proposed and reported in this paper.
Date: June 26, 2006
Creator: Kuo, C. C.; Chen, J. R.; Chou, P. J.; Chang, H. P.; Hsu, K. T.; Luo, G. H. et al.
Object Type: Article
System: The UNT Digital Library
DENSITY-FUNCTIONAL CALCULATIONS OF ALPHA-Pu-Ga (Al) ALLOYS (open access)

DENSITY-FUNCTIONAL CALCULATIONS OF ALPHA-Pu-Ga (Al) ALLOYS

None
Date: June 26, 2006
Creator: Landa, A; Soderlind, P & Vitos, L
Object Type: Article
System: The UNT Digital Library
ALE3D Simulation of Heating and Violence in a Fast Cookoff Experiment with LX-10 (open access)

ALE3D Simulation of Heating and Violence in a Fast Cookoff Experiment with LX-10

We performed a computational and experimental analysis of fast cookoff of LX-10 (94.7% HMX, 5.3% Viton A) confined in a 2 kbar steel tube with reinforced end caps. A Scaled-Thermal-Explosion-eXperiment (STEX) was completed in which three radiant heaters were used to heat the vessel until ignition, resulting in a moderately violent explosion after 20.4 minutes. Thermocouple measurements showed tube temperatures as high as 340 C at ignition and LX-10 surface temperatures as high as 279 C, which is near the melting point of HMX. Three micro-power radar systems were used to measure mean fragment velocities of 840 m/s. Photonics Doppler Velocimeters (PDVs) showed a rapid acceleration of fragments over 80 {micro}s. A one-dimensional ALE3D cookoff model at the vessel midplane was used to simulate the heating, thermal expansion, LX-10 decomposition composition, and closing of the gap between the HE (High Explosive) and vessel wall. Although the ALE3D simulation terminated before ignition, the model provided a good representation of heat transfer through the case and across the dynamic gap to the explosive.
Date: June 26, 2006
Creator: McClelland, M. A.; Maienschein, J. L.; Howard, W. M.; Nichols, A. L.; deHaven, M. R. & Strand, O. T.
Object Type: Article
System: The UNT Digital Library
STATUS OF FAST IR ORBIT FEEDBACK AT RHIC. (open access)

STATUS OF FAST IR ORBIT FEEDBACK AT RHIC.

To compensate modulated beam-beam offsets caused by mechanical vibrations of IR triplet quadrupoles at frequencies around 10 Hz, a fast IR orbit feedback system has been developed. We report design considerations and recent status of the system.
Date: June 26, 2006
Creator: Montag, C.; Cupolo, J.; Glenn, J.; Litvinenko, V.; Marusic, A.; Meng, W. et al.
Object Type: Article
System: The UNT Digital Library