1500 MHZ Passive SRF Cavity for Bunch Lengthening in the NSLS-II Storage Ring (open access)

1500 MHZ Passive SRF Cavity for Bunch Lengthening in the NSLS-II Storage Ring

NSLS-II is a new ultra-bright 3 GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. Ion clearing gaps are required to suppress ion effects on the beam. The natural bunch length of 3mm is planned to be lengthened by means of a third harmonic cavity in order to increase the Touschek limited lifetime. After an extensive investigation of different cavity geometries, a passive, superconducting two-cell cavity has been selected for prototyping. The cavity is HOM damped with ferrite absorbers on the beam pipes. The two-cell cavity simplifies the tuner design, compared to having two independent cells. Tradeoffs between the damping of the higher order modes, thermal isolation associated with the large beam tubes, and overall cavity length are described. A copper prototype has been constructed, and measurements of fundamental and higher order modes will be compared to calculated values.
Date: May 4, 2009
Creator: Yanagisawa,T.; Rose, J.; Grimm, T. & Bogle, A.
Object Type: Article
System: The UNT Digital Library
2007 Idaho National Laboratory Annual Illness and Injury Surveillance Report (open access)

2007 Idaho National Laboratory Annual Illness and Injury Surveillance Report

The U.S. Department of Energy’s (DOE) commitment to assuring the health and safety of its workers includes the conduct of illness and injury surveillance activities that provide an early warning system to detect health problems among workers. The Illness and Injury Surveillance Program monitors illnesses and health conditions that result in an absence, occupational injuries and illnesses, and disabilities and deaths among current workers.
Date: May 4, 2009
Creator: United States. Department of Energy. Office of Health, Safety, and Security.
Object Type: Report
System: The UNT Digital Library
2007 Idaho National Laboratory Annual Illness and Injury Surveillance Report (open access)

2007 Idaho National Laboratory Annual Illness and Injury Surveillance Report

The U.S. Department of Energy’s (DOE) commitment to assuring the health and safety of its workers includes the conduct of illness and injury surveillance activities that provide an early warning system to detect health problems among workers. The Illness and Injury Surveillance Program monitors illnesses and health conditions that result in an absence, occupational injuries and illnesses, and disabilities and deaths among current workers.
Date: May 4, 2009
Creator: U.S. Department of Energy, Office of Health, Safety, and Security
Object Type: Report
System: The UNT Digital Library
The 2009 Influenza Pandemic: Selected Legal Issues (open access)

The 2009 Influenza Pandemic: Selected Legal Issues

Recent human cases of infection with a novel influenza A(H1N1) virus have been identified both internationally and in the United States. Since there has been human to human transmission and the new virus has the potential to become pandemic, it is timely to examine legal issues surrounding this emerging public health threat. This report will provide a brief overview of selected legal issues.
Date: May 4, 2009
Creator: Swendiman, Kathleen S. & Jones, Nancy L.
Object Type: Report
System: The UNT Digital Library
3D Simulations of Secondary Electron Generation and Transport in a Diamond Electron Beam Amplifier (open access)

3D Simulations of Secondary Electron Generation and Transport in a Diamond Electron Beam Amplifier

The Relativistic Heavy Ion Collider (RHIC) contributes fundamental advances to nuclear physics by colliding a wide range of ions. A novel electron cooling section, which is a key component of the proposed luminosity upgrade for RHIC, requires the acceleration of high-charge electron bunches with low emittance and energy spread. A promising candidate for the electron source is the recently developed concept of a high quantum efficiency photoinjector with a diamond amplifier. To assist in the development of such an electron source, we have implemented algorithms within the VORPAL particle-in-cell framework for modeling secondary electron and hole generation, and for charge transport in diamond. The algorithms include elastic, phonon, and impurity scattering processes over a wide range of charge carrier energies. Results from simulations using the implemented capabilities will be presented and discussed.
Date: May 4, 2009
Creator: Busby, R.; Rao, T.; Dimitrov, D. A.; Cary, J. R.; Ben-Zvi, Ilan; Chang, X. et al.
Object Type: Article
System: The UNT Digital Library
Accelerator Physics Challenges for the NSLS-II Project (open access)

Accelerator Physics Challenges for the NSLS-II Project

The NSLS-II is an ultra-bright synchrotron light source based upon a 3-GeV storage ring with a 30-cell (15 super-period) double-bend-achromat lattice with damping wigglers used to lower the emittance below 1 nm. In this paper, we discuss the accelerator physics challenges for the design including: optimization of dynamic aperture; estimation of Touschek lifetime; achievement of required orbit stability; and analysis of ring impedance and collective effects.
Date: May 4, 2009
Creator: Krinsky, S.
Object Type: Article
System: The UNT Digital Library
AGS Fast spin resonance jump, magnets and power supplies (open access)

AGS Fast spin resonance jump, magnets and power supplies

In order to cross more rapidly the 82 weak spin resonances caused by the horizontal tune and the partial snakes, we plan to jump the horizontal tune 82 times during the acceleration of polarized protons. The current in the magnets creating this tune jump will rise in 100 {micro}s, hold flat for about 4 ms and fan to zero in 100 {micro}s. Laminated beam transport quadrupole magnets have been recycled by installing new two turn coils and longitudinal laminated pole tip shims that reduce inductance and power supply current. The power supply uses a high voltage capacitor discharge to raise the magnet current, which is then switched to a low voltage supply, and then the current is switched back to the high voltage capacitor to zero the current. The current in each of the magnet pulses must match the order of magnitude change in proton momentum during the acceleration cycle. The magnet, power supply and operational experience are described.
Date: May 4, 2009
Creator: Glenn,J.W.; Huang, H.; Liaw, C. J.; Marneris, I.; Meng, W.; Mi, J. L. et al.
Object Type: Article
System: The UNT Digital Library
Alternative Designs for the NSLS-II Injection Straight Section (open access)

Alternative Designs for the NSLS-II Injection Straight Section

Brookhaven National Laboratory (BNL) is developing a state-of-the-art 3 GeV synchrotron light source, the NSLS-II [1]. The 9.3 meter-long injection straight section of its storage ring now fits a conventional injection set-up consisting of four kickers producing a closed bump, together with a DC septum and a pulsed septum. In this paper, we analyze an alternative option based on injection via a pulsed sextupole magnet. We discuss the dynamics of the injected and stored beams and, subsequently, the magnet's specifications and tolerances. We conclude by summarized the advantages and drawbacks of each injection scheme.
Date: May 4, 2009
Creator: Shaftan,T.; Heese, R.; Weihreter, E.; Willeke, F.; Rehak, M.; Meier, R. et al.
Object Type: Article
System: The UNT Digital Library
Analysis of the transverse SPS beam coupling impedance with short and long bunches (open access)

Analysis of the transverse SPS beam coupling impedance with short and long bunches

The upgrade of the CERN Large Hadron Collider (LHC) would require a four- to five-fold increase of the single bunch intensity presently obtained in the Super Proton Synchrotron (SPS). Operating at such high single bunch intensities requires a detailed knowledge of the sources of SPS beam coupling impedance, so that longitudinal and transverse impedance reduction campaigns can be planned and performed effectively if needed. In this paper, the transverse impedance of the SPS is studied by injecting a single long bunch into the SPS, and observing its decay without RF. Longer bunches allow for higher frequency resolution of the longitudinal and transverse bunch spectra acquired with strip line couplers connected to a fast data acquisition. It also gives access to the frequency content of the transverse impedance. Results from measurements with short and long bunches in the SPS performed in 2008 are compared with simulations.
Date: May 4, 2009
Creator: Salvant, B.; Calaga, R.; De Maria, R.; Arduini, G.; Burkhardt, H.; Damerau, H. et al.
Object Type: Article
System: The UNT Digital Library
Analytical studies of coherent electron cooling (open access)

Analytical studies of coherent electron cooling

Under certain assumptions and simplifications, we studied a few physics processes of Coherent Electron Cooling using analytical approach. In the modulation process, the effect due to merging the ion beam with the electron beam is studied under single kick approximation. In the free electron laser (FEL) amplifier, we studied the amplification of the electron density modulation using 1D analytical approach. Both the electron charge density and the phase space density are derived in the frequency domain. The solutions are then transformed into the space domain through Fast Fourier Transformation (FFT).
Date: May 4, 2009
Creator: Wang, G.; Blaskiewicz, M. & Litvinenko, V. N.
Object Type: Article
System: The UNT Digital Library
Banking and Financial Infrastructure Continuity: Pandemic Flu, Terrorism, and Other Challenges (open access)

Banking and Financial Infrastructure Continuity: Pandemic Flu, Terrorism, and Other Challenges

This report outlines the financial sector's recovery plans for two kinds of disasters: the inability to conduct transactions and large losses of asset value. The basic function of the payment system is carried out by banks, and monetary policy affects banks immediately. Because brokers, exchanges, secondary market facilities, and insurance companies carry out crucial financial functions, their regulators and trade associations are involved in continuity of operations planning for contingencies.
Date: May 4, 2009
Creator: Weiss, N. E.
Object Type: Report
System: The UNT Digital Library
Beam Based Calibration of Slow Orbit Bump in the NSLS Booster (open access)

Beam Based Calibration of Slow Orbit Bump in the NSLS Booster

The orbit bumps in NSLS booster are used to move the beam orbit within 2mm of the extraction septum aperture on a time scale of millisecond at extraction in order to reduce the requirement on the amplitude of the fast extraction kicker. This may cause charge losses since before extraction, the beam stays on the distorted orbit for thousands of revolutions. In order to find the optimal orbit bump setpoint, which brings the maximum distortion at the extraction position and minimum distortions everywhere else, we developed an extraction model and performed an experiment to validate it. Afterwards, the model was applied to optimize the extraction process.
Date: May 4, 2009
Creator: Yang, X.; Shaftan, T. & Rose, J.
Object Type: Article
System: The UNT Digital Library
Beam commissioning of the RFQ for the RHIC-EBIS project (open access)

Beam commissioning of the RFQ for the RHIC-EBIS project

Beam commissioning of a new 4 rod RFQ has started at Brookhaven National Laboratory (BNL). The RFQ will accelerate intense heavy ion beams provided by an Electron Beam ion Source (EBIS) up to 300 keV/u. The RFQ will accelerate a range of Q/M from 1 to 1/6, and the accelerated beam will be finally delivered to the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory (NSRL). The first beam was successfully accelerated and the bunch structures of He{sup +} and Cu{sup 10+} beams were measured. The further beam tests are in progress.
Date: May 4, 2009
Creator: Okamura,M.; Alessi, J.; Beebe, E.; Lodestro, V.; Pikin, A.; Ritter, J. et al.
Object Type: Article
System: The UNT Digital Library
Beam dynamics and expected RHIC performance with 56MHz RF upgrade (open access)

Beam dynamics and expected RHIC performance with 56MHz RF upgrade

An upgrade of the RHIC storage RF system with a superconducting 56 MHz cavity was recently proposed. This upgrade will provide a significant increase in the acceptance of the RHIC 197 MHz storage RF bucket. This paper summarizes simulations of beam evolution due to intra-beam scattering (IBS) for beam parameters expected with the 56 MHz SRF cavity upgrade. Expected luminosity improvements are shown for Au ions at 100 GeV/nucleon and protons at 250 GeV.
Date: May 4, 2009
Creator: Fedotov, A. V. & Ben-Zvi, Ilan
Object Type: Article
System: The UNT Digital Library
Beam emittance measurements in RHIC (open access)

Beam emittance measurements in RHIC

The RHIC proton polarimeters can operate in scanning mode, giving polarization profiles and transverse beam intensity profile (beam emittance) measurements. The polarimeters function as wire scanners, providing a very good signal/noise ratio and high counting rate. This allows accurate bunch-by-bunch emittance measurements during fast target sweeps (<1 s) through the beam. Very thin carbon strip targets make these measurements practically non-destructive. Bunch by bunch emittance measurements are a powerful tool for machine set-up; in RHIC, individual proton beam transverse emittances can only be measured by CNI polarimeter scans. We discuss the consistency of these measurements with Ionization Profile Monitors (IPMs) and vernier scan luminosity measurements. Absolute accuracy limitations and cross-calibration of different techniques are also discussed.
Date: May 4, 2009
Creator: Zelenski,A.; Bazilevsky, A.; Bunce, G.; Gill, R.; Huang, H.; Makdisi, Y. et al.
Object Type: Article
System: The UNT Digital Library
Beam Loss Monitors in the NSLS Storage Rings (open access)

Beam Loss Monitors in the NSLS Storage Rings

Beam loss monitors (BLM) have been used for more than two decades in the VUV ring at the NSLS. These have proved useful for optimizing injection and operation of the ring. Recently similar monitors have been installed in the X-ray ring and are being used to better understand injection, as well as operation of the ring. These units have been compared with the Bergoz BLMs, which have been mostly useful for understanding operating beam losses.
Date: May 4, 2009
Creator: Kramer, S. L. & Fedurin, M.
Object Type: Article
System: The UNT Digital Library
Beam Transport and Diagnostics for the NSLS-II Injection System (open access)

Beam Transport and Diagnostics for the NSLS-II Injection System

The NSLS-II is a state of the art 3 GeV synchrotron light source being developed at BNL. The injection system will consist of a 200 MeV linac, 3 GeV booster synchrotron, and associated transfer lines. The transport lines between the linac and booster (LtB) and the booster and storage ring (BSR) must satisfy a number of requirements. In addition to transporting the beam while maintaining the beam emittance, these lines must allow for commissioning, provide appropriate diagnostics, allow for the appropriate safety devices and in the case of the BSR line, provide a stable beam for top off injection. Appropriate diagnostics are also necessary in the linac and booster to complement the measurements in the transfer lines and to allow for fast commissioning. In this paper we discuss the design of the transfer lines for the NSLSII along with the incorporated diagnostics and safety systems. Necessary diagnostics in the linac and booster are also discussed.
Date: May 4, 2009
Creator: Fliller, R., III; Alforque, R.; Heese, R.; Meier, R.; Rose, J.; Shaftan, T. et al.
Object Type: Article
System: The UNT Digital Library
Beta* and beta-waist measurement and control at RHIC (open access)

Beta* and beta-waist measurement and control at RHIC

During the course of last RHIC runs the beta-functions at the collision points ({beta}*) have been reduced gradually to 0.7m. In order to maximize the collision luminosity and ensure the agreement of the actual machine optics with the design one, more precise measurements and control of {beta}* value and {beta}-waist location became necessary. The paper presents the results of the implementation of the technique applied in last two RHIC runs. The technique is based on well-known relation between the tune shift and the beta function and involves precise betatron tune measurements using BBQ system as well as specially developed knobs for {beta}-waist location control.
Date: May 4, 2009
Creator: Ptitsyn, V.; Della Penna, A.; Litvinenko, V. N.; Malitsky, N. & Satogata, T.
Object Type: Article
System: The UNT Digital Library
BNL 703 MHz SRF cryomodule demonstration (open access)

BNL 703 MHz SRF cryomodule demonstration

This paper will present the preliminary results of the testing of the 703 MHz SRF cryomodule designed for use in the ampere class ERL under construction at Brookhaven National Laboratory. The preliminary cavity tests, carried out at Thomas Jefferson Laboratory, demonstrated cavity performance of 20 MV/m with a Qo of 1 x 10{sup 10}, results we expect to reproduce in the horizontal configuration. This test of the entire string assembly will allow us to evaluate all of the additional cryomodule components not previously tested in the VTA and will prepare us for our next milestone test which will be delivery of electrons from our injector through the cryomodule to the beam dump. This will also be the first demonstration of an accelerating cavity designed for use in an ampere class ERL, a key development which holds great promise for future machines.
Date: May 4, 2009
Creator: Burrill, A.; Ben-Zvi, Ilan; Calaga, R.; Dalesio, L.; Dottavio, T.; Gassner, D. et al.
Object Type: Article
System: The UNT Digital Library
The booster to AGS transfer line: comparison between model and measurements (open access)

The booster to AGS transfer line: comparison between model and measurements

The Booster to AGS (BtA) transfer line was to match both ions and protons into the AGS lattice. For proton beam operation the only constraint on the optics is to define a match to the AGS lattice. For ion operation there are additional constraints introduced by a stripping foil in the upstream part of the transfer line. For polarized proton operation there is the complication that the AGS lattice is distorted by the presence of two partial snake magnets. In the 2008 polarized proton run it was observed that there was a significant optical injection mismatch. Beam experiments were conducted that showed disagreement with the model of the BtA line. In addition, these studies revealed some minor problems with the instrumentation in the line. A new model and more reliable measurements of the transfer line magnet currents have been implemented. Another series of experiments was conducted to test these modifications and to collect a more complete set of data to allow better understanding of the beam dynamics during the transfer and better understanding of the instrumentation. In this paper we will present the results of these experiments and the comparison to the new model of the BtA.
Date: May 4, 2009
Creator: Brown, K. A.; Ahrens, L.; Bonati, R.; Gassner, D.; Glenn, W.; Huang, H. et al.
Object Type: Article
System: The UNT Digital Library
BPM Button Optimization to Minimize Distortion Due to Trapped Mode Heating (open access)

BPM Button Optimization to Minimize Distortion Due to Trapped Mode Heating

The outer circumference of a BPM button and the inner circumference of the button housing comprise a transmission line. This transmission line typically presents an impedance of a few tens of ohms to the beam, and couples very weakly to the 50 ohm coaxial transmission line that comprises the signal path out of the button. The modes which are consequently excited and trapped often have quality factors of several hundred, permitting resonant excitation by the beam. The thermal distortion resulting from trapped mode heating is potentially problematic for achieving the high precision beam position measurements needed to provide the sub-micron beam position stability required by light source users. We present a button design that has been optimized via material selection and component geometry to minimize both the trapped mode heating and the resulting thermal distortion.
Date: May 4, 2009
Creator: Cameron, P.; Blednyk, A.; Kosciuk, B.; Pinayev, I.; Ravindranath, I. & Singh, O
Object Type: Article
System: The UNT Digital Library
Coherent electron cooling (open access)

Coherent electron cooling

Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.
Date: May 4, 2009
Creator: Litvinenko,V.
Object Type: Article
System: The UNT Digital Library
Command Line Interface to Tracy Library (open access)

Command Line Interface to Tracy Library

We describe a set of tools that interface to the Tracy particle tracking library. The state of the machine including misalignments, multipole errors and corrector settings is captured in a 'flat' file, or 'machine' file. There are three types of tools designed around this flat file: (1) flat file creation tools. (2) flat file manipulation tools. (3) tracking tools. We describe the status of these tools, and give some examples of how they have been used in the design process for NSLS-II.
Date: May 4, 2009
Creator: Nash,B.
Object Type: Article
System: The UNT Digital Library
Commissioning of the new AGS MMPS transformers (open access)

Commissioning of the new AGS MMPS transformers

The Brookhaven AGS Main Magnet Power Supply (MMPS) is a thyristor control supply rated at 5500 Amps. +/-9000 Volts. The peak magnet power is 50 MWatts. The power supply is fed from a motor/generator manufactured by Siemens. During rectify and invert operation the P Bank power supplies are used. During the flattops the F Bank power supplies are used. The P Bank power supplies are fed from two 23 MVA transformers and the F Bank power supplies are fed from two 5.3 MYA transformers. The fundamental frequency of the F Bank power supplies is 1440 Hz, however the fundamental frequency of the P banks was 720 Hz. It was very important to reduce the ripple during rectify to improve polarized proton operations. For this reason and also because the original transformers were 45 years old we replaced these transformers with new ones and we made the fundamental frequency of both P and F banks 1440 Hz. This paper will highlight the major hurdles that were involved during the installation of the new transformers. It will present waveforms while running at different power levels up to 6MW full load. It will show the transition from the F-Bank power supplies to the …
Date: May 4, 2009
Creator: Bajon,E.; Badea, V. S.; Bannon, M.; Bonati, R.; Marneris, I. M.; Porqueddu, r. et al.
Object Type: Article
System: The UNT Digital Library