162 Matching Results

Search Results

Advanced search parameters have been applied.

Physics of Ultra-Peripheral Nuclear Collisions

Description: Moving highly-charged ions carry strong electromagnetic fields which act as a field of photons. In collisions at large impact parameters, hadronic interactions are not possible, and the ions interact through photon-ion and photon-photon collisions known as ultra-peripheral collisions (UPC). Hadron colliders like the Relativistic Heavy Ion Collider (RHIC), the Tevatron and the Large Hadron Collider (LHC) produce photonuclear and two-photon interactions at luminosities and energies beyond that accessible elsewhere; the LHC will reach a {gamma}p energy ten times that of the Hadron-Electron Ring Accelerator (HERA). Reactions as diverse as the production of anti-hydrogen, photoproduction of the {rho}{sup 0}, transmutation of lead into bismuth and excitation of collective nuclear resonances have already been studied. At the LHC, UPCs can study many types of ''new physics''.
Date: February 2, 2005
Creator: Bertulani, Carlos A.; Klein, Spencer R. & Nystrand, Joakim
Partner: UNT Libraries Government Documents Department

Leakage Rates for Cryolab Valves

Description: This note summarizes a brief study on the leakage rates of cryolab valves due to the failure of the valve packings. The {Delta}r gap between the shaft and the packing, the fluid (Ar or N2), the {Delta}p (atm) between the fluid and atmosphere, and the initial temperature of the escaping gas were varied to determine the resulting leakage rate. The heat leak in watts required to vaporize the liquid which provides the indicated flow rates is also included in the results. The dimensions used in the calculations were acquired over the telephone and/or found on the enclosed drawing from Cryolab. There is no implication that Cryolab was any better or worse than other valve manufacturers. They were kind enough to provide the detail needed for this study. The fluid properties were found in Ar and N2 Property handbooks. The results of this study are shown graphically and listed on accompanying spread sheets. The spread sheets and graphs can be found on the disc JW4 in the MassFlow folder.
Date: November 2, 1988
Creator: Wendlandt, J.M.
Partner: UNT Libraries Government Documents Department

Proceedings of RIKEN BNL Research Center Workshop: Brookhaven Summer Program on Nucleon Spin Physics

Description: Understanding the structure of the nucleon is of fundamental importance in sub-atomic physics. Already the experimental studies on the electro-magnetic form factors in the 1950s showed that the nucleon has a nontrivial internal structure, and the deep inelastic scattering experiments in the 1970s revealed the partonic substructure of the nucleon. Modern research focuses in particular on the spin and the gluonic structure of the nucleon. Experiments using deep inelastic scattering or polarized p-p collisions are carried out in the US at the CEBAF and RHIC facilities, respectively, and there are other experimental facilities around the world. More than twenty years ago, the European Muon Collaboration published their first experimental results on the proton spin structure as revealed in polarized deep inelastic lepton-nucleon scattering, and concluded that quarks contribute very little to the proton's spin. With additional experimental and theoretical investigations and progress in the following years, it is now established that, contrary to naive quark model expectations, quarks and anti-quarks carry only about 30% of the total spin of the proton. Twenty years later, the discovery from the polarized hadron collider at RHIC was equally surprising. For the phase space probed by existing RHIC experiments, gluons do not seem to contribute any to the proton's spin. To find out what carries the remaining part of proton's spin is a key focus in current hadronic physics and also a major driving force for the new generation of spin experiments at RHIC and Jefferson Lab and at a future Electron Ion Collider. It is therefore very important and timely to organize a series of annual spin physics meetings to summarize the status of proton spin physics, to focus the effort, and to layout the future perspectives. This summer program on 'Nucleon Spin Physics' held at Brookhaven National Laboratory (BNL) on July 14-27, ...
Date: August 2, 2011
Creator: Aschenauer, A.; Qiu, Jianwei; Vogelsang, W. & Yuan, F.
Partner: UNT Libraries Government Documents Department

4X6" Rotary Bayonet LN2 Test Fill

Description: This engineering note describes a test fill of the 4-inch x 6-inch rotary bayonet test fixture with LN{sub 2}. This test verifies the operation of valves on the fixture, and checks for proper construction/insulation. Further cold testing is imminent (with rotation and moment loading of the bayonet) after proper construction is verified and the test fixture is accepted. While this test fixture is a pressure vessel (4-inch), it does not require special safety treatment because it is under 6-inch in diameter. Flow capacity calculations were done to insure that the relief valve chosen would be capable of handling fire/loss of vacuum conditions. The D-Zero Safety Committee Chairman was notified of this testing.
Date: August 2, 1988
Creator: Fitzpatrick, J.B.
Partner: UNT Libraries Government Documents Department

D-0 North End Cap Calorimeter Cold Test Results

Description: The North endcap calorimeter vessel was recieved on July 1, 1990. A cooldown of the pressure vessel with liquid nitrogen was performed on July 10-11 to check the vessel's integrity. With the pressure vessel cold, the insulating vacuum was monitored for leaks. Through out the testing, the insulating vacuum remained good and the vessel passed the test. The cold test was carried out per the procedures of D-Zero engineering note 3740.220-EN-250. The test was very similar to the cold test performed on the Central Calorimeter in October of 1987. Reference D-Zero engineering notes 3740.210-EN-122, 3740.000-EN107, and 3740.210-EN-110 for information about the CC cold test. The insulating vacuum space was pumped on while equipment was being connected to the pressure vessel. Two hours after starting to pump with the blower the vacuum space pressure was at about 210 microns. Pumping on the vacuum space for the next 15 hours showed no progress and a leak detector was connected to the pumping line. A leak check showed a leak in a thermocouple feedthru on the vacuum space relief plate. After fixing the leak, the pressure dropped to 16 microns in less than one hour. A rate of rise test was performed starting at a pressure of 13 microns. The pressure rose to 39 microns within 8 minutes and then only rose to 43 microns in 2.5 hours (1.6 microns/hour). After all connections were made to the pressure vessel, a vacuum pump with an estimated effective pumping speed of about 70 scfm was valved on. The lowest pressure achieved after 2 days of pumping was 80 microns. Valving out the pump for 30 minutes resulted in a 5 micron per minute rate of rise. The rate of rise was considered acceptable since there were known leak paths through the bolts of the signal ...
Date: August 2, 1990
Creator: Michael, J.
Partner: UNT Libraries Government Documents Department

MH Test Filler Force Limitations

Description: The OH modules for the DO end calorimeter are being tested by supporting a load to simulate the MH, IH, and EM modules. This test structure, the MH filler, is inserted into the previously assembled OH modules, and then loaded with hydraulic jacks. The maximum test load applied by the jacks is 78,600 lb, which is via the two downstream jacks at 130% of the nominal load. Bill Cooper's memo of 9/10/90 is include as appendix C. This note presents calculations for the AISC maximum allowable stresses/loads of the various parts of the testing assembly. Furthermore, calculations show that the actual test load is less than the AISC allowable.
Date: October 2, 1990
Creator: Primdahl, K. A.
Partner: UNT Libraries Government Documents Department

Sorting chromatic sextupoles for easily and effectively correcting second order chromaticity in the Relativistic Heavy Ion Collider

Description: Based on the contributions of the chromatic sextupole families to the half-integer resonance driving terms, we discuss how to sort the chromatic sextupoles in the arcs of the Relativistic Heavy Ion Collider (RHIC) to easily and effectively correct the second order chromaticities. We propose a method with 4 knobs corresponding to 4 pairs of chromatic sextupole families to online correct the second order chromaticities. Numerical simulation justifies this method, showing that this method reduces the unbalance in the correction strengths of sextupole families and avoids the reversal of sextupole polarities. Therefore, this method yields larger dynamic apertures for the proposed RHIC 2009 100GeV polarized proton run lattices.
Date: January 2, 2009
Creator: Luo,Y.; Tepikian, S.; Fischer, W.; Robert-Demolaize, G. & Trbojevic, D.
Partner: UNT Libraries Government Documents Department

Superconducting Storage Cavity for RHIC

Description: This document provides a top-level description of a superconducting cavity designed to store hadron beams in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It refers to more detailed documents covering the various issues in designing, constructing and operating this cavity. The superconducting storage cavity is designed to operate at a harmonic of the bunch frequency of RHIC at a relatively low frequency of 56 MHz. The current storage cavities of RHIC operate at 197 MHz and are normal-conducting. The use of a superconducting cavity allows for a high gap voltage, over 2 MV. The combination of a high voltage and low frequency provides various advantages stemming from the resulting large longitudinal acceptance bucket.
Date: January 2, 2009
Creator: Ben-Zvi,I.
Partner: UNT Libraries Government Documents Department

Introduction to Electroweak Symmetry Breaking

Description: The Standard Model (SM) is the backbone of elementary particle physics-not only does it provide a consistent framework for studying the interactions of quark and leptons, but it also gives predictions which have been extensively tested experimentally. In these notes, I review the electroweak sector of the Standard Model, discuss the calculation of electroweak radiative corrections to observables, and summarize the status of SM Higgs boson searches. Despite the impressive experimental successes, however, the electroweak theory is not completely satisfactory and the mechanism of electroweak symmetry breaking is untested. I will discuss the logic behind the oft-repeated statement: 'There must be new physics at the TeV scale'. These lectures reflect my strongly held belief that upcoming results from the LHC will fundamentally change our understanding of electroweak symmetry breaking. In these lectures, I review the status of the electroweak sector of the Standard Model, with an emphasis on the importance of radiative corrections and searches for the Standard Model Higgs boson. A discussion of the special role of the TeV energy scale in electroweak physics is included.
Date: October 2, 2008
Creator: Dawson,S.
Partner: UNT Libraries Government Documents Department

HEAVY ION COLLISIONS AND NEW FORMS OF MATTER

Description: I discuss forms of high energy density matter in QCD. These include the Color Glass Condensate, the Glasma and the Quark Gluon Plasma. These all might be studied in ultra-relativistic heavy ion collisions, and the Color Glass Condensate might also be probed in electron-hadron collisions. I present the properties of such matter, and some aspects of what is known of their properties.
Date: July 2, 2007
Creator: MCLERRAN,L.
Partner: UNT Libraries Government Documents Department

Dynamic aperture evaluation of the proposed lattices for the RHIC 2009 polarized proton run

Description: In the article we evaluate the dynamic apertures of the proposed lattices for the coming Relativistic Heavy Ion Collider (RHIC) 2009 polarized proton (pp) 100 GeV and 250 GeV runs. One goal of this study is to find out the appropriate {beta}* for the coming 2009 pp runs. Another goal is to study the effect of second order chromaticity correction in the RHIC pp runs.
Date: January 2, 2009
Creator: Luo,Y.; Bai, M.; Beebe-Wang, J.; Fischer, W.; Montag, C.; Robert-Demolaize, G. et al.
Partner: UNT Libraries Government Documents Department

Effects of Booster Scraping in Polarized Proton Runs 2006 and 2008

Description: Effects of the Booster vertical scraping on the RHIC beam polarization, the RHIC beam emittance, and on the Booster to AGS transfer efficiency and AGS transmission as well, are further studied. In [1], the strong dependence of the RHIC beam polarization and emittance on bunch intensity in proton run 2008 (pp08) is compared with the proton run 2006 (pp06), where the dependence is much weaker. The setting in the AGS Booster, mainly the vertical scraping, is suspected to having played a role in the different patterns in the two runs. In this note, we further study the effects of the Booster vertical scraping on the RHIC beam polarization, and on the RHIC beam emittance as well. With the improvement of the RHIC bunch intensity in mind, the Booster scraping effects on the Booster to AGS transfer (BtA) efficiency and the AGS transmission are also studied. For simplicity and to be more useful, only the RHIC fills after the one-week shutdown in pp06 and the fills using the AGS User 2 in pp08 are shown. For these fills, the machine settings in AGS are similar in pp06 and pp08 runs. Furthermore, this setting might be used for next polarized proton run, at least at the beginning of the run.
Date: January 2, 2009
Creator: Zhang,S.Y.; Ahrens, L.; Huang, H. & Zeno, K.
Partner: UNT Libraries Government Documents Department

Enhancing the CDF's B physics program with a faster data acquisition system.

Description: The physics program of Run II at the Tevatron includes precision electroweak measurements such as the determination of the top quark and W boson masses; bottom and charm physics including the determination of the B{sub s} and D{sup 0} mixing parameters; studies of the strong interaction; and searches for the Higgs particle, supersymmetric particles, hidden space-time dimensions and quark substructure. All of these measurements benefit from a high-resolution tracking detector. Most of them rely heavily on the efficient identification of heavy flavored B hadrons by detection of displaced secondary vertices, and are enhanced by the capability to trigger on tracks not coming from the primary vertex. This is uniquely provided by CDF's finely-segmented silicon detectors surrounding the interaction region. Thus CDF experiment's physics potential critically depends on the performance of its silicon detectors. The CDF silicon detectors were designed to operate up to 2-3 fb{sup -1} of accumulated pji collisions, with an upgrade planned thereafter. However, the upgrade project was canceled in 2003 and Run II has been extended through 2011, with an expected total delivered integrated luminosity of 12 fb{sup -1} or more. Several preventive measures were taken to keep the original detector operational and maintain its performance. The most important of these are the decrease in the operating temperature of the detector, which reduces the impact of radiation exposure, and measures to minimize damage due to integrated radiation dose, thermal cycles, and wire bond resonance conditions. Despite these measures the detectors operating conditions continue to change with issues arising from radiation damage to the sensors, aging infrastructure and electronics. These, together with the basic challenges posed by the inaccessibility of the detector volume and large number (about 750 thousand) of readout channels, make the silicon detector operations the single most complex and high priority job in the CDF ...
Date: March 2, 2011
Creator: Maksimovic, Dr. Petar
Partner: UNT Libraries Government Documents Department

Modification of Particle Distributions by MHD Instabilities II

Description: The modification of particle distributions by low amplitude magnetohydrodynamic modes is an important topic for magnetically confined plasmas. Low amplitude modes are known to be capable of producing significant modification of injected neutral beam profiles, and the same can be expected in burning plasmas for the alpha particle distributions. Flattening of a distribution in an island due to phase mixing and portions of phase space becoming stochastic lead to modification of the particle distribution, a process extremely rapid in the time scale of an experiment but still very long compared to the time scale of guiding center simulations. Large amplitude modes can cause profile avalanche and particle loss. Thus it is very valuable to be able to predict the temporal evolution of a particle distribution produced by a given spectrum of magnetohydrodynamic modes. In this paper we further develop and investigate the use of a new method of determining domains of phase space in which good KAM surfaces do not exist and use this method to examine a well documented case of profile modification by instabilities.
Date: March 2, 2011
Creator: White, Roscoe B.
Partner: UNT Libraries Government Documents Department

Effects of the Noncommutative Standard Model in WW Scattering

Description: We examine W pair production in the Noncommutative Standard Model constructed with the Seiberg-Witten map. Consideration of partial wave unitarity in the reactions WW {yields} WW and e{sup +}e{sup -} {yields} WW shows that the latter process is more sensitive and that tree-level unitarity is violated when scattering energies are of order a TeV and the noncommutative scale is below about a TeV. We find that WW production at the LHC is not sensitive to scales above the unitarity bounds. WW production in e{sup +}e{sup -} annihilation, however, provides a good probe of such effects with noncommutative scales below 300-400 GeV being excluded at LEP-II, and the ILC being sensitive to scales up to 10-20 TeV. In addition, we find that the ability to measure the helicity states of the final state W bosons at the ILC provides a diagnostic tool to determine and disentangle the different possible noncommutative contributions.
Date: December 2, 2008
Creator: Conley, John A. & Hewett, JoAnne L.
Partner: UNT Libraries Government Documents Department

Enhanced K(L) ---> Pi0 Nu Anti-Nu From Direct CP Violation in B ---> K Pi With Four Generations

Description: Recent CP violation results in B decays suggest that Z penguins may have large weak phase. This can be realized by the four generation (standard) model. Concurrently, B {yields} X{sub s}{ell}{sup +}{ell}{sup -} and B{sub s} mixing allow for sizable V*{sub t's}V{sub t'b} only if it is nearly imaginary. Such large effects in b {leftrightarrow} s transitions would affect s {leftrightarrow} d transitions, as kaon constraints would demand V{sub t'd} {ne} 0. Using {Lambda}(Z {yields} b{bar b}) to bound |V{sub t'b}|, they infer sizable |V{sub t's}| {le} |V{sub t'b}| {le} |V{sub us}|. Imposing {var_epsilon}{sub K}, K{sup +} {yields} {pi}{sup +}{nu}{bar {nu}} and {var_epsilon}'/{var_epsilon} constraints, they find V*{sub t'd} V{sub t's} {approx} few x 10{sup -4} with large phase, enhancing K{sub L} {yields} {pi}{sup 0} {nu}{bar {nu}} to 5 x 10{sup -10} or even higher. Interestingly, {Delta}m{sub B{sub d}} and sin 2{Phi}{sub B{sub d}} are not much affected, as |V*{sub t'd} V{sub t'b} << |V*{sub td} V{sub tb}| {approx} 0.01.
Date: September 2, 2005
Creator: Hou, Wei-Shu; /Taiwan, Natl. Taiwan U. /SLAC; Nagashima, Makiko; /Taiwan, Natl. Taiwan U.; Soddu, Andrea & /Taiwan, Natl. Taiwan U. /Weizmann Inst.
Partner: UNT Libraries Government Documents Department

229Th the Bridge Between Nuclear and Atomic Interactions

Description: The precise measurement of time has been a goal of physicists for centuries. With every new increase in our ability to measure time we have discovered new phenomena. The most advanced clocks available to us currently are atomic clocks that use electronic transitions to track the passage of time. In this proposal, I put forward the framework for the first nuclear clock estimated to be 1000 to 10000 times more precise than the current atomic clocks. This research will explore in detail the atomic nuclear interactions and help perfect and refine current atomic-nuclear interaction models. The realization of a {sup 229}Th nuclear clock will allow tests of cosmology by measuring the change of the fine structure constant as a function of time. The results of these experiments could dramatically alter our view of the universe, its past and future evolution. Precision clocks - with fundamental physics applications - require a long-lived quantum transition (two-level system) that is immune to external perturbations. Nuclear transitions would be better suited than atomic transitions for these applications except that nuclear transitions are typically much higher in energy and therefore cannot be accessed with table-top lasers. There is, however, one promising nuclear transition: the doublet between the ground and first excited states of the {sup 229}Th nucleus discovered by Helmer and Reich. This doublet has an energy splitting of 7.6 {+-} 0.5 eV, a spin difference of 1 h-bar, and an excited state half-life that could be as long as hours. A precision clock based on the {sup 229}Th nuclear doublet has been proposed by Peik et al. Their design is similar to the ion clock research being conducted at NIST in Boulder, CO. However, the NIST researchers use atomic transitions for their frequency standards. In the {sup 229}Th nuclear doublet transition is the frequency ...
Date: December 2, 2010
Creator: Burke, J T; Casperson, R J; Swanberg, E L & Thomas, D
Partner: UNT Libraries Government Documents Department

The next generation of photo-detector for particle astrophysics.

Description: We advocate support of research aimed at developing alternatives to the photomultiplier tube for photon detection in large astroparticle experiments such as gamma-ray and neutrino astronomy, and direct dark matter detectors. Specifically, we discuss the development of large area photocathode microchannel plate photomultipliers and silicon photomultipliers. Both technologies have the potential to exhibit improved photon detection efficiency compared to existing glass vacuum photomultiplier tubes.
Date: June 2, 2009
Creator: Wagner, R. G.; Byrum, K. L.; Sanchez, M.; Vaniachine, A. V.; Siegmund, O.; Otte, N.A. et al.
Partner: UNT Libraries Government Documents Department

DE-FG02-04ER84058 Final Report

Description: The goal of the Phase I research was to demonstrate the feasibility of developing a high performance SPECT/CT detector module based on a combination of microcolumnar CsI(Tl) scintillator coupled to an EMCCD readout. We are very pleased to report that our Phase I research has demonstrated the technical feasibility of our approach with a very high degree of success. Specifically, we were able to implement a back-thinned EMCCD with a fiberoptic window which was successfully used to demonstrate the feasibility of near simultaneous radionuclide/CT using the proposed concept. Although significantly limited in imaging area (24 x 24 mm{sup 2}) and pixel resolution (512 x 512), this prototype has shown exceptional capabilities such as a single optical photon sensitivity, very low noise, an intrinsic resolution of 64 {micro}m for radionuclide imaging, and a resolution in excess of 10 lp/mm for x-ray imaging. Furthermore, the combination of newly developed, thick, microcolumnar CsI and an EMCCD has shown to be capable of operating in a photon counting mode, and that the position and energy information obtained from these data can be used to improve resolution in radionuclide imaging. Finally, the prototype system has successfully been employed for near simultaneous SPECT/CT imaging using both, {sup 125}I and {sup 99m}Tc radioisotopes. The tomographic reconstruction data obtained using a mouse heart phantom and other phantoms clearly demonstrate the feasibility and efficacy of the detector in small animal research. The following were the objectives specified in the Phase I proposal: (1) In consultation with Professor Hasegawa, develop specifications for the Phase I/Phase II prototype detector; (2) Modify current vapor deposition protocols to fabricate {approx}2 mm thick microcolumnar CsI(Tl) scintillators with excellent columnar structure, high light yield, and high spatial resolution; (3) Perform detailed characterization of the film morphology, light output, and spatial resolution, and use these data ...
Date: March 2, 2006
Creator: Nagarkar, Vivek
Partner: UNT Libraries Government Documents Department

A Hard X-ray View on Two Distant VHE Blazars: 1ES 1101-232 and 1ES 1553+113

Description: TeV-blazars are known as prominent non-thermal emitters across the entire electromagnetic spectrum with their photon power peaking in the X-ray and TeV-band. If distant, absorption of -ray photons by the extragalactic background light (EBL) alters the intrinsic TeV spectral shape, thereby affecting the overall interpretation. Suzaku observations for two of the more distant TeV-blazars known to date, 1ES 1101-232 and 1ES 1553+113, were carried out in May and July 2006, respectively, including a quasi-simultaneous coverage with the state of the art Cherenkov telescope facilities. We report on the resulting data sets with emphasis on the X-ray band, and set into context to their historical behavior. During our campaign, we did not detect any significant X-ray or {gamma}-ray variability. 1ES 1101-232 was found in a quiescent state with the lowest X-ray flux ever measured. The combined XIS and HXD PIN data for 1ES 1101-232 and 1ES 1553+113 clearly indicate spectral curvature up to the highest hard X-ray data point ({approx} 30 keV), manifesting as softening with increasing energy. We describe this spectral shape by either a broken power law or a log-parabolic fit with equal statistical goodness of fits. The combined 1ES 1553+113 very high energy spectrum (90-500 GeV) did not show any significant changes with respect to earlier observations. The resulting contemporaneous broadband spectral energy distributions of both TeV-blazars are discussed in view of implications for intrinsic blazar parameter values, taking into account the {gamma}-ray absorption in the EBL.
Date: May 2, 2008
Creator: Reimer, A.; Costamente, L.; /Stanford U., HEPL /KIPAC, Menlo Park; Madejski, G.; /KIPAC, Menlo Park /SLAC; Reimer, O. et al.
Partner: UNT Libraries Government Documents Department

Measuring Gamma With B0 to D0 K*0 Decays at Babar

Description: We present a feasibility study for a new analysis for extracting the angle of the Unitarity Triangle from the study of the neutral B meson decays. We reconstruct the decay channel B{sup 0} {yields} {bar D}{sup 0}K*{sup 0} with the K*{sup 0} {yields} K{sup +}{pi}{sup -} and the {bar D}{sup 0} {yields} K{sub S}{pi}{sup +}{pi}{sup -} using a D{sup 0} Dalitz analysis technique. The sensitivity to the angle comes from the interference of the b {yields} c and b {yields} u processes contributing to the same final state and by the fact that the B{sup 0}({bar B}{sup 0}) can be unambiguously identified through the sign of electric charge of the kaon from K*{sup 0}({bar K}*{sup 0}) decay. The impact of the result of such analysis is evaluated for the actual BaBar statistics.
Date: May 2, 2007
Creator: Pruvot, S.; Schune, M.H.; /Orsay, LAL; Sordini, V.; /Orsay, LAL /Rome U. /INFN, Rome; Stocchi, A. et al.
Partner: UNT Libraries Government Documents Department

Errors Associated with the Direct Measurement of Radionuclides in Wounds

Description: Work in radiation areas can occasionally result in accidental wounds containing radioactive materials. When a wound is incurred within a radiological area, the presence of radioactivity in the wound needs to be confirmed to determine if additional remedial action needs to be taken. Commonly used radiation area monitoring equipment is poorly suited for measurement of radioactive material buried within the tissue of the wound. The Lawrence Livermore National Laboratory (LLNL) In Vivo Measurement Facility has constructed a portable wound counter that provides sufficient detection of radioactivity in wounds as shown in Fig. 1. The LLNL wound measurement system is specifically designed to measure low energy photons that are emitted from uranium and transuranium radionuclides. The portable wound counting system uses a 2.5cm diameter by 1mm thick NaI(Tl) detector. The detector is connected to a Canberra NaI InSpector{trademark}. The InSpector interfaces with an IBM ThinkPad laptop computer, which operates under Genie 2000 software. The wound counting system is maintained and used at the LLNL In Vivo Measurement Facility. The hardware is designed to be portable and is occasionally deployed to respond to the LLNL Health Services facility or local hospitals for examination of personnel that may have radioactive materials within a wound. The typical detection levels in using the LLNL portable wound counter in a low background area is 0.4 nCi to 0.6 nCi assuming a near zero mass source. This paper documents the systematic errors associated with in vivo measurement of radioactive materials buried within wounds using the LLNL portable wound measurement system. These errors are divided into two basic categories, calibration errors and in vivo wound measurement errors. Within these categories, there are errors associated with particle self-absorption of photons, overlying tissue thickness, source distribution within the wound, and count errors. These errors have been examined and can cause ...
Date: March 2, 2006
Creator: Hickman, D. P.
Partner: UNT Libraries Government Documents Department