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We report on a preanalytical issue we encountered during routine clinical chemistry analyses, potentially leading to deviated analysis results and believe that it might help other laboratories to overcome similar problems. In a heparin-gel tube we measured an implausible glucose value of 0.06 mmol/L. Re-measurement of the same sample resulted in a glucose value of 5.4 mmol/L. After excluding an analytical error, we inspected the sample closer and found a white material as well as fatty droplets floating on the surface of the plasma tube. Evaluation of these structures revealed that the white particulate matter (WPM) consisted of fibrinogen, platelets and leukocytes and the fatty droplets most probably originated from the separator gel. We concluded that these structures formed a temporary clot in the instruments pipetting needle thereby altering the sampling volume and subsequently the measured glucose value. The formation of WPM might be attributable to high speed centrifugation, high cholesterol levels, the gel formulation or a combination of several issues such as temperature, heparin concentration, pH and patient-specific factors. The gel droplets were most probably caused by an aberrant gel formulation in combination with an improper storage of the empty tubes on the wards prior to phlebotomy. After adding an additional instrument cleansing cycle and changing to another batch of heparin tubes the problems could be significantly reduced.

Introduction Practical and ethical challenges as well as time and costs have restricted the generation of pediatric reference intervals. Therefore, pediatric reference intervals on coagulation parameters based on solid evidence are still scarce. Furthermore, reference intervals by age-group cannot reflect the dynamics of age and sex specific coagulation values during childhood. This study is the first to close this gap and provide continuous age and sex dependent reference intervals during childhood in hemostasis. Methods We used an innovative indirect method for providing continuous reference intervals for five common coagulation parameters: Activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin clotting time (TT), fibrinogen (FIB) and antithrombin (AT). Calculations were performed using retrospective laboratory data from pediatric patients between 2005 and 2015 of two major Austrian hospitals, resulting in a total of 195.360 measurements (aPTT: 55,100; PT: 35,492; TT: 35,295; FIB: 49,789; AT: 19,684). Results This multicenter study provides calculations of continuous reference intervals for five common coagulation parameters in a large pediatric cohort, accounting for age and gender. Conclusion To the best of our knowledge, this is the first multicenter study, determining continuous pediatric coagulation reference intervals based on a large retrospective dataset.

Background: Hemolytic specimens are among the most challenging preanalytical issues in laboratory diagnostics. The type of blood collection tube in use is claimed to influence in vitro hemolysis. We aimed to examine this hypothesis and estimate the respective financial impact, evaluating routine blood samples from the past 4 years. Methods: A total of 47,820 hemolysis index (HI) values from five different time intervals (IV1–IV5) were compared against each other, representing the following tubes: IV1-Sarstedt Monovette; IV2-8 mL/16×100 mm Greiner BioOne (GBO) Vacuette; IV3/IV4-5 mL/16×100 mm GBO Vacuette; IV5-4.5 mL/13×75 mm GBO Vacuette. For estimation of the economic impact, material, personnel and analytical costs were calculated. Results: HI mean values in time interval IV2 were significantly higher than in all other intervals, while mean values amongst all other intervals were comparable. The number of moderately and severely hemolyzed samples increased with incrementing vacuum. Overall comparable costs between intervals IV1 and IV5 were €11,370, €14,045, €12,710, €11,213 and €8138 per 10,000 samples, respectively. Conclusions: Aspiration tubes and low vacuum tubes show comparable hemolysis rates. Increasing vacuum levels are associated with higher hemolysis rates. By decreasing in vitro hemolysis, financial savings up to €5907 per 10,000 samples could be gained.

PURPOSE Hereditary hyperferritinemia cataract syndrome (HHCS) is a rare autosomal dominant hereditary disease, characterized by hyperferritinemia but with absence of body iron excess and early onset of bilateral cataracts. Although 5- to 20-fold increased serum ferritin concentrations have been reported in HHCS patients, data of ferritin levels in aqueous humor have not been obtained. We therefore aimed to investigate the ferritin levels in aqueous humor and serum and further present histological and ultrastructural data of the lens. METHODS During cataract extraction and intraocular lens implantation, aqueous humor and lens aspirate of a 37-year-old HHCS patient were obtained from both eyes. Ferritin levels in serum and aqueous humor were quantitatively analyzed via immunoassays in the HHCS patient and healthy control subjects (n = 6). Lens aspirate in HHCS was analyzed histologically and at the ultrastructural level. Further, genetic mutation screening by polymerase chain reaction and DNA sequencing in blood was performed. RESULTS Serum ferritin levels in the control group were 142.2 ± 38.7 μg/L, whereas in the HHCS patient, this parameter was excessively increased (1086 μg/L). Analysis of ferritin in aqueous humor revealed 6.4 ± 3.8 μg/L in normal control subjects and 146.3 μg/L (OD) and 160.4 μg/L (OS) in the HHCS patient. DNA analysis detected a C>A mutation on position +18, a T>G mutation on position +22, a T>C mutation on position +24, and a T>G polymorphism on position +26 in the iron-responsive element of the light-chain ferritin (L-ferritin) gene. CONCLUSIONS In the HHCS patient, a 23-fold (OD) to 25-fold (OS) increased aqueous humor ferritin level was detected. Therefore, the formation of bilateral cataract in HHCS is most likely a result of elevated aqueous humor ferritin. In addition, a novel mutation in this rare disease in the iron-responsive element of L-ferritin gene is reported.

Introduction: Although centrifugation is performed in almost every blood sample, recommendations on duration and g-force are heterogeneo-us and mostly based on expert opinions. In order to unify this step in a fully automated laboratory, we aimed to evaluate different centrifugation settings and their influence on the results of routine clinical chemistry analytes. Materials and methods: We collected blood from 41 healthy volunteers into BD Vacutainer PST II-heparin-gel- (LiHepGel), BD Vacutainer SST II-serum-, and BD Vacutainer Barricor heparin-tubes with a mechanical separator (LiHepBar). Tubes were centrifuged at 2000xg for 10 minutes and 3000xg for 7 and 5 minutes, respectively. Subsequently 60 and 21 clinical chemistry analytes were measured in plasma and serum samples, respec-tively, using a Roche COBAS instrument. Results: High sensitive Troponin T, pregnancy-associated plasma protein A, ß human chorionic gonadotropin and rheumatoid factor had to be excluded from statistical evaluation as many of the respective results were below the measuring range. Except of free haemoglobin (fHb) measure-ments, no analyte result was altered by the use of shorter centrifugation times at higher g-forces. Comparing LiHepBar to LiHepGel tubes at different centrifugation setting, we found higher lactate-dehydrogenase (LD) (P = 0.003 to < 0.001) and lower bicarbonate values (P = 0.049 to 0.008) in the lat ter. Conclusions: Serum and heparin samples may be centrifuged at higher speed (3000xg) for a shorter amount of time (5 minutes) without alteration of the analytes tested in this study. When using LiHepBar tubes for blood collection, a separate LD reference value might be needed.

Background Inappropriate utilization of laboratory resources is an increasing concern especially in high-throughput facilities. Until now, no reliable information has been published addressing to which extent laboratory results are actually used for clinical decision-making. Therefore, we aimed to close this gap using a novel retrospective approach including a survey of clinicians and nurses. Methods We retrospectively evaluated the number of re-orders for potassium (K), lactate dehydrogenase (LD), aspartate-aminotransferase (AST), activated partial thromboplastin-time (APTT) and prothrombin-time/INR (PT/INR), after the initial order had to be cancelled due to preanalytical non-conformities. We analyzed subgroups regarding time to re-order, ward and sample priority (urgent vs. routine). Subsequently, we surveyed clinicians and nurses, asking for their estimate of the amount of failed re-orders as well as for possible reasons. Results From initially cancelled tests, only ~20% of K, LD, AST and ~30% of APTT and PT/INR tests were re-ordered within 24 h. 70% of the investigated clinical chemistry and 60% of coagulation tests were re-ordered one week after cancellation or not at all. Survey participants quite accurately estimated these numbers. Routine laboratory panels, short stay of out-patients, obsolete test results and avoiding additional phlebotomies were the main reasons for not re-ordering cancelled tests. Conclusions Overall, 60–70% of test results in the investigated assays ordered in a high throughput laboratory are potentially inappropriate or of doubtful clinically importance. Although clinicians and nurses are aware of this situation, it is the duty of laboratory specialists to overcome overutilization in close collaboration with all involved healthcare workers.

Background: Blood collection through intravenous (IV) catheters is a common practice at emergency departments (EDs). This technique is associated with higher in vitro hemolysis rates and may even be amplified by the use of vacuum collection tubes. Our aim was to investigate the association of five different vacuum tubes with hemolysis rates in comparison to an aspiration system under real-life conditions and to propose an equation to estimate the amount of hemolysis, depending on the vacuum collection tube type. Methods: We retrospectively evaluated hemolysis data of plasma samples from our ED, where blood is drawn through IV catheters. Over the past 5 years, we compared 19,001 hemolysis index values amongst each other and against the respective vacuum pressure (Pv) of the collection tubes, which were used within the six observational periods. Results: The highest hemolysis rates were associated with full-draw evacuated tubes. Significantly reduced hemolysis was observed for two kinds of partial-draw tubes. The hemolysis rate of one partial-draw blood collection tube was comparable to those of the aspiration system. Regression analysis of Pv and mean free hemoglobin (fHb) values yielded the formula fHb (g/L)=0.0082*Pv2–0.1143*Pv+ 0.5314 with an R2 of 0.99. Conclusions: If IV catheters are used for blood collection, hemolysis rates directly correlate with the vacuum within the tubes and can be estimated by the proposed formula. By the use of partial-draw vacuum blood collection tubes, hemolysis rates in IV catheter collections can be reduced to levels comparable with collections performed by aspiration systems.

Background: Hemolytic samples are one of the most challenging preanalytical issues in laboratory medicine. Even causes leading to hemolytic specimen are various, including phlebotomy practices. Respective educational interventions as well as the reduction of the number of people involved in blood collections are claimed to influence the sample quality for the better. In our hospital 70 junior doctors were in charge of routine phlebotomy until 2012, when this task was shifted to 874 nurses, including a preceding training in phlebotomy and preanalytics. Our aim was to evaluate the impact of this training effect and the increase of people involved on sample quality. Methods: The hemolysis index (HI) of 43,875 samples was measured before (n=21,512) and after (n=22,363) the switch of blood collection responsibilities. Differences in overall hemolysis rates and the amount of plasma samples with a concentration of free hemoglobin (fHb) above 0.5 g/L and 1 g/L were calculated. Results: Overall HI as well as the percentage of samples with an fHb concentration >0.5 g/L decreased after the responsibility for phlebotomy changed. The rate of samples with an fHb concentration >1 g/L remained unchanged. Conclusions: Hemolysis rates were reduced upon passing phlebotomy tasks from untrained physicians on to a trained nursing staff. We therefore conclude that the number of people performing phlebotomy seems to play a minor role, compared to the effect of a standardized training. However, whether a reduction in the number of people involved in blood collection could lead to further improvement of sample quality, remains to be investigated in future studies.

At 150 kV-pulsed neutron generator at the Fast Neutron Researh Facility is being upgraded to produce a 280-kV-pulsed-He beam for Time-of-Flight Rutherford Backscattering Spectrometry (TOF RBS). Modification are being done by replacing the existing beamline elements by a 400-kV accelerating tube, 45o-double focusing dipole magnet and quadrupole lens. The beam transport system has to be redesigned based on the new elements. The important part of a good pulsed beam depends on the pulsing system. The two main parts are the chopper and buncher. Radiofrequency (RF) of 2 MHz is used for the chopper and 4 MHz for the buncher. For the buncher the RF amplitude of 13 kV is applied to two gaps, so that the ion pulse is compressed twice. An optimized geometry for the 280-keV pulsed helium ion beam is presented in this paper,. The PARMELA code has been used to optimize the space-charge effect, resulting in a excitated pulse width of less than 2 ns at a target. The calculated distance from a buncher to the target is 4.6 m. Effects of energy spread and phase angle between the chopper and buncher have been included in the optimization of the bunch lengh.

Sub-picosecond electron pulses become a tool of increasing importance to study dynamics at an atomic level. Such electron pulses can be used directly or be converted into intense coherent far infrared radiation or equally short X-ray pulses. In principle, sub-picosecond electron pulses can be obtained in large, high-energy electron linear accelerator systems by repeatedly applying an energy slew and magnetic compression. Another process is the production of short electron pulses at low energies from an RF-gun with a thermionic cathode together with a bunch compressing α -magnet. In this paper, we present a systematic analysis of capabilities and limits of sub-picosecond electron pulses from such a source. We discuss particular parameter choices as well as the impact of geometric and electric specifications on the 6-dimensional phase space electron distribution. Numerical beam simulations with the computer code PARMELA are performed including effects and limitations due to space charge forces. While the production of femtosecond electron bunches is of primary concern, we also consider the preservation of such short bunches along a beam transport line.

In previous chapters we have concentrated the discussion on the interaction of transverse electrical and magnetic fields with charged particles and have derived appropriate formalisms to apply this interaction to the design of beam transport systems. The characteristics of these transverse fields is that they allow to guide charged particles along a prescribed path but do not contribute directly to the energy of the particles through acceleration. For particle acceleration we must generate fields with nonvanishing force components in the direction of the desired acceleration.

After Schott’s [3] unsuccessful attempt to explain atomic radiation with his electromagnetic theory no further progress was made for some 40 years mainly because of lack of interest. Only in the mid forties did the theory of electromagnetic radiation from free electrons become interesting again with the successful development of circular high-energy electron accelerators. At this time powerful betatrons [8] have been put into operation and it was Ivanenko and Pomeranchouk [9], who first in 1944 pointed out a possible limit to the betatron principle and maximum energy due to energy loss from emission of electromagnetic radiation. This prediction was used by Blewett [10] to calculate the radiation energy loss per turn in a newly constructed 100 MeV betatron at General Electric. In 1946 he measured the shrinkage of the orbit due to radiation losses and the results agreed with predictions. On April 24, 1947 visible radiation was observed for the first time at the 70 MeV synchrotron built at General Electric [11, 12, 13]. Since then, this radiation is called synchrotron radiation.

The proper operation of the rf-system in a particle accelerator depends more than any other component on the detailed interaction with the particle beam. This results from the observation that a particle beam can induce fields in the accelerating cavities of significant magnitude compared to the generator produced voltages and we may therefore not neglect the presence of the particle beam.

Coupling between horizontal and vertical betatron oscillations plays an important role in beam dynamics. Since coupling is caused by linear as well as nonlinear fields, we observe the effects on beam characteristics in virtually any accelerator. In order to be able to introduce or eliminate coupling, whichever may be the case, in a controlled and predictable way, we need to understand the dynamics of coupling in more detail. In this chapter we will derive first the equations of motion for the two most general sources of coupling, the solenoid field and the field of a rotated quadrupole, solve the equations of motion and formulate modifications to beam dynamics parameters and functions of linear uncoupled motion.

The development of charged particle accelerators and it’s underlying principles has its basis on the theoretical and experimental progress in fundamental physical phenomena. While active particle accelerator experimentation started seriously only in the twentieth century, it depended on the basic physical understanding of electromagnetic phenomena as investigated both theoretically and experimentally mainly during the nineteenth and beginning twentieth century. In this introduction we will recall briefly the history leading to particle accelerator development, applications and introduce basic definitions and formulas governing particle beam dynamics.

Based on d’Alembert’s principle, we formulate Hamilton’s integral principle by defining a function \(L = L(q_{i},\dot{q}_{i},t)\) such that for any mechanical system the variation of the integral \(\int _{t_{0}}^{t_{1}}L\) dt vanishes along any real path (Fig. 4.1) so that $$\displaystyle{ \delta \int _{t_{0}}^{t_{1} }L(t)\text{d}t = 0. }$$ (4.1)

The study of beam dynamics under ideal conditions is the first basic step toward the design of a beam transport system. In the previous sections we have followed this path and have allowed only the particle energy to deviate from its ideal value. In a real particle beam line or accelerator we may, however, not assume ideal and linear conditions. More sophisticated beam transport systems require the incorporation of nonlinear sextupole fields to correct for chromatic aberrations. Deviations from the desired field configurations can be caused by transverse or longitudinal misplacements of magnets with respect to the ideal beam path. Of similar concern are errors in the magnetic field strength, undesirable field effects caused in the field configurations at magnet ends, or higher order multipole fields resulting from design, construction, and assembly tolerances. Still other sources of errors may be beam-beam perturbations, insertion devices in beam transport systems or accelerating sections which are not part of the magnetic lattice configurations. Such systems may be magnetic detectors for high energy physics experiments, wiggler and undulator magnets for the production of synchrotron radiation, a gas jet or immaterial field sources like that of a free electron laser interacting with the particle beam to name just a few examples. The impact of such errors is magnified in strong focusing beam transport systems as has been recognized soon after the invention of the strong focusing principle. Early overviews and references can be found for example in [7.1– 12].

The wide variety of particle beam applications require often very specific beam characteristics in terms of say cross section, divergence, energy spread or pulse structure. To a large extend such parameters can be adjusted by particular application of focusing and other forces. In this chapter, we will discuss some of these methods of beam optimization and manipulation.

The most obvious components of particle accelerators and beam transport systems are those that provide the beam guidance and focusing system. Whatever the application may be, a beam of charged particles is expected by design to follow closely a prescribed path along a desired beam transport line or along a closed orbit in case of circular accelerators. The forces required to bend and direct the charged particle beam or provide focusing to hold particles close to the ideal path are known as the Lorentz forces and are derived from electric and magnetic fields through the Lorentz equation.

While discussing self fields of a charged particle bunch, we noticed a significant effect from nearby metallic surfaces. The dynamics of individual particles as well as collective dynamics of the whole bunch depends greatly on the electromagnetic interaction with the environment. Such interactions must be discussed in more detail to establish stability criteria for particle beams.

Background The order of draw is regarded as a preanalytical issue to prevent carryover of additives during blood collection. Our objective was to prove the theory of ethylenediaminetetraacetic acid (EDTA) carryover for a closed vacuum system and the influence of EDTA on concentrations of selected biomarkers. Methods To test the carryover of EDTA, a blood collection with tripotassium EDTA (K3EDTA) and subsequent non-additive tubes was simulated using distilled water as substitute for blood. EDTA concentrations were measured by tandem mass spectrometry. Then we added increasing concentrations of EDTA to heparinized blood and measured routine biomarkers, thereby simulating a carryover of EDTA whole blood and pure EDTA, respectively. Additionally, we tested for EDTA contamination and biomarker alteration in samples collected from 10 healthy volunteers by a syringe with subsequent transfer into sample tubes. Results No EDTA contamination was detected in samples collected subsequent to a K3EDTA tube when adhering to guidelines of blood sampling. Magnesium, calcium, and potassium levels were altered by artificial K3EDTA whole-blood contamination as well as when adding 1 μL pure K3EDTA. Iron values were altered at EDTA concentrations of 4.4 mmol/L. All other parameters remained unaffected. A slight EDTA carryover was observed in syringe collection and subsequent transfer into EDTA and heparin tubes, however, without any biomarker alteration. Conclusions An EDTA carryover during blood collection using a closed vacuum system is highly unlikely. Even if carryover of EDTA whole blood occurs, an absolute volume larger than 10 μL would be necessary to alter test results. However, contamination of samples with preloaded pure K3EDTA solution by severe neglect of current recommendations in blood collection may significantly alter testing results.

A physics experiment for laser-driven, electron acceleration in a structure-loaded vacuum is being carried out at Stanford University. The experiment is to demonstrate the linear dependence of the electron energy gain on the laser field strength. The accelerator structure, made of dielectric, is semi-open, with dimensions a few thousand times the laser wavelength. The electrons traverse the axis of two crossed laser beams to obtain acceleration within a coherence distance. We predict that the demonstration experiment will produce a single-stage, electron energy gain of 300 keV over a 2.5 mm distance. Ultimately, acceleration gradients of 1 GeV m−1 should be possible.

An overview of the research program and recent experimental results from the SUNSHINE (Stanford University short intense electron source) facility will be presented and discussed. This facility consists of an rf-gun and a magnetic bunch compressor followed by a 30 MeV linear accelerator and associated diagnostic instrumentation. The goal of this research activity is to produce sub picosecond electron pulses, study limitations and use those bunches to generate coherent far infrared radiation or for single pass free electron laser development. High intensity electron bunches with a peak current of 298 A at a bunch length of 70 μm rms or 235 fs rms have been produced at a microbunch charge of 0.17 nC while the shortest bunches reached so far last about 100 fs rms at about 10% of maximum intensity. The experimental setup, numerical simulations for bunch compression, sub picosecond bunch length measurements and limitations on achievable short bunches will be discussed.

Coherent, far-infrared undulator radiation from sub-picosecond electron pulses has been observed at the Stanford SUNSHINE facility. Measured intensities exceed theoretical prediction for spontaneous radiation by more than an order of magnitude. The forward-radiated energy from a 16 MeV electron beam travelling in a single pass through an undulator with a strength parameter K = 0.6 grows exponentially and is consistent with predictions of Self-Amplified Spontaneous Emission (SASE) with a gain length of 45.4 cm or 5.9 undulator periods.

Recently, transform limited optical micropulses with lengths of less than 600 fs FWHM have been produced at the Stanford Picosecond Free Electron Laser (FEL) Center. These sub-picosecond FEL optical pulses are important for many types of experiments, especially those investigating fast kinematic processes. In an effort to understand the details of short optical micropulse production, we have made measurements of the electron beam's micropulse structure with sub-picosecond resolution using a newly constructed electron beam diagnostic which uses transition radiation.

An electron source has been developed at the Stanford SUNSHINE facility which can produce electron bunches as short as 50 fs (rms) with (2[minus]4.6)[times]10[sup 8][ital e][sup [minus]] per microbunch. This source consists of a 2.6 MeV rf gun with a thermionic cathode and an alpha magnet for bunch compression. Coherent transition radiation emitted at wavelengths equal to the bunch length and longer is used in a Michelson interferometer to determine the bunch length by optical autocorrelation. The experimental setup and results of bunch length measurements are described.

Beam requirements for 33 keV radiation used in digital subtraction angiography have been established through extended experimentation first at Stanford and later at the National Synchrotron Light Source in Brookhaven. So far research and development of this medical procedure to image coronary blood vessels have been undertaken on large high energy electron storage rings. With progress in this diagnostic procedure, it is interesting to look for an optimum concept for providing a 33 keV radiation source which would fit into the environment of a hospital. A variety of competing effects and technologies to produce 33 keV radiation are available, but none of these processes provides the combination of sufficient photon flux and monochromaticity except for synchrotron radiation from an electron storage ring. The conceptual design of a compact storage ring optimized to fit into a hospital environment and producing sufficient 33 keV radiation for digital subtraction radiography will be discussed.

The Pohang Light Source (PLS) at the Pohang Accelerator Laboratory has been operated first at 2.0 GeV since 1995, and later was upgraded to 2.5 GeV. During this time, 6 insertion devices like undulators and multipole wigglers have been put into operation to produce special photon beams, with a total of 27 beamlines installed and 3 beamlines under construction. Recently, Korea synchrotron user’s community is demanding high beam stability, higher photon energies as well as more straight sections for insertion devices in the PLS. To meet the user requirements, the PLS‐II upgrade program has been launched in January, 2009, incorporating a modified chromatic version of Double Bend Achromat (DBA) to achieve almost twice as many straight sections as the current PLS with a design goal of the relatively low emittance, e, of 5.9 nm⋅rad. In the PLS‐II, the top‐up injection using full energy linac is planned for much higher stable beam as well and thus the production of hard x‐ray undulator radiation of 8 to 13 keV is anticipated to allow for the successful research program namely Protein Crystallography. The PLS‐II machine components of storage ring, linear accelerator and photon beamlines will be partly dismantled and reinstalled in a 6‐months shutdown beginning January, 2011 and then the PLS‐II upgrade be started the initial commissioning with a 100 mA beam current from July in 2011.

Methods to obtain short and ultra-short particle and photon pulses are described. First we discuss bunch length scaling and limits in storage rings. Pulse durations of the order of a few ps can be obtained from linac based sources like free electron lasers. Finally the techniques to produce very short electron pulses reaching rms values of about 40 fs will be described. Such bunches in connection with magnetic fields radiate high intensity photon pulses of equal time duration at wavelengths equal to or longer than the electron bunch length. An experiment, presently under construction at Stanford, to produce such ultra-short photon pulses with an expected flux of 4×1021 photons/s/100%BW for wave numbers from 1 to about 1000 cm−1 in a train of bunches separated by 350 ps is described. The photon flux in a single micro-bunch of 100 fs (FWHM) duration is expected to be 1016 photons/100%BW.

The design and implementation of a low emittance lattice for the SPEAR storage ring including measurements of the performance of the lattice are presented [J. Safranek, Ph.D. thesis, Stanford University, 1991]. The low emittance lattice is designed to optimize the performance of SPEAR as a synchrotron radiation source while keeping SPEAR hardware changes at a minimum. The horizontal emittance of the electron beam in the low emittance lattice is reduced by a factor of 4 from the previous lattice. This reduces the typical horizontal source size and divergence of the photon beams by a factor of 2 each and increases the photon beam brightness. At 3 GeV the horizontal emittance is 129π nm rad, which makes the low emittance lattice the lowest emittance, running synchrotron radiation source in the world in the 1.5 to 4.0 GeV energy range for the emittance scaled to 3 GeV. The measured vertical emittance was reduced to half that typically seen at SPEAR in the past. The brightness of the photon beams was further increased by reducing βy at the insertion devices to 1.1 m and reducing the energy dispersion at the insertion devices by more than a factor of 2 on average. The horizontal dispersion at the rf cavities was reduced by a factor of nearly 4 which gives much less problems with synchrobetatron resonances. The dynamic and physical apertures of the lattice are large, giving long beam lifetimes and easy injection of electrons. The measurements of the linear optics and intensity dependent phenomena gave reasonable agreement with the design. The overall performance of the machine was very good. Injection rates of 10 to 20 mA/min and larger were achieved routinely, and 100 mA total current was stored. Repeated ramping of stored beam from the injection energy of 2.3 GeV to the running energy of 3.0 GeV was achieved with very little beam loss. This low emittance configuration is expected to be the operating configuration for SPEAR starting in January 1992.

Synchrotron light cna be produced from a relativistic particle beam circulating in a storage ring at extremely high intensity and brilliance over a large spectral region reaching from the far infrared regime to hard x-rays. The particles, either electrons or positrons, radiate as they are deflected in the fields of the storage ring bending magnets or of magnets specially optimized for the production of synchrotron light. The synchrotron light being very intense and well collimated in the forward direction has become a major tool in a large variety of research fields in physics, chemistry, material science, biology, and medicine.