We report on results of an R&D program to develop new, simple and cost effective techniques to build compact sampling calorimeters utilizing tungsten powder and scintillating fibers. Such calorimeter ...detectors are under consideration for experiments at the planned Electron Ion Collider and the future upgrade of the STAR experiment at RHIC (BNL). In the first year of this R&D project we built two prototypes of very compact electromagnetic calorimeters and tested them at FNAL test beam T1018 in January 2012. Details of the construction technique, results of the test run and future plan will be presented.
Compared with photon-based techniques, proton beam radiation therapy (PBT) may improve the therapeutic ratio of radiation therapy (RT) for locally advanced pancreatic cancer (LAPC), but available ...data have been limited to single-institutional experiences. This study examined the toxicity, survival, and disease control rates among patients enrolled in a multi-institutional prospective registry study and treated with PBT for LAPC.
Between March 2013 and November 2019, 19 patients with inoperable disease across 7 institutions underwent PBT with definitive intent for LAPC. Patients received a median radiation dose/fractionation of 54 Gy/30 fractions (range, 50.4-60.0 Gy/19-33 fractions). Most received prior (68.4%) or concurrent (78.9%) chemotherapy. Patients were assessed prospectively for toxicities using National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. Kaplan-Meier analysis was used to analyze overall survival, locoregional recurrence-free survival, time to locoregional recurrence, distant metastasis-free survival, and time to new progression or metastasis for the adenocarcinoma cohort (17 patients).
No patients experienced grade ≥3 acute or chronic treatment-related adverse events. Grade 1 and 2 adverse events occurred in 78.7% and 21.3% of patients, respectively. Median overall survival, locoregional recurrence-free survival, distant metastasis-free survival, and time to new progression or metastasis were 14.6, 11.0, 11.0, and 13.9 months, respectively. Freedom from locoregional recurrence at 2 years was 81.7%. All patients completed treatment with one requiring a RT break for stent placement.
Proton beam RT for LAPC offered excellent tolerability while still maintaining disease control and survival rates comparable with dose-escalated photon-based RT. These findings are consistent with the known physical and dosimetric advantages offered by proton therapy, but the conclusions are limited owing to the patient sample size. Further clinical studies incorporating dose-escalated PBT are warranted to evaluate whether these dosimetric advantages translate into clinically meaningful benefits.
Many authors have reported the increase in vertebral body height after vertebroplasty. However, McKiernan et al demonstrated dynamic mobility in patients who underwent vertebroplasty and concluded ...that any article that claims vertebral height restoration must control for the dynamic mobility of fractured vertebrae. The purpose of this study was to compare prevertebroplasty (supine cross-table with a bolster beneath) with postvertebroplasty vertebral body height to find out whether vertebroplasty itself really increases the vertebral height.
From July 2005 to July 2010, 102 consecutive patients with 132 VCFs underwent vertebroplasty at our institution. The indications for vertebroplasty were severe pain that was not responsive to medical treatment, and MR imaging-confirmed edematous lesions. Prevertebroplasty (supine cross-table with bolster beneath) lateral radiographs were compared with postvertebroplasty radiographs to evaluate the height change in vertebroplasty. Kyphotic angle and anterior vertebral body height were measured.
The patients ranged in age from 62 to 90 years. There were 16 men and 86 women. The difference in the kyphotic angle between supine cross-table with bolster and postvertebroplasty was -0.49 ± 3.59° (range, -9°-16°), which was not statistically significant (P = 0.124). The difference in the anterior vertebral body height between supine cross-table with bolster and postvertebroplasty was 0.84 ± 3.01 mm (range, -7.91-8.81 mm), which was statistically significant (P = .002).
The restoration of vertebral body height in vertebroplasty seems to be mostly due to the dynamic mobility of fractured vertebrae; vertebroplasty itself does not contribute much to the restoration of vertebral height.
The elliptic (v2) and triangular (v3) azimuthal anisotropy coefficients in central 3He + Au, d + Au, and p + Au collisions at $\sqrt{S_{NN}}$ = 200 GeV are measured as a function of transverse ...momentum (PT) at midrapidity (|n| < 0.9) via the azimuthal angular correlation between two particles both at |n| < 0.9 while the v2(PT) values depend on the colliding systems, the v3(PT) values are system independent within the uncertainties, suggesting an influence on eccentricity from subnucleonic fluctuations in these small-sized systems. Furthermore, these results also provide stringent constraints for the hydrodynamic modeling of these systems.
We report the triton (t) production in midrapidity (|y| < 0.5) Au + Au collisions at $\sqrt{s_{NN}} = 7.7-200$ GeV measured by the STAR experiment from the first phase of the beam energy scan at the ...Relativistic Heavy Ion Collider. The nuclear compound yield ratio ($N_t \times N_p / N^2_d$), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity ($dN_{ch}/dη$) and follows a scaling behavior. The $dN_{ch}/dη$ dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3σ and 3.4σ, respectively, giving a combined significance of 4.1σ. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller $p_T$ acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.
We report the triton (t) production in midrapidity (|y| < 0.5) Au + Au collisions at $\sqrt{s_{NN}} = 7.7-200$ GeV measured by the STAR experiment from the first phase of the beam energy scan at the ...Relativistic Heavy Ion Collider. The nuclear compound yield ratio ($N_t \times N_p / N^2_d$), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity ($dN_{ch}/dη$) and follows a scaling behavior. The $dN_{ch}/dη$ dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3σ and 3.4σ, respectively, giving a combined significance of 4.1σ. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller $p_T$ acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.
We report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at sqrts_{NN}=3.0 GeV, measured by the STAR experiment in the kinematic acceptance of ...rapidity (y) and transverse momentum (p_{T}) within -0.5<y<0 and 0.4<p_{T}<2.0 GeV/c. In the most central 0%-5% collisions, a proton cumulant ratio is measured to be C_{4}/C_{2}=-0.85±0.09 (stat)±0.82 (syst), which is 2σ below the Poisson baseline with respect to both the statistical and systematic uncertainties. The hadronic transport UrQMD model reproduces our C_{4}/C_{2} in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in C_{4}/C_{2} is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3 GeV.
We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C5, C6) and factorial cumulants (κ5, κ6) of net-proton and proton distributions, from ...$\sqrt{s_{NN}}$=3-200 GeV Au+Au collisions at RHIC. The net-proton cumulant ratios generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at $\sqrt{s_{NN}}$ = 3 GeV. C6/C2 for 0-40\% centrality collisions is increasingly negative with decreasing $\sqrt{s_{NN}}$, while it is positive for the lowest $\sqrt{s_{NN}}$ studied. These observed negative signs are consistent with QCD calculations (at baryon chemical potential, μB≤ 110 MeV) that include a crossover quark-hadron transition. In addition, for $\sqrt{s_{NN}}$≥ 11.5 GeV, the measured proton κn, within uncertainties, does not support the two-component shape of proton distributions that would be expected from a first-order phase transition. Taken in combination, the hyper-order proton number fluctuations suggest that the structure of QCD matter at high baryon density, μB~750 MeV ($\sqrt{s_{NN}}$ = 3 GeV) is starkly different from those at vanishing μB~20MeV ($\sqrt{s_{NN}}$ = 200 GeV and higher).
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