Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at {\surd}s = 7 TeV in dedicated runs with the Roman Pot detectors placed as close as ...seven times the transverse beam size (sbeam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of d t = 0.1GeV p|t|. In this letter, first results of the differential cross section are presented covering a |t|-range from 0.36 to 2.5GeV2. The differential cross-section in the range 0.36 < |t| < 0.47 GeV2 is described by an exponential with a slope parameter B = (23.6{\pm}0.5stat {\pm}0.4syst)GeV-2, followed by a significant diffractive minimum at |t| = (0.53{\pm}0.01stat{\pm}0.01syst)GeV2. For |t|-values larger than ~ 1.5GeV2, the cross-section exhibits a power law behaviour with an exponent of -7.8_\pm} 0.3stat{\pm}0.1syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.
The U238 to U235 fission cross section ratio has been determined at n_TOF up to ˜1 GeV, with two different detection systems, in different geometrical configurations. A total of four datasets has ...been collected and compared. They are all consistent to each other within the relative systematic uncertainty of 3–4%. The data collected at n_TOF have been suitably combined to yield a unique fission cross section ratio as a function of neutron energy. The result confirms current evaluations up to 200 MeV. Good agreement is also observed with theoretical calculations based on the INCL++/Gemini++ combination up to the highest measured energy. The n_TOF results may help solve a long-standing discrepancy between the two most important experimental datasets available so far above 20 MeV, while extending the neutron energy range for the first time up to ˜1 GeV.
Primitive leptomeningeal melanoma is a rare and aggressive condition. The authors report on a case of primitive leptomeningeal melanoma imaged with 99mTc-Sestamibi (MIBI). There was an intense ...accumulation of the radiotracer in the frontal and parietal leptomeningeal regions and even after injections of gadolinium the MRI continued to reveal a cystic image of the brain. In view of the diagnosis, MRI demonstrated only limited usefulness. On the other hand, this case highlights the important role of MIBI for the imaging of malignant tumors.
The neutron capture cross section of 232Th has been measured relative to σ(n, γ) for 197Au and σ(n,f) for 235U in the energy range from 60 keV to 2 MeV. Neutrons were produced by the 7Li(p,n) and ...T(p,n) reactions at the 4-MV Van de Graaff Accelerator of CEN Bordeaux-Gradignan. The activation technique was used, and the cross section was measured relative to the 197Au(n,γ) standard cross section up to 1 MeV. The characteristic gamma lines of the product nuclei 233Pa and 198Au were measured with a 40% high-purity germanium detector. Above this energy, the reaction 235U(n,f) was also used as a second standard, and the fission fragments were detected with a photovoltaic cell. The results, after applying the appropriate corrections, indicate that the cross sections are close to the JENDL-3 database values up to 800 keV and over 1.4 MeV. For energies in the intermediate range, our values are slightly lower than those from all the libraries. (ANS)
Purpose In vivo confocal microscopy (IVCM) is routinely used in well‐equipped reference centers for the diagnosis of complicated corneal and conjunctival diseases, mainly infectious and tumoral ones. ...At present, only two CM are available for ophthalmology. Both are attached on a classical ophthalmology stand optimized for corneal examination. Aim: to expose new perspectives in examination of cornea, conjunctiva and ocular using a handheld dermatological CM
Methods Using the handheld dermatological reflectance laser‐scanning microscope (Vivascope 3000, MAVIG GmbH) equipped with a 830nm laser, we observed cornea, bulbar and tarsal conjunctiva, eyelid margin, lacrimal puncta and palbebral skin of healthy volunteers as well as none pigmented or pigmented lesions of these sites. Correlations with histopathology were established whenever surgery was necessary
Results Thanks to its compact configuration and flexible, handheld positioning, the Vivascope3000 made it possible to easily access ocular and periocular tissue that remained challenging to observe with ophthalmological CM. With a definition of 1pixel/μm and 1000x1000 μm images, the handheld CM allowed non‐invasive optical biopsy of all normal and pathologic ocular surface as well as periocular tissues. Diagnosis of benign or malignant tumors (melanoma or epidermoid carcinoma) could be highly suspected. Confocal images were well correlated with conventional histopathology
Conclusion The compact handheld Vivascope 3000 offers new perspectives for diagnosis, optimization of treatments, and follow‐up of ocular surface and ocular adnexa diseases
PDF
