Lorentz breaking Effective Field Theory and observational tests

Analogue models of gravity have provided an experimentally realizable test field for our ideas on quantum field theory in curved spacetimes but they have also inspired the investigation of possible departures from exact Lorentz invariance at microscopic scales. In this role they have joined, and sometime anticipated, several quantum gravity models characterized by Lorentz breaking phenomenology. A crucial difference between these speculations and other ones associated to quantum gravity scenarios, is the possibility to carry out observational and experimental tests which have nowadays led to a broad range of constraints on departures from Lorentz invariance. We shall review here the effective field theory approach to Lorentz breaking in the matter sector, present the constraints provided by the available observations and finally discuss the implications of the persisting uncertainty on the composition of the ultra high energy cosmic rays for the constraints on the higher order, analogue gravity inspired, Lorentz violations.Comment: 47 pages, 4 figures. Lecture Notes for the IX SIGRAV School on "Analogue Gravity", Como (Italy), May 2011. V.3. Typo corrected, references adde

Performance of 1-mm^2 silicon photomultiplier

A silicon photomultiplier (SPM) is a large area detector consisting of a parallel array of photon counting microcells. Each microcell consists of a Geiger Mode photodiode with an integrated quenching element. Each microcell is then connected to a common output. The microcells have a uniform gain of up to 10(6) and provide an identical charge output signal for each photon detected. Under illumination the summed output of the detector is proportional to the number of Geiger pulses and hence proportional to the incident photon flux. This combination gives extremely high performance comparable to that of a conventional photomultiplier tube (PMT). We report on the characterization of two different 1 mm(2) SPM detector designs with 620 and 920 microcells at room temperature (20 degrees C) and down to -30 degrees C. We assess detection efficiency, breakdown voltage, gain, dark rate, crosstalk, timing jitter and dynamic range. The SPM detector operates over the visible region of the spectrum, characterized here from 400 to 800 nm. The peak photon detection efficiency of 15 % occurs at 500 nm with a cooled (-20 degrees C) dark rate of 600 kHz/mm(2) at a bias voltage of 31 V. In a test for positron emission tomography (PET), an energy resolution of 25 % was recorded for the detection of 511 keV gamma radiation using 1 mm x 1 mm x 15 mm LYSO scintillator crystal. The SPM has many applications such as medical imaging, microscopy, high-energy physics, and homeland security

CLARA conceptual design report

This report describes the conceptual design of a proposed free electron laser test facility called CLARA that will be a major upgrade to the existing VELA accelerator test facility at Daresbury Laboratory in the UK. CLARA will be able to test a number of new free electron laser schemes that have been proposed but require a proof of principle experiment to confirm that they perform as predicted. The primary focus of CLARA will be on ultra short photon pulse generation which will take free electron lasers into a whole new regime, enabling a new area of photon science to emerge

Synthesis and Biological Evaluation of PSMA Ligands with Aromatic Residues and Fluorescent Conjugates Based on Them

Prostate-specific membrane antigen (PSMA), also known as glutamate carboxypeptidase II (GCPII), is a suitable target for specific delivery of antitumor drugs and diagnostic agents due to its overexpression in prostate cancer cells. In the current work, we describe the design, synthesis, and biological evaluation of novel low-molecular PSMA ligands and conjugates with fluorescent dyes FAM-5, SulfoCy5, and SulfoCy7. In vitro evaluation of synthesized PSMA ligands on the activity of PSMA shows that the addition of aromatic amino acids into a linker structure leads to a significant increase in inhibition. The conjugates of the most potent ligand with FAM-5 as well as SulfoCy5 demonstrated high affinities to PSMA-expressing tumor cells in vitro. In vivo biodistribution in 22Rv1 xenografts in Balb/c nude mice of PSMA-SulfoCy5 and PSMA-SulfoCy7 conjugates with a novel PSMA ligand demonstrated good visualization of PSMA-expressing tumors. Also, the conjugate PSMA-SulfoCy7 demonstrated the absence of any explicit toxicity up to 87.9 mg/kg. © 2021 American Chemical Society. All rights reserved