Recent results of a seismically isolated optical table prototype designed for advanced LIGO

The Horizontal Access Module Seismic Attenuation System (HAM-SAS) is a mechanical device expressly designed to isolate a multipurpose optical table and fit in the tight space of the LIGO HAM Ultra-High-Vacuum chamber. Seismic attenuation in the detectors' sensitivity frequency band is achieved with state of the art passive mechanical attenuators. These devices should provide an attenuation factor of about 70dB above 10Hz at the suspension point of the Advanced LIGO triple pendulum suspension. Automatic control techniques are used to position the optical table and damp rigid body modes. Here, we report the main results obtained from the full scale prototype installed at the MIT LIGO Advanced System Test Interferometer (LASTI) facility. Seismic attenuation performance, control strategies, improvements and limitations are also discussed

New Seismic Attenuation System (SAS) for the Advanced LIGO Configurations (LIGO2)

A new passive seismic attenuation system is being developed to replace the current passive attenuation stacks in LIGO 2, it is expected to drive the seismic contribution to the interferometer noise below any other noise source. The SAS will be effective completely starting at about 5 Hz, well inside the (uncompensated) gravity gradient noise wall

IKNO, a user facility for coherent terahertz and UV synchrotron radiation

IKNO (Innovation and KNOwledge) is a proposal for a multi-user facility based on an electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range, and of broadband incoherent synchrotron radiation ranging from the IR to the VUV. IKNO can be operated in an ultra-stable CSR mode with photon flux in the terahertz frequency region up to nine orders of magnitude higher than in existing thirdgeneration light sources. Simultaneously to the CSR operation, broadband incoherent synchrotron radiation up to VUV frequencies is available at the beamline ports. The main characteristics of the IKNO storage and its performance in terms of CSR and incoherent synchrotron radiation are described in this paper. The proposed location for the infrastructure facility is Sardinia, Italy

A Revolution in Sustainable Development: An Analysis on Carbon Footprint and Total Cost of a Residential Home Built Using Conventional Materials, in Comparison to Hemp Biocomposite Materials

The way we are currently developing our building structures is unsustainable, with a large amount of greenhouse gas (GHGs) emissions being a direct result of the production and implementation of the materials used in our buildings.&nbsp; The purpose of this honors thesis is to better understand the potential and feasibility of hemp biocomposite materials in construction. A case study will be examined, where a house plan will be taken, and utilized in two homes, one being constructed with conventional materials such as lumber, while the other with hemp biocomposites. Because the same house plan is used in both homes, we can objectively quantify the carbon footprint and monetary cost of both dwellings, and directly compare them. This side by side analysis can allow developers, architects, and hemp-based construction material companies to see the difference in cost and carbon footprint associated with switching to hemp biobased materials.&nbsp; Using professional journals, peer reviewed literature, and interviews with hemp companies, a building product analysis was conducted. This section shows the advantages and potential drawbacks of current building materials, and what are the benefits and drawbacks of transitioning towards hemp biocomposites. Through the building analysis and case study, this thesis is an extensive tool that shows the potential of hemp in future residential home construction.&nbsp; &nbsp; The carbon sequestered through hemp biocomposites is nearly double its conventional counterparts, and its higher cost can be justified as its benefits could be argued to outweigh the difference in total cost when it comes to the price of the home.</p

The pulsar synchrotron: coherent radio emission

We propose a simple physical picture for the generation of coherent radio emission in the axisymmetric pulsar magnetosphere that is quite different from the canonical paradigm of radio emission coming from the magnetic polar caps. In this first paper we consider only the axisymmetric case of an aligned rotator. Our picture capitalizes on an important element of the MHD representation of the magnetosphere, namely the separatrix between the corotating closed-line region (the `dead zone') and the open field lines that originate in the polar caps. Along the separatrix flows the return current that corresponds to the main magnetospheric electric current emanating from the polar caps. Across the separatrix, both the toroidal and poloidal components of the magnetic field change discontinuously. The poloidal component discontinuity requires the presence of a significant annular electric current which has up to now been unaccounted for. We estimate the position and thickness of this annular current at the tip of the closed line region, and show that it consists of electrons (positrons) corotating with Lorentz factors on the order of 10^5, emitting incoherent synchrotron radiation that peaks in the hard X-rays. These particles stay in the region of highest annular current close to the equator for a path-length of the order of one meter. We propose that, at wavelengths comparable to that path-length, the particles emit coherent radiation, with radiated power proportional to N^2, where N is the population of particles in the above path-length. We calculate the total radio power in this wavelength regime and its scaling with pulsar period and stellar magnetic field and show that it is consistent with estimates of radio luminosity based on observations.Comment: Monthly Notices Letters, in pres

Simulation of Coherent Synchrotron Radiation Emission from Rotating Relativistic Electron Layers

The electromagnetic radiation of a rotating relativistic electron layers is studied numerically using particle-in-cell simulation. The results of the simulation confirm all relevant scaling properties predicted by theoretical models. These models may turn out to be important for the understanding of the coherent synchrotron radiation (CSR) instability that may occur in systems as diverse as particle accelerators radio pulsars.Comment: 4 pages, 5 figures, one new figure, corrected minor errors, accepted for publication in Physical Review

Alignment procedure for the VIRGO Interferometer: experimental results from the Frascati prototype

A small fixed-mirror Michelson interferometer has been built in Frascati to experimentally study the alignment method that has been suggested for VIRGO. The experimental results fully confirm the adequacy of the method. The minimum angular misalignment that can be detected in the present set-up is 10 nrad/sqrt{Hz}Comment: 10 pages, LaTex2e, 4 figures, 5 tables. Submitted to Phys. Lett.

Electron Sources for Future Lightsources, Summary and Conclusions for the Activities during FLS 2012

This paper summarizes the discussions, presentations, and activity of the Future Light Sources Workshop 2012 (FLS 2012) working group dedicated to Electron Sources. The focus of the working group was to discuss concepts and technologies that might enable much higher peak and average brightness from electron beam sources. Furthermore the working group was asked to consider methods to greatly improve the robustness of operation and lower the costs of providing electrons.Comment: 11 pages, 7 figures, summary paper from working group Future Light Sources 2012 Workshop at Newport News, Virginia, USA (http://www.jlab.org/conferences/FLS2012/