Wakefields in coherent synchrotron radiation

When the electron bunches in a storage ring are sufficiently short the electrons act coherently producing radiation several orders of magnitude more intense than normal synchrotron radiation. This is referred to as Coherent Syncrotron Radiation (CSR). Due to the potential of CSR to provide a good source of Terahertz radiation for our users, the Canadian Light Source (CLS) has been researching the production and application of CSR. CSR has been produced at the CLS for many years, and has been used for a number of applications. However, resonances that permeate the spectrum at wavenumber intervals of 0.074 cm$^{-1}$, and are highly stable under changes in the machine setup, have hampered some experiments. Analogous resonances were predicted long ago in an idealized theory. Through experiments and further calculations we elucidate the resonance and wakefield mechanisms in the CLS vacuum chamber. The wakefield is observed directly in the 30–110 GHz range by rf diodes. These results are consistent with observations made by the interferometer in the THz range. Also discussed will be some practical examples of the application of CSR for the study of condensed phase samples using both transmission and Photoacoustic techniques

Far-infrared Beamline At The Canadian Light Source

The far-infrared beamline at the Canadian Light Source is a state of the art user facility, which offers significantly more far-infrared brightness than conventional globar sources. The infrared radiation is collected from a bending magnet through a 55 X 37 mrad$^{2}$ port to a Bruker IFS 125 HR spectrometer, which is equipped with a nine compartment scanning arm, allowing it to achieve spectral resolution better than 0.001 cm$^{-1}$. Currently the beamline can achieve signal to noise ratios up to 8 times that which can be achieved using a traditional thermal source. This talk will provide an overview of the the beamline, and the capabilities available to users, recent and planned improvements including the addition of a Glow Discharge cell and advances in Coherent Synchrotron Radiation. Furthermore, the process of acquiring access to the facility will be covered

Automatic assignment and fitting of spectra with PGOPHER

An open source program for automatically assigning complex, well resolved spectra.</p

First high-resolution infrared spectra of 2–13C-propane:Analyses of the ν26 (B2) c-type and ν9 (A1) b-type bands

International audienc

Synchrotron-based infrared spectroscopy of formic acid: Confirmation of the reassignment of Fermi-coupled 8 μm states

The empirically derived assignment of the strongly interacting 51 and 92 vibrational states of trans-HCOOH has recently been reassigned on the basis of anharmonic frequency calculations, and this, in turn, affects the assignment of many higher energy states. Here, we investigate the high-resolution synchrotron-based torsional spectrum of trans-HCOOH, and find experimental confirmation that the proposed reassignment is indeed correct, i.e., that 92 is in fact lower in energy than 51. This is largely based on examining the intensity ratio of transitions with the same rotational quantum numbers between the 92-91 and 51-91 hot bands, which indicates that the 51 [92] state has ∼31% 92 [51] character. We also examined the torsional spectrum of trans-HCOOD, and find that the intensity ratios are consistent with 92 instead being higher in energy than 61 (which is analogous to 51 in trans-HCOOD), as previously determined from higher energy spectra

CONTINUATION OF THE PURSUIT OF THE FAR-INFRARED SPECTRUM OF NCNCS, AT THE CANADIAN LIGHT SOURCE

Author Institution: Department of Physics, The Ohio State University, Columbus Ohio, 43210-1106, USA; Department of Physics and Centre for Laser, Atomic, and; Molecular Sciences, University of New Brunswick, P.O. Box 4400; Fredericton NB E3B 5A3, Canada; Canadian Light Source Inc., University of Saskatchewan; 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4,CanadaThe molecule cyanogen iso-thiocyanate, NCNCS, has proved to be the most revealing model system for studying the effects of molecular quantum monodromy, S.~C.~Ross~and~J.~Koput, Phys. Chem. Chem. Phys., {\bf 12}, 8158 (2010)}. In two previous measuring campaigns in May 2011 and May 2012 at the Canadian Light Source (CLS) at the University of Saskatchewan we have obtained a rich collection of high-resolution infrared band systems for both S(CN)$_{2}$ and its isomer NCNCS which is our target molecule. We found experimentally that NCNCS is the more stable isomer. Some results for S(CN)$_{2}$ are reported in the adjacent talk in this session. However, the isomerization between S(CN)$_{2}$ and NCNCS and other reaction products make the attainment of a pure sample of NCNCS difficult and time consuming. We have not yet obtained a satisfactory high-resolution recording of the quasi-linear bending mode in the far infrared in the two allotments of beam time so far available to us. Our theoretical preparations for the project include recent refinements of predictions of intensities in the low-lying bending mode band system, which will be shown. The experimental aspects of obtaining an optimal sample of NCNCS in order to observe the rotational resolved spectrum in the CLS campaign scheduled for May 2013, and an initial report of the results, will also be discussed