AC/DC: The FERMI FEL Split and Delay Optical Device for Ultrafast X-ray Science

Free-electron lasers (FELs) are the most advanced class of light-sources, by virtue of their unique capability to lase high-brightness pulses characterized by wavelengths spanning the extreme-ultraviolet, the soft and hard X-ray spectral domains, as well as by temporal lengths lying in the femtosecond (fs) timescale. The next step to push the current standards in ultrafast X-ray science is strongly linked to the possibility of engineering and exploiting time-resolved experiments exclusively for FELs pulses, ideally having different colors tunable at specific electronic resonance of the chemical elements. At the seeded FERMI FEL (Trieste, Italy) this goal is committed to the optical device known as AC/DC, which stands for the auto correlator/delay creator. AC/DC is designed to double the incoming FEL pulse splitting the photon beam by inserting a grazing incidence flat mirror, thus preserving the spectral and temporal properties, and further delaying one of these two pulses in time. It can independently tune the FEL pulses fluence on the two optical paths by means of solid-state filters, too. Here, we present a detailed description about this optical device. Strong emphasis is dedicated to the AC/DC opto-mechanical design and to the laser-based feedback systems implemented to compensate for any mismatch affecting the FEL optical trajectory, ascribable to both mechanical imperfections and paraxial errors rising during a temporal delay scan

A novel approach based on low field nuclear magnetic resonance for the detection of the pathological components of the sputum of cystic fibrosis patients

This contribute deals with the use of LF-NMR for monitoring the clinical conditions of cystic fibrosis patient

A novel approach based on low-field NMR for the detection of the pathological components of sputum in cystic fibrosis patients

Purpose: Development of a reliable, simple method to monitor lung condition in cystic fibrosis (CF) patients. Lung functionality assessment in CF patients is relevant, as most of them still die of respiratory failure. In lung mucus (sputum) of CF patients, components such as proteins, biopolymers, DNA, bacteria, and mucin are pathologically increased. As lung functionality is related to the amount of the pathological components in the sputum, their determination can help clinicians in monitoring lung condition and planning therapy. Methods: Low-field NMR was used to evaluate the variation of the relaxation time (T2m) of the water hydrogens present in CF sputum in relation to the amounts of the pathological components. Low-field NMR was tested in artificial samples (mucin or alginates), then in conditional sputum (saliva from healthy volunteers, added by different amounts of the pathological components), and finally in 12 patients\u2019 sputums, in which T2m was correlated to a commonly used lung monitoring test (i.e., forced expiratory volume in the first second). Results: T2m significantly (P<0.05) differed between samples with and without pathological components and between healthy and CF patients (P<0.05), in which T2m correlated (r\ubc0.87) with FEV1. Conclusions: The presented method can potentially become a valuable lung-monitoring tool in CF patient

Can low field nuclear magnetic resonance be used to monitor lung functionality of cystic fibrosis patients?

The increase of long surviving cystic fibrosis (CF) patients needs great effort for the assessment of lung functionality/inflammation since the majority of them still die of respiratory failure. The commonly used test (forced expiratory volume in the first second (FEV1), evaluation of inflammatory markers such as blood neutrophil counts (BNC) and acute-phase reactants such as C-reactive protein (CRP)) can be complex in their execution (FEV1) or expensive (BNC, CRP). Thus, in consideration of the intense monitoring required in CF patients, more effective, low cost and simple strategies are urgently necessary. As it is well known [1, 2] that the sputum of patients affected by CF or other obstructive pulmonary diseases contain pathological concentrations of proteins, alginates, DNA, bacteria and mucin, it is conceivable that these components can affect the magnetic relaxation of the water hydrogens entrapped in the sputum as it occurs in aqueous polymeric solutions and gels [3]. As the illness severity is connected to the concentration of these components, Low field NMR could represent a profitable tool to evaluate lung functionality/inflammation. Indeed, measuring the average sputum spin-spin relaxation time T2m of both artificial sputum samples (water added by different amounts of the pathological components), and conditional sputum (healthy volunteers saliva, added by different amounts of the pathological components), we found that T2m is greatly affected by the presence of pathological components when their concentration ranges from normal up to pathological concentrations. In addition, we found a good statistical correlation between T2m - FEV1, T2m - CRP and T2m -BNC. Figure 1 shows the decrease of T2m relative to a CF patient in comparison with healthy subjects and patients affected by less severe lung pathological conditions, i.e. asthma and chronic obstructive pulmonary disease (COPD). In conclusion, we can affirm that Low field NMR has the potential to become a valuable, fast and economic monitoring tool for pulmonary diseases in CF patients, as well as in other chronic pulmonary diseases

AC/DC: The FERMI FEL Split and Delay Optical Device for Ultrafast X-ray Science

Free-electron lasers (FELs) are the most advanced class of light-sources, by virtue of their unique capability to lase high-brightness pulses characterized by wavelengths spanning the extreme-ultraviolet, the soft and hard X-ray spectral domains, as well as by temporal lengths lying in the femtosecond (fs) timescale. The next step to push the current standards in ultrafast X-ray science is strongly linked to the possibility of engineering and exploiting time-resolved experiments exclusively for FELs pulses, ideally having different colors tunable at specific electronic resonance of the chemical elements. At the seeded FERMI FEL (Trieste, Italy) this goal is committed to the optical device known as AC/DC, which stands for the auto correlator/delay creator. AC/DC is designed to double the incoming FEL pulse splitting the photon beam by inserting a grazing incidence flat mirror, thus preserving the spectral and temporal properties, and further delaying one of these two pulses in time. It can independently tune the FEL pulses fluence on the two optical paths by means of solid-state filters, too. Here, we present a detailed description about this optical device. Strong emphasis is dedicated to the AC/DC opto-mechanical design and to the laser-based feedback systems implemented to compensate for any mismatch affecting the FEL optical trajectory, ascribable to both mechanical imperfections and paraxial errors rising during a temporal delay scan

Experimental setups for FEL-based four-wave mixing experiments at FERMI

The recent advent of free-electron laser (FEL) sources is driving the scientific community to extend table-top laser research to shorter wavelengths adding elemental selectivity and chemical state specificity. Both a compact setup (mini-TIMER) and a separate instrument (EIS-TIMER) dedicated to four-wave-mixing (FWM) experiments has been designed and constructed, to be operated as a branch of the Elastic and Inelastic Scattering beamline: EIS. The FWM experiments that are planned at EIS-TIMER are based on the transient grating approach, where two crossed FEL pulses create a controlled modulation of the sample excitations while a third time-delayed pulse is used to monitor the dynamics of the excited state. This manuscript describes such experimental facilities, showing the preliminary results of the commissioning of the EIS-TIMER beamline, and discusses original experimental strategies being developed to study the dynamics of matter at the fs-nm time-length scales. In the near future such experimental tools will allow more sophisticated FEL-based FWM applications, that also include the use of multiple and multi-color FEL pulses