Elemental depth profiling of thin film chalcogenides using MeV ion beam analysis

The comprehensive characterisation is one of many technical challenges in the fabrication of photovoltaic devices from novel materials. We show how the application of recent advances in MeV ion beam analysis, providing the selfconsistent treatment of Rutherford backscattering and particle induced X-ray emission spectra, makes a new set of powerful complementary elemental depth profiling techniques available for all thin film technologies, including the chalcopyrite compound semiconductors. We will give and discuss a detailed analysis of a CuInAl metallic precursor film, showing how similar methods are also applicable to other films of interest

Towards truly simultaneous PIXE and RBS analysis of layered objects in cultural heritage

For a long time, RBS and PIXE techniques have been used in the field of cultural heritage. Although the complementarity of both techniques has long been acknowledged, its full potential has not been yet developed due to the lack of general purpose software tools for analysing the data from both techniques in a coherent way. In this work we provide an example of how the recent addition of PIXE to the set of techniques supported by the DataFurnace code can significantly change this situation. We present a case in which a non homogeneous sample (an oxidized metal from a photographic plate -heliography- made by Niepce in 1827) is analysed using RBS and PIXE in a straightforward and powerful way that can only be performed with a code that treats both techniques simultaneously as a part of one single and coherent analysis. The optimization capabilities of DataFurnace, allowed us to obtain the composition profiles for these samples in a very simple way.Comment: 9 pages, 3 figure

A Maximum Entropy Resolution to the Wine/Water Paradox.

The Principle of Indifference ('PI': the simplest non-informative prior in Bayesian probability) has been shown to lead to paradoxes since Bertrand (1889). Von Mises (1928) introduced the 'Wine/Water Paradox' as a resonant example of a 'Bertrand paradox', which has been presented as demonstrating that the PI must be rejected. We now resolve these paradoxes using a Maximum Entropy (MaxEnt) treatment of the PI that also includes information provided by Benford's 'Law of Anomalous Numbers' (1938). We show that the PI should be understood to represent a family of informationally identical MaxEnt solutions, each solution being identified with its own explicitly justified boundary condition. In particular, our solution to the Wine/Water Paradox exploits Benford's Law to construct a non-uniform distribution representing the universal constraint of scale invariance, which is a physical consequence of the Second Law of Thermodynamics

Accurate experimental determination of gallium K- and L3-shell XRF fundamental parameters

The fluorescence yield of the K- and L3-shell of gallium was determined using the radiometrically calibrated (reference-free) X-ray fluorescence instrumentation at the BESSY II synchrotron radiation facility. Simultaneous transmission and fluorescence signals from GaSe foils were obtained, resulting in K- and L3-shell fluorescence yield values consistent with existing database values(omega_Ga_K=0.515 +- 0.019, omega_Ga_L3=0.013 +- 0.001). For the first time, these standard combined uncertainties are obtained from a properly constructed Uncertainty Budget. These K-shell fluorescence yield values support Bambynek's semi-empirical compilation from 1972: these and other measurements yield a combined recommended value of omega_Ga_K=0.514 +- 0.010. Using the measured fluorescence yields together with production yields from reference Ga-implanted samples where the quantity of implanted Ga was determined at 1.3% traceable accuracy by Rutherford backscattering spectrometry, the K-shell and L3-subshell photoionization cross sections at selected incident photon energies were also determined and compared critically with the standard databases.Comment: 17 pages, 6 figure

The effect of irradiation-induced disorder on the conductivity and critical temperature of the organic superconductor κ\kappa-(BEDT-TTF)2_2Cu(SCN)2_2

We have introduced defects into clean samples of the organic superconductor $\kappa$-(BEDT-TTF)$_2$Cu(SCN)$_2$ in order to determine their effect on the temperature dependence of the conductivity and the critical temperature $T_{\rm c}$. We find a violation of Matthiessen's rule that can be explained by a model of the conductivity involving a defect-assisted interlayer channel which acts in parallel with the band-like conductivity. We observe an unusual dependence of $T_{\rm c}$ on residual resistivity which is not consistent with the generalised Abrikosov-Gor'kov theory for an order parameter with a single component, providing an important constraint on models of the superconductivity in this material

Clinician perspectives on what constitutes good practice in community services for people with complex emotional needs: A qualitative thematic meta-synthesis

INTRODUCTION: The need to improve the quality of community mental health services for people with Complex Emotional Needs (CEN) (who may have a diagnosis of 'personality disorder') is recognised internationally and has become a renewed policy priority in England. Such improvement requires positive engagement from clinicians across the service system, and their perspectives on achieving good practice need to be understood. AIM: To synthesise qualitative evidence on clinician perspectives on what constitutes good practice, and what helps or prevents it being achieved, in community mental health services for people with CEN. METHODS: Six bibliographic databases were searched for studies published since 2003 and supplementary citation tracking was conducted. Studies that used any recognised qualitative method and reported clinician experiences and perspectives on community-based mental health services for adults with CEN were eligible for this review, including generic and specialist settings. Meta-synthesis was used to generate and synthesise over-arching themes across included studies. RESULTS: Twenty-nine papers were eligible for inclusion, most with samples given a 'personality disorder' diagnosis. Six over-arching themes were identified: 1. The use and misuse of diagnosis; 2. The patient journey into services: nowhere to go; 3. Therapeutic relationships: connection and distance; 4. The nature of treatment: not doing too much or too little; 5. Managing safety issues and crises: being measured and proactive; 6. Clinician and wider service needs: whose needs are they anyway? The overall quality of the evidence was moderate. DISCUSSION: Through summarising the literature on clinician perspectives on good practice for people with CEN, over-arching priorities were identified on which there appears to be substantial consensus. In their focus on needs such as for a long-term perspective on treatment journeys, high quality and consistent therapeutic relationships, and a balanced approach to safety, clinician priorities are mainly congruent with those found in studies on service user views. They also identify clinician needs that should be met for good care to be provided, including for supervision, joint working and organisational support

Bonding structure and hydrogen content in silicon nitride thin films deposited by the electron cyclotron resonance plasma method

The bonding structure and hydrogen content of amorphous hydrogenated silicon nitride (a-SiNx:H) thin films have been investigated by infrared spectroscopy and ion beam techniques. Electron cyclotron resonance plasma enhanced chemical vapor deposition was used to produce these films under different values of gas flow ratio, deposition temperature, and microwave power. The amount of bonded hydrogen was calculated from the N-H and Si-H infrared absorption bands. An increase of the SiH4 partial pressure during deposition was found to have the same effect on the H content as an increase of the substrate temperature: both cause a decrease of the N-H bond density and an increase in the number of Si-H bonds. This is explained by a competitive process in the formation of N-H and Si-H bonds during the growth of the film, whereby Si-H bonds are favored at the expense of N-H bonds when either the SiH4 flow or the substrate temperature are increased. Such tendency to chemical order is compared with previous results in which the same behavior was induced by thermal annealing or ion beam bombardment

How “Berry Phase” Analysis of Non-Adiabatic Non-Hermitian Systems Reflects Their Geometry

There is currently great interest in systems represented by non-Hermitian Hamiltonians, including a wide variety of real systems that may be dissipative and whose behaviour can be represented by a “phase” parameter that characterises the way “exceptional points” (singularities of various sorts) determine the system. These systems are briefly reviewed here with an emphasis on their geometrical thermodynamics properties