Characterization of PARIS LaBr3_3(Ce)-NaI(Tl) phoswich detectors upto EγE_\gamma ∼\sim 22 MeV

In order to understand the performance of the PARIS (Photon Array for the studies with Radioactive Ion and Stable beams) detector, detailed characterization of two individual phoswich (LaBr$_3$(Ce)-NaI(Tl)) elements has been carried out. The detector response is investigated over a wide range of $E_{\gamma}$ = 0.6 to 22.6 MeV using radioactive sources and employing $^{11}B(p,\gamma)$ reaction at $E_p$ = 163 keV and $E_p$ = 7.2 MeV. The linearity of energy response of the LaBr$_3$(Ce) detector is tested upto 22.6 MeV using three different voltage dividers. The data acquisition system using CAEN digitizers is set up and optimized to get the best energy and time resolution. The energy resolution of $\sim$ 2.1% at $E_\gamma$ = 22.6~MeV is measured for the configuration giving best linearity upto high energy. Time resolution of the phoswich detector is measured with a $^{60}$Co source after implementing CFD algorithm for the digitized pulses and is found to be excellent (FWHM $\sim$ 315~ps). In order to study the effect of count rate on detectors, the centroid position and width of the $E_{\gamma}$ = 835~keV peak were measured upto 220 kHz count rate. The measured efficiency data with radioactive sources are in good agreement with GEANT4 based simulations. The total energy spectrum after the add-back of energy signals in phoswich components is also presented.Comment: Accepted in JINS

The PARIS cluster coupled to the BaFPro electronic module: data analysis from the NRF experiment at the γ\gammaELBE facility

International audience; The first cluster of the constructed PARIS calorimeter was assembled and tested atthe ELBE facility at HZDR, Dresden, Germany. The experiment was aimed at the evaluationof the performance of each detector separately as well as the whole PARIS cluster with discrete$\gamma$-ray energies seen by the PARIS ranging up to 8.9 MeV. As the detectors use phoswichconfiguration, with 2'' x 2'' x 2'' LaBr3(Ce) crystal coupled to 2'' x 2'' x 6'' NaI(Tl) one, greatcare must be taken during the data analysis process to obtain the best possible values for energyresolution. Two algorithms for data transformation from matrices created with slow vs fastpulse shaping to energy spectra were tested from which one was chosen for further analysis. Analgorithm for adding back energies of $\gamma$-rays scattered inside the cluster was prepared, as well.Energy resolution for $\gamma$-rays in 2–8 MeV range was estimated and is presented in this paper

On fixed divisors of the values of the minimal polynomials over Z of algebraic numbers

Let $K$ be a number field of degree $n$, $A$ be its ring of integers, and $A_n$ (resp. $K_n$) be the set of elements of $A$ ( resp. $K$) which are primitive over $\mathbb Q$. For any $\gamma \in {K_n}$, let $F_{\gamma} (x)$ be the unique irreducible polynomial in $\mathbb Z[x]$, such that its leading coefficient is positive and $F_{\gamma} ({\gamma}) = 0$. Let $i(\gamma)=\gcd_{x\in\mathbb Z}F_{\gamma}(x)$, i(K)=\lcm_{\theta\in{A_n}}i(\theta) and \hat{\imath}(K) = \lcm_{\gamma\in{K_n}}i(\gamma). For any $\gamma \in {K_n}$, there exists a unique pair $(\theta,d)$, where $\theta\in A_n$ and $d$ is a positive integer such that $\gamma=\theta/d$ and $\theta\not\equiv 0\pmod{p}$ for any prime divisor $p$ of $d$. In this paper, we study the possible values of $\nu_{p}(d)$ when $p | i(\gamma)$. We introduce and study a new invariant of $K$ defined using $\nu_{p}(d)$, when $\gamma$ describes $K_n$. In the last theorem of this paper, we establish a generalisation of a theorem of MacCluer

ON FIXED DIVISORS OF THE MINIMAL POLYNOMIALS OVER Z OF ALGEBRAIC NUMBERS

International audienceLet K be a number field of degree n, A be its ring of integers, and A n (resp. K n) be the set of elements of A (resp. K) which are primitive over Q. For any γ ∈ K n , let F γ (x) be the unique irreducible polynomial in Z[x], such that its leading coefficient is positive and F γ (γ) = 0. Let i(γ) = gcd x∈Z F γ (x), i(K) = lcm θ ∈A n i(θ) andî(K) = lcm γ∈K n i(γ). For any γ ∈ K n , there exists a unique pair (θ , d), where θ ∈ A n and d is a positive integer such that γ = θ /d and θ ≡ 0 (mod p) for any prime divisor p of d. In this paper, among other results, we show that i(K) andî(K) have the same prime factors and we study the possible values of ν p (d) when p|i(γ). We introduce and study a new invariant of K defined using ν p (d), when γ describes K n. In the last theorem of this paper, we establish a generalisation of a theorem of MacCluer. From Lemma 2.1 we see that any prime factor p of c(γ) divides d(γ). Summarizing the relations between c(γ) and d(γ), we have : Remark 2.1. Let K be a number field of degree n and γ ∈ K n , then d(γ) and c(γ) have the same prime factors and for any prime p, we have ν p (d(γ)) ≤ ν p (c(γ)) ≤ nν p (d(γ))

1H and 13C \NMR\ spectra of condensed benzimidazole and imidazobenzodiazepines

International audienceBenzimidazoles are heterocyclic compounds that have awakened great interest during the last few years because of their proven biological activity as antiviral, antimicrobial, and antitumoral agents. For this reason, the development of a systematic \NMR\ study of condensed benzimidazole compounds constitutes a significant tool in understanding the molecular dynamics and the structural parameters that govern their behavior. The 1H and 13C \NMR\ spectra of new imidazobenzodiazepines were investigated. Based on the study of \NMR\ chemical shifts, we discuss the environmental effect of the nucleus 13C. The correlation 1H-13C proved to be a useful method for distinguishing the assignment of carbon

Etude analytique et numérique de la réponse en vibration à hautes fréquences d'éprouvettes de fatigue vibratoire des métaux. Application aux aciers

In the present paper, the so-called " ultrasonic fatigue " or fatigue at very high frequency has been studied in the materials elastic behaviour case while neglecting the thermal effects that influence the mechanical fields. The determination of mechanical fields and specimen resonance length has been done both analytically and numerically. The numerical method used for this calculation is the finite element method (FEM). Martensitic steel " Soleil A2 " and austenitic steel " ICL 472 BC " have been considered in order to compare the two methods (analytical and numerical). It is shown that a perfect convergence is obtained between the two solutions.Dans le présent travail, la fatigue vibratoire a été étudiée dans le cas du comportement élastique des matériaux en négligeant les effets thermiques pouvant influencer les champs mécaniques. La détermination de ces champs et de la longueur de résonance des éprouvettes de fatigue a été faite analytiquement et numériquement. Le calcul numérique effectué se base sur la méthode des éléments finis. Dans le but d'une comparaison des solutions analytiques et numériques, deux aciers ont été considérés : un acier martensitique (Soleil A2) et un acier austénitique de type 18-10 (ICL 472 BC). Une parfaite convergence est obtenue entre les deux solutions

Condensation of 7-nitroindole-2-carbohydrazide derivatives with ethyl acetoacetate

International audiencePyrazolylindolyl ketone derivatives were obtained by cyclization of the condensation products 7-nitroindole-2-carbohydrazide derivatives with ethyl acetoacetate. We have shown careful examination of spectroscopic data and the open-chain intermediate isolation as well as the identification of the formed compound structure