CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Red-emitting liquid and plastic scintillators with nanosecond time response

International audienceDue to the extreme experimental conditions encountered, the Laser Megajoule facility (LMJ) needs to develop and characterize new organic scintillators with unseen features: a fast decay time, in the order of one nanosecond with almost no afterglow, and an emission wavelength in the red region, typically more than 600 nm. Thus, various compositions have been evaluated, prepared and tested. The materials are composed of a matrix (either liquid or plastic) embedding two fluorophores and a light quencher. Time-Correlated Single Photon Counting was used to assess the main criteria of the materials, which is their photoluminescence decay. In the liquid state, ultra-fast materials were successfully prepared. One liquid scintillator formulation showed the following characteristics: an emission wavelength > 600 nm, a mean decay time of 0.84 ns with a FWHM pulse width of 1.92 ns. In the plastic state the preparation was less straightforward. A plastic scintillator with emission wavelength > 600 nm, a decay time < 7 ns with a FWHM of 8.60 ns was obtained. We have verified that the best plastic sample does not present any afterglow. A light yield around 200 ph/MeV has been estimated from relative radioluminescence measurements, this value being around 4 times lower than the BC-422Q 2%, quenched plastic scintillator

Labeling strategy to improve neutron/gamma discrimination with plastic scintillator using artificial neural network

International audienceOrganic scintillators are widely used for neutron/gamma detection. Pulse shape discrimination algorithms have been commonly used to discriminate the detected radiations. These algorithms have several limits, in particular with plastic scintillator which has lower discrimination ability, compared to liquid scintillator. Recently, machine learning (ML) models have been explored to enhance discrimination performance. Nevertheless, obtaining an accurate ML model or evaluating any discrimination approach requires a reference neutron dataset. The preparation of this is challenging because neutron sources are also gamma-ray emitters. Therefore, this paper proposes a pipeline to prepare clean labeled neutron/gamma datasets acquired by an organic scintillator. The method is mainly based on a Time of Flight setup and Tail-to-Total integral ratio ($TTT_{ratio}$) discrimination algorithm. In the presented case, EJ276 plastic scintillator and $^{252}$Cf source were used to implement the acquisition chain. The results showed that this process can identify and remove mislabeled samples in the entire ToF spectrum, including those that contribute to peak values. Furthermore, the process cleans ToF dataset from pile-up events, which can significantly impact experimental results and the conclusions extracted from them

Relationship between vagal tone, cortisol, TNF-alpha, epinephrine and negative affects in Crohn's disease and irritable bowel syndrome.

Crohn's disease (CD) and irritable bowel syndrome (IBS) involve brain-gut dysfunctions where vagus nerve is an important component. The aim of this work was to study the association between vagal tone and markers of stress and inflammation in patients with CD or IBS compared to healthy subjects (controls). The study was performed in 73 subjects (26 controls, 21 CD in remission and 26 IBS patients). The day prior to the experiment, salivary cortisol was measured at 8:00 AM and 10:00 PM. The day of the experiment, subjects completed questionnaires for anxiety (STAI) and depressive symptoms (CES-D). After 30 min of rest, ECG was recorded for heart rate variability (HRV) analysis. Plasma cortisol, epinephrine, norepinephrine, TNF-alpha and IL-6 were measured in blood samples taken at the end of ECG recording. Compared with controls, CD and IBS patients had higher scores of state-anxiety and depressive symptomatology. A subgroup classification based on HRV-normalized high frequency band (HFnu) as a marker of vagal tone, showed that control subjects with high vagal tone had significantly lower evening salivary cortisol levels than subjects with low vagal tone. Such an effect was not observed in CD and IBS patients. Moreover, an inverse association (r =  -0.48; p<0.05) was observed between the vagal tone and TNF-alpha level in CD patients exclusively. In contrast, in IBS patients, vagal tone was inversely correlated with plasma epinephrine (r =  -0.39; p<0.05). No relationship was observed between vagal tone and IL-6, norepinephrine or negative affects (anxiety and depressive symptomatology) in any group. In conclusion, these data argue for an imbalance between the hypothalamus-pituitary-adrenal axis and the vagal tone in CD and IBS patients. Furthermore, they highlight the specific homeostatic link between vagal tone and TNF-alpha in CD and epinephrine in IBS and argue for the relevance of vagus nerve reinforcement interventions in those diseases

Relationship between the resting parasympathetic vagal tone and the evening salivary cortisol in controls, Crohn’s disease (CD) and Irritable bowel syndrome (IBS) patients.

<p>A balance was observed between the parasympathetic tone and the evening salivary cortisol in healthy subjects (control group) but not in CD and IBS patients. Data are expressed as mean ± sem. Comparisons are made between the high and low parasympathetic level subgroups using permutations test.</p

Specific inverse relationship between the resting parasympathetic vagal tone and epinephrine plasma level in IBS patients.

<p>IBS patients with low parasympathetic vagal tone exhibit a higher level of plasma epinephrine at rest than those with high parasympathetic vagal tone. This inverse relationship was not observed in controls or CD patients. Data are expressed as mean ± sem. Comparisons are made between the high and low parasympathetic level subgroups using permutations test.</p

Data representing the sub-group categorization based on HFnu-HRV K-mean classification.

<p>Data are expressed as mean ± sem. Comparisons are made between low and high parasympathetic level using permutations test.</p><p>*p<0.05;</p><p>**p<0.01;</p><p>***p<0.001.</p><p>Data representing the sub-group categorization based on HFnu-HRV K-mean classification.</p

Influence of the vagal tone on the plasma levels of the morning salivary and plasma cortisol, IL-6, norepinephrine concentrations, state-anxiety and depressive symptomatology scores in Controls, Crohn’s disease (CD) and Irritable Bowel syndrome (IBS) patients.

<p>Data are expressed as mean ± sem. Comparisons are made between low and high parasympathetic level using permutations test.</p><p>Influence of the vagal tone on the plasma levels of the morning salivary and plasma cortisol, IL-6, norepinephrine concentrations, state-anxiety and depressive symptomatology scores in Controls, Crohn’s disease (CD) and Irritable Bowel syndrome (IBS) patients.</p