Radiation Hardness tests with neutron flux on different Silicon photomultiplier devices

Radiation hardness is an important requirement for solid state readout devices operating in high radiation environments common in particle physics experiments. The MEGII experiment, at PSI, Switzerland, investigates the forbidden decay $\mu^+ \to \mathrm{e}^+ \gamma$. Exploiting the most intense muon beam of the world. A significant flux of non-thermal neutrons (kinetic energy $E_k\geq 0.5 ~MeV$) is present in the experimental hall produced along the beamline and in the hall itself. We present the effects of neutron fluxes comparable to the MEGII expected doses on several Silicon PhotoMulitpliers (SiPMs). The tested models are: AdvanSiD ASD-NUV3S-P50 (used in MEGII experiment), AdvanSiD ASD-NUV3S-P40, AdvanSiD ASD-RGB3S-P40, Hamamatsu and Excelitas C30742-33-050-X. The neutron source is the thermal Sub-critical Multiplication complex (SM1) moderated with water, located at the University of Pavia (Italy). We report the change of SiPMs most important electric parameters: dark current, dark pulse frequency, gain, direct bias resistance, as a function of the integrated neutron fluency.Comment: 9 pages, 6 figures. Proceedings from Instrumentation for colliding Beam Physics (INSTR-17) 27-02-2017/03-03-2017 Novosibirsk (R

Lorentz violation and the proper-time method

In this paper, we apply the proper-time method to generate the Lorentz-violating Chern-Simons terms in the four-dimensional Yang-Mills and non-linearized gravity theories. It is shown that the coefficient of the induced Chern-Simons term is finite but regularization dependent.Comment: 11 pages, Revtex

Friedreich's ataxia-associated childhood hypertrophic cardiomyopathy: a national cohort study

OBJECTIVE: Hypertrophic cardiomyopathy (HCM) is an important predictor of long-term outcomes in Friedreich's ataxia (FA), but the clinical spectrum and survival in childhood is poorly described. This study aimed to describe the clinical characteristics of children with FA-HCM. DESIGN AND SETTING: Retrospective, longitudinal cohort study of children with FA-HCM from the UK. PATIENTS: 78 children (<18 years) with FA-HCM diagnosed over four decades. INTERVENTION: Anonymised retrospective demographic and clinical data were collected from baseline evaluation and follow-up. MAIN OUTCOME MEASURES: The primary study end-point was all-cause mortality (sudden cardiac death, atrial arrhythmia-related death, heart failure-related death, non-cardiac death) or cardiac transplantation. RESULTS: The mean age at diagnosis of FA-HCM was 10.9 (±3.1) years. Diagnosis was within 1 year of cardiac referral in 34 (65.0%) patients, but preceded the diagnosis of FA in 4 (5.3%). At baseline, 65 (90.3%) had concentric left ventricular hypertrophy and 6 (12.5%) had systolic impairment. Over a median follow-up of 5.1 years (IQR 2.4-7.3), 8 (10.5%) had documented supraventricular arrhythmias and 8 (10.5%) died (atrial arrhythmia-related n=2; heart failure-related n=1; non-cardiac n=2; or unknown cause n=3), but there were no sudden cardiac deaths. Freedom from death or transplantation at 10 years was 80.8% (95% CI 62.5 to 90.8). CONCLUSIONS: This is the largest cohort of childhood FA-HCM reported to date and describes a high prevalence of atrial arrhythmias and impaired systolic function in childhood, suggesting early progression to end-stage disease. Overall mortality is similar to that reported in non-syndromic childhood HCM, but no patients died suddenly

Blood Transfusion Requirement and not Preoperative Anaemia is associated with Perioperative Complications following Intracorporeal Robotic Assisted Radical Cystectomy

OBJECTIVES: To assess the prevalence of preoperative anaemia and the impact of preoperative anaemia and blood transfusion requirement on 30- and 90-day complications in a cohort of patients undergoing robotic assisted radical cystectomy with intracorporeal urinary diversion (iRARC). PATIENTS & METHODS: IRARC was performed on 166 patients between June 2011-March 2016. Prospective data was collected for patient demographics, clinical and pathological characteristics, perioperative variables, transfusion requirements and hospital length of stay. Thirty- and 90-day complications were classified according to the modified Memorial Sloan-Kettering Cancer Center Clavian-Dindo system. RESULTS: Preoperative anaemia was common (43.4%) and greatest in patients receiving neoadjuvant chemotherapy (48.6%) (p<0.001). Patients with preoperative anaemia were significantly more likely to have an Ileal conduit (p=0.033), higher cystectomy stage (≥pT3) (p=0.028) and a lower lymph node yield (p=0.031). Preoperative anaemia was not associated with increased perioperative morbidity but was associated with the need for blood transfusion (p=0.001). Blood transfusion was required in 20.4% of patients with intraoperative and postoperative blood transfusion rate was 10.2% and 13.9% respectively. The 30-day all complication rate and 30-day major complication rate was 55.4% and 15.7% respectively while 90-day all complication rate and 90-day major complication rate were 65.7% and 19.3% respectively. Intraoperative blood transfusion was not associated with increased complications but postoperative blood transfusion requirement was independently associated with perioperative morbidity: all 30 day complications (p=0.003), all 90-day complications (p=0.009) and 90-day major complications (p=0.004). CONCLUSION: The presence of preoperative anaemia in patients undergoing iRARC is not associated with increased surgical risk although preoperative anaemic patients were significantly more likely to require blood transfusion. Blood transfusion requirement and specifically postoperative blood transfusion is independently associated with perioperative morbidity and is an important factor for the optimisation of postoperative outcomes

Steps towards the hyperfine splitting measurement of the muonic hydrogen ground state: pulsed muon beam and detection system characterization

The high precision measurement of the hyperfine splitting of the muonic-hydrogen atom ground state with pulsed and intense muon beam requires careful technological choices both in the construction of a gas target and of the detectors. In June 2014, the pressurized gas target of the FAMU experiment was exposed to the low energy pulsed muon beam at the RIKEN RAL muon facility. The objectives of the test were the characterization of the target, the hodoscope and the X-ray detectors. The apparatus consisted of a beam hodoscope and X-rays detectors made with high purity Germanium and Lanthanum Bromide crystals. In this paper the experimental setup is described and the results of the detector characterization are presented.Comment: 22 pages, 14 figures, published and open access on JINS

Lorentz-violating Chern-Simons action under high temperature in massless QED

Lorentz and CPT violating QED with massless fermions at finite temperature is studied. We show that there is no ambiguity in the induced coefficient of the Chern-Simons-like term that defines the so-called Carroll-Field-Jackiw model at high temperature. We also show that this system constitutes an example where the breaking of CPT and Lorentz symmetries is more severe at high temperature than in the zero temperature case thus precluding any naive expectations of Lorentz symmetry restoration.Comment: 6 pages, 1 figure, final version to appear in Phys. Lett.