Development of the GRAiNITA prototype with ZnWO4 and BGO crystal grains Hull, G.; Boiaryntseva, I.; Lefrancois, J. ...
2023 IEEE Nuclear Science Symposium, Medical Imaging Conference and International Symposium on Room-Temperature Semiconductor Detectors (NSS MIC RTSD),
2023-Nov.-4
Conference Proceeding
We will present the development of two medium-size prototypes of GRAiNITA, a next-generation shashlik calorimeter, based on the use of ZnWO 4 and BGO crystal grains, respectively, soaked in a ...high-density and high-refractive index liquid. As in the LiquidO detection technique1, due to the presence of the grains, the scintillation light remains stochastically confined in the area of production; for this reason, it can be collected and transferred towards the photodetectors by the use of wavelength shifting fibers evenly distributed in the detection volume, similarly as in a conventional shashlik calorimeter.GRAiNITA represents a very appealing electromagnetic calorimeter candidate for high energy physics experiments for future electron-positron colliders. Indeed, due to the extreme fine sampling, GRAiNITA has the potential to reach a photon energy resolution of R~2%/sqrt(E) 2, thus increasing the precision of flavor physics with rare decays to photons or neutral pions. In this communication, we will present the outcomes of the study that led us to the choice of the best suited fibers for ZnWO 4 and BGO, respectively, and we will present the effect observed on the light propagation, when adding isopropanol in the detection volume (as a first approximation of future liquids), to fill the space between the crystal grains. Finally, we will discuss the development and characterization of the prototypes, presenting either the mechanical and the electronic design.
We perform model-independent statistical analyses of three scenarios accommodating new physics (NP) in Delta F = 2 flavor-changing neutral current amplitudes. In a scenario in which NP in B sub(d) - ...B sub(d) mixing and B sub(s) - B sub(s) mixing is uncorrelated, we find the parameter point representing the standard model disfavored by 2.4 standard deviations. However, recent LHCb data on B sub(s) neutral meson mixing forbid a good accommodation of the DO data on the semileptonic CP asymmetry A sub(SL). We introduce a fourth scenario with NP in both (ProQuest: Formulae and/or non-USASCII text omitted) and (ProQuest: Formulae and/or non-USASCII text omitted), which can accommodate all data. We discuss the viability of this possibility and emphasize the importance of separate measurements of the CP asymmetries in semileptonic B sub(d) and B sub(s) decays. All results have been obtained with the CKMfitter analysis package, featuring the frequentisi statistical approach and using Rfit to handle theoretical uncertainties.
The LHCb experiment (The LHCb Technical Proposal, CERN/LHCC 98-4) is designed to study B meson physics in the LHC proton–proton collider at CERN. The Scintillator Pad Detector (SPD) has been designed ...to complete the calorimeter information performing an
e
/
γ
identification for the experiment level-0 trigger system. The detection technology consists in transmitting scintillation light by means of both Wavelength Shifting and clear fibers to fast multi-anode photomultiplier tubes. In this paper, it is described the instrumentation and setup used to characterize the baseline photomultiplier solution (Hamamatsu R5900-00-M64) together with the scintillators and optical fibers for the SPD at LHCb.
The full LEP-1 data set collected with the ALEPH detector at the
Z pole during 1991–1995 is analysed in order to measure the
τ
decay branching fractions. The analysis follows the global method used ...in the published study based on 1991–1993 data, but several improvements are introduced, especially concerning the treatment of photons and
π
0
's. Extensive systematic studies are performed, in order to match the large statistics of the data sample corresponding to over 300
000 measured and identified
τ
decays. Branching fractions are obtained for the two leptonic channels and 11 hadronic channels defined by their respective numbers of charged particles and
π
0
's. Using previously published ALEPH results on final states with charged and neutral kaons, corrections are applied to the hadronic channels to derive branching ratios for exclusive final states without kaons. Thus the analyses of the full LEP-1 ALEPH data are combined to yield a complete description of
τ
decays, encompassing 22 non-strange and 11 strange hadronic modes. Some physics implications of the results are given, in particular related to universality in the leptonic charged weak current, isospin invariance in
a
1
decays, and the separation of vector and axial-vector components of the total hadronic rate. Finally, spectral functions are determined for the dominant hadronic modes and updates are given for several analyses. These include: tests of isospin invariance between the weak charged and electromagnetic hadronic currents, fits of the
ρ
resonance lineshape, and a QCD analysis of the non-strange hadronic decays using spectral moments, yielding the value
α
s
(
m
τ
2
)
=
0.340
±
0
.
005
exp
±
0
.
014
th
. The evolution to the
Z mass scale yields
α
s
(
M
Z
2
)
=
0.1209
±
0.0018
. This value agrees well with the direct determination from the
Z width and provides the most accurate test to date of asymptotic freedom in the QCD gauge theory.
The second generation experiment for CP violation studies in B decays, LHCb, is a 20-m-long single-arm spectrometer to be installed on the future Large Hadron Collider at CERN. For its precision ...measurement purpose, it combines precise vertex location and particle identification, in addition to a performance trigger system able to cope with high flux. The first level of trigger is mainly based on the fast response of the calorimetric subsystem. Of major importance is the 6000 channels preshower detector that aims to validate the electromagnetic nature of calorimetric showers. It consists of two-radiation-length lead sheet in front of a scintillator plane. Scintillator signals are extracted from plastic cells using wavelength-shifting fibres coupled to multi-anode photomultiplier tubes. The preshower Read Out system has to cope with fluctuating photomultiplier pulses caused by small amounts of photoelectrons, in addition to strong constraints imposed by the 40MHz LHC bunch-crossing frequency.
A special Read Out electronics including perfect 40MHz integrators able to shape fluctuating photomultiplier pulses has been designed, and successfully realized. The temporal shape of photomultiplier pulse and the upstream Read Out system for preshower are described in this document.
Abstract Objectives This study aimed to evaluate the frequency of diabetic ketoacidosis (DKA) and its associated factors at the diagnosis of type 1 diabetes (T1D) in French children and adolescents ...prior to launching a public-health campaign of information to prevent DKA. Patients and methods Over a 1-year period, 1299 youngsters (aged < 15 years) were diagnosed with T1D at 146 paediatric centres in all regions of France. Age, gender, duration of symptoms, patient's pathway to diagnosis, clinical and biological signs, and family history of T1D were collected for each newly diagnosed patient. DKA was defined as pH < 7.30 or bicarbonate < 15 mmol/L, and severe DKA as pH < 7.10 or bicarbonate < 5 mmol/L. Results At the time of diagnosis, 26% of the children were aged 0–5 years, 34% were 5–10 years and 40% were 10–15 years. The overall prevalence of DKA was 43.9% (0–5 years: 54.2%; 5–10 years: 43.4%; and 10–15 years: 37.1%) and 14.8% for severe DKA (0–5 years: 16.6%; 5–10 years: 14.4%; and 10–15 years: 13.9%; < 2 years: 25.3%). Severe DKA was more frequent when the child was hospitalized at the family's behest (26.6%) than when referred by a general practitioner (7.6%) or paediatrician (5.1%; 30.6%, 53.7% and 9.2%, respectively, by patients’ age group). The frequency of DKA decreased to 20.1% (severe DKA: 4.4%) in families with a history of T1D. Multivariate analysis showed that age, pathway to diagnosis, duration of polyuria/polydipsia (< 1 week) and family history of T1D were associated with the presence of DKA, while pathway to diagnosis and family history of T1D were associated with severe DKA. Conclusion DKA at the time of T1D diagnosis in children and adolescents is frequent and often severe. Patients’ age, pathway to hospitalization and family history of diabetes were the main factors associated with DKA. These data suggest that a public-health campaign to prevent DKA at diagnosis can help reduce the frequency of DKA and also provide baseline data for evaluating the efficacy of such a campaign.
The production cross-section of J/ψ pairs is measured using a data sample of pp collisions collected by the LHCb experiment at a centre-of-mass energy of s√=13TeV, corresponding to an integrated ...luminosity of 279±11pb−1. The measurement is performed for J/ψ mesons with a transverse momentum of less than 10GeV/c in the rapidity range 2.0<y<4.5. The production cross-section is measured to be 13.5±0.9±0.8nb. The first uncertainty is statistical, and the second is systematic. The differential cross-sections as functions of several kinematic variables of the J/ψ pair are measured and compared to theoretical predictions.
The Lhcb experiment will study the CP symmetry violation in the system of the beauty particles. The detector is a 20-m-long spectrometer, to be installed on the proton–proton collider Lhc. Of major ...importance for the level 0 trigger is the preshower of the electromagnetic calorimeter designed to discriminate between electrons, hadrons and photons. The preshower cells consist of a two-radiation-length lead sheet located between two plastic scintillator planes. The scintillation light is extracted with wavelength-shifting fibres. The best candidates to read out the light of the 6000 detector cells are multianode photomultipliers. The HAMAMATSU photomultiplier R5900-00-M64 has been studied and its responses in terms of gain, linearity, uniformity within and between the anodes and cross-talk between the channels are addressed in this document.
A search for the rare decays B0s→τ+τ− and B0→τ+τ− is performed using proton--proton collision data collected with the LHCb detector. The data sample corresponds to an integrated luminosity of 3fb−1 ...collected in 2011 and 2012. The τ leptons are reconstructed through the decay τ−→π−π+π−ντ. Assuming no contribution from B0→τ+τ− decays, an upper limit is set on the branching fraction B(B0s→τ+τ−)<6.8×10−3 at 95\% confidence level. If instead no contribution from B0s→τ+τ− decays is assumed, the limit is B(B0→τ+τ−)<2.1×10−3 at 95\% confidence level. These results correspond to the first direct limit on B(B0s→τ+τ−) and the world's best limit on B(B0→τ+τ−).
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