arXiv subjects

A. Milov

Publications and source records attributed to A. Milov.

12 recordsLinked to original sources

arXiv2023

The effects of a passive Bi-Polar Grid (BPG) on Ion Back-Flow (IBF) and Resolution

Time Projection Chambers (TPC)s are excellent tracking detectors for high multiplicity events and can intrinsically be high-rate, but are limited by the ions created in their avalanche stage. GEMs and Micromegas can reduce IBF through their geometry and E-field ratios, but these can lead to gain fluctuations and still leave IBF as the dominant source of space charge. An active BPG can block all IBF ions, but their slow drift speed creates too much dead time. A passive BPG will overcome this limitation by using an external B-field to allow the electrons to pass through while still blocking all ions. Since the grid changes the electron's trajectory, a loss of resolution will occur. The trajectory is shifted symmetrically along the wires so the wire alignment with respect to the detection pads is a specific question not studied before. We present completed IBF analysis from data collected at Weizmann Institute of Science (WIS), along with an intro to our test on wire resolution.

physics.ins-det↗

arXiv2022

Letter of Intent: the NA60+ experiment

We propose a new fixed-target experiment for the study of electromagnetic and hard probes of the Quark-Gluon Plasma (QGP) in heavy-ion collisions at the CERN SPS. The experiment aims at performing measurements of the dimuon spectrum from threshold up to the charmonium region, and of hadronic decays of charm and strange hadrons. It is based on a muon spectrometer, which includes a toroidal magnet and six planes of tracking detectors, coupled to a vertex spectrometer, equipped with Si MAPS immersed in a dipole field. High luminosity is an essential requirement for the experiment, with the goal of taking data with 10$^6$ incident ions/s, at collision energies ranging from $\sqrt{s_{\rm NN}} = 6.3$ GeV ($E_{\rm lab}= 20$ A GeV) to top SPS energy ($\sqrt{s_{\rm NN}} = 17.3$ GeV, $E_{\rm lab}= 158$ A GeV). This document presents the physics motivation, the foreseen experimental set-up including integration and radioprotection studies, the current detector choices together with the status of the corresponding R&D, and the outcome of physics performance studies. A preliminary cost evaluation is also carried out.

nucl-ex↗

arXiv2019

Passive Gating Grid for Ion Back Flow Suppression in High Luminosity Collider Experiments

Time Projection Chamber (TPC) is one of the main tracking systems for many current and future collider experiments at RHIC and LHC. It has a capability to measure the space points of charged tracks for good momentum resolution as well as the energy loss (dE/dx) for particle identification with good energy resolution. Both of these features depend strongly on the amount of space charge in the TPC gas volume, mainly due to the ions from the amplification stage. An active gating grid has been used thus far to gate the electrons and ions by switching the polarities of the grid wires. Therefore, active gating does introduce a limitation for data taking rates in high luminosity collisions. In this work we propose several options of a passive gating, where a significant reduction of Ion Back Flow (IBF) is possible in a high luminosity environment without any dead time issues due to gating operation. Particularly, the application of a TPC passive gating for the sPHENIX experiment at RHIC is presented, which is currently under development.

physics.ins-det↗

arXiv2011

Design, Construction, Operation and Performance of a Hadron Blind Detector for the PHENIX Experiment

A Hadron Blind Detector (HBD) has been developed, constructed and successfully operated within the PHENIX detector at RHIC. The HBD is a Cherenkov detector operated with pure CF4. It has a 50 cm long radiator directly coupled in a window- less configuration to a readout element consisting of a triple GEM stack, with a CsI photocathode evaporated on the top surface of the top GEM and pad readout at the bottom of the stack. This paper gives a comprehensive account of the construction, operation and in-beam performance of the detector.

physics.ins-det↗

arXiv2011

Predictions of hadron abundances in pp collisions at the LHC

Based on the statistical hadronization model, we obtain quantitative predictions for the relative abundances of hadron species in pp collisions at the LHC. By using the parameters of the model determined at sqrt s = 200 GeV, and extrapolating the overall normalization from ppbar collisions at the SPS and Tevatron, we find that the expected rapidity densities are almost grand-canonical. Therefore, at LHC the ratios between different species become essentially energy-independent, provided that the hadronization temperature T_H and the strangeness suppression factor gamma_S retain the stable values observed in the presently explored range of pp and ppbar collisions.

hep-ph↗

arXiv2010

A comparative analysis of statistical hadron production

We perform a systematic comparison of the statistical model parametrization of hadron abundances measured in high energy pp, AA and e+e- collisions. The basic aim of the study is to test if the quality of the description depends on the nature of the collision process. In particular, we want to see if nuclear collisions, with multiple initial interactions, lead to "more thermal" average multiplicities than elementary pp collisions or e+e- annihilation. Such a comparison is meaningful only if it is based on data for the same or similar hadronic species and if the analyzed data has quantitatively similar errors. When these requirements are maintained, the quality of the statistical model description is found to be the same for the different initial collision configurations.

hep-ph↗

arXiv2006

Global Observables at RHIC

Main characteristics of the charged particle dN_ch/deta and transverse energy dE_T/deta production measured in Heavy Ion collisions at RHIC energies are presented in this article. Transformation of the pseudo-rapidity shape, relation to the incident energy and centrality profile are described in a systematic way. Centrality profile is shown to be closely bound to the number of nucleons participating in the collisions, at the same time an alternative approach to study the centrality behavior is also discussed.

nucl-ex↗

arXiv2006

Hadron Blind Detector for the PHENIX Experiment at RHIC

The PHENIX collaboration has designed a conceptually new Hadron Blind Detector (HBD) for electron identification in high density hadron environment. The HBD will identify low momentum electron-positron pairs to reduce the combinatorial background in the mass region below 1 GeV/c^2. The HBD shall be installed in PHENIX during the 2007 physics run. The HBD is a windowless proximity focusing Cherenkov detector with a radiator length of 50 cm, CsI photocathode and three layers of Gas Electron Multipliers (GEM) for gas amplification. Pure CF_4 serves both as a radiator and as a detector gas. The radiation budget of the device is less than 3% of a radiation length.

nucl-ex↗

arXiv2005

A Hadron Blind Detector for the PHENIX Experiment at RHIC

A Hadron Blind Detector (HBD) is being developed for the PHENIX experiment at RHIC. It consists of a Cherenkov radiator operated with pure CF4 directly coupled in a windowless configuration to a triple-GEM detector element with a CsI photocathode and pad readout. The HBD operates in the bandwidth 6-11.5 eV(110-200 nm). We studied the detector response to minimum ionizing particles and to electrons. We present measurements of the CsI quantum efficiency, which are in very good agreement with previously published results over the bandwidth 6-8.3 eV and extend them up to 10.3 eV. Discharge probability andaging studies of the GEMs and the CsI photocathode in pure CF4 are presented.

physics.ins-det↗

arXiv2004

Centrality and $\sqrt{s_{NN}} Dependence of the $dE_{T}/dη$ and $dN_{ch}/dη$ in Heavy Ion Collisions at Mid-Rapidity

The PHENIX experiment at RHIC has measured transverse energy and charged particle multiplicity at mid-rapidity in Au + Au collisions at $\sqrt{s_{NN}}$ = 19.6, 130, 62.4 and 200 GeV as a function of centrality. The presented results are compared to measurements from other RHIC experiments, and experiments at lower energies. The $\sqrt{s_{NN}}$ dependence of $dE_{T}/dη$ and $dN_{ch}/dη$ per pair of participants is consistent with logarithmic scaling for the most central events. The centrality dependence of $dE_{T}/dη$ and $dN_{ch}/dη$ is similar at all measured incident energies. At RHIC energies the ratio of transverse energy per charged particle was found independent of centrality and growing slowly with $\sqrt{s_{NN}}$. A survey of comparisons between the data and available theoretical models is also presented.

nucl-ex↗

arXiv2003

Proposal for a Hadron Blind Detector for PHENIX

A Hadron Blind Detector (HBD) is proposed as upgrade of the PHENIX detector at RHIC, BNL. The HBD will allow the measurement of low-mass e+e- pairs from the decay of the light vector mesons rho, omega, phi and the low-mass continuum in Au-Au collisions at energies up to sqrt{s_{NN}}= 200 GeV. From MC simulations and general considerations, the HBD has to identify electrons with very high efficiency (> 90%), double hit recognition better than 90%, moderate pion rejection factor of ~200 and radiation budget of the order of 1% of a radiation length. The first choice under study is a windowless Cherenkov detector, operated with pure CF4, in a special proximity focus configuration with a CsI photocathode and a multistage GEM amplification element.

physics.ins-det↗

arXiv2001

Charged particle multiplicity and transverse energy in Au - Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV

This paper presents the results for the charged-particle multiplicity and transverse energy distributions at mid-rapidity in Au - Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV measured with the PHENIX detector at RHIC. The values of $dN_{ch}/dη_{|η=0}$ and $dE_{T}/dη_{|η=0}$, analyzed as a function of centrality, show a consistent steady rise. For the 5% most central collisions they are $\sim70$% larger compared to the SPS results for Pb-Pb collisions at $\sqrt{s_{_{NN}}}=17.2$ GeV. The ratio of $ / $ remains constant as a function of centrality at 0.8 GeV, as also observed at the SPS at CERN and at the AGS at BNL.

nucl-ex↗