Ota Kukral

Studies of Cathode Strip Chamber longevity, comparing Ar+CO2 gas mixtures with fractions of 5%, 2%, and 0% CF4, were performed using several small cathode strip prototype chambers. In each trial, a localized source of radiation was used to irradiate up to an accumulated charge of about 300 mC/cm. Additionally, longevity of a uniformly irradiated prototype operating with 2% CF4 was studied at the CERN Gamma Irradiation Facility GIF++. Post-hoc analysis of the chamber electrodes using spectroscopy techniques was also done.

Abstract Studies of cathode strip chamber longevity, comparing Ar+CO $$_2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow /> <mml:mn>2</mml:mn> </mml:msub> </mml:math> gas mixtures with fractions of 5%, 2%, and 0% CF $$_4$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow /> <mml:mn>4</mml:mn> </mml:msub> </mml:math> , were performed using several small cathode strip prototype chambers. In each trial, a localized source of radiation was used to irradiate up to an accumulated charge of about 300 mC/cm. Additionally, longevity of a uniformly irradiated prototype operating with 2% CF $$_4$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow /> <mml:mn>4</mml:mn> </mml:msub> </mml:math> was studied at the CERN Gamma Irradiation Facility GIF++. Post-hoc analysis of the chamber electrodes using spectroscopy techniques was also done.

Extensive studies of quark-gluon plasma (QGP), the novel state of strongly interacting matter governed by partonic degrees of freedom, have been conducted at RHIC for over a decade.Suppression of quarkonia production in high energy nuclear collisions relative to proton-proton collisions, due to Debye screening of the quark-antiquark potential, has been predicted to be a sensitive indicator of the temperature of the created QGP.However, cold nuclear matter effects, production via recombination of quark-antiquark pairs in the QGP and dissociation in hadronic phase could also alter the observed quarkonia yields.Indeed, recent measurements in Au+Au and d+Au collisions at RHIC show that these effects play a non-negligible role.Hence systematic measurements of the quarkonia production for different colliding systems are crucial for understanding the quarkonium interactions with the partonic medium, and then the QGP properties.To further study the pattern of quarkonia suppression we can utilize the collisions of non-spherical nuclei such as uranium.In this paper, we will present the analysis status on J/ψ production, measured at midrapidity via di-electron decay channel, in U+U collisions at √ s NN = 193 GeV in the STAR experiment.

Extensive studies of quark-gluon plasma (QGP), the novel state of strongly interacting matter governed by partonic degrees of freedom, have been conducted at RHIC for over a decade. Suppression of quarkonia production in high energy nuclear collisions relative to proton-proton collisions, due to Debye screening of the quark-antiquark potential, has been predicted to be a sensitive indicator of the temperature of the created QGP. However, cold nuclear matter effects, production via recombination of quark-antiquark pairs in the QGP and dissociation in hadronic phase could also alter the observed quarkonia yields. Indeed, recent measurements in Au+Au and d+Au collisions at RHIC show that these effects play a non-negligible role. Hence systematic measurements of the quarkonia production for different colliding systems are crucial for understanding the quarkonium interactions with the partonic medium, and then the QGP properties. To further study the pattern of quarkonia suppression we can utilize the collisions of non-spherical nuclei such as uranium. In this paper, we will present the analysis status on J=y production, measured at midrapidity via di-electron decay channel, in U+U collisions at p sNN = 193 GeV in the STAR experiment.