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SUMMARY:Warsaw active target TPCs for studying astrophysical reactions
DTSTART:20260212T090000Z
DTEND:20260212T110000Z
DTSTAMP:20260417T154000Z
UID:indico-event-1348@indico.hiskp.uni-bonn.de
DESCRIPTION:Speakers: Mikolaj Cwiok (University of Warsaw)\n\nAbstract: \
 nIn the seminar I will present a detector R&D programme carried out at the
  University of Warsaw (Poland) in collaboration with: University of Connec
 ticut (USA)\, ELI-NP/IFIN-HH (Romania) and Sheffield Hallam University (UK
 ) dedicated to study (proton\,gamma) and (alpha\,gamma) nuclear reactions 
 of astrophysical interest\, which regulate abundance ofcarbon and oxygen e
 lements in the Universe.\nIn particular\, the production of Oxygen-16 and 
 burning of Carbon-12 via the 12C(alpha\,gamma)16O reaction takes place in 
 stars at energies close to the Gamow peak. Typical direct measurements of 
 this benchmark reaction suffer from maximal available ion beam currents an
 d target deterioration. Instead\, thanks to the principle of detailed bala
 nce in nuclear reactions\, one can measure time-reverse reactions induced 
 by intense semi-monochromatic gamma beams. For this purpose we have develo
 ped a Time Projection Chamber (Warsaw TPC) with active gaseous target kept
  at low pressure\, in which collimated gamma-ray photons can react with nu
 clei of the gas. The kinematics of outgoing charged particles is reconstru
 cted on event-by-event basis from specially arranged\, redundant signal st
 rip arrays (u-v-w).\nFirst experiments were conducted in years 2020-2022 w
 ith gamma-ray beams from the High Intensity Gamma-Ray Source (HIgS) facili
 ty\, Triangle Universities Nuclear Laboratory\, Durham\, NC\, USA\, as wel
 l as with the neutron beam from the IGN-14 neutron generatorat the Institu
 te for Nuclear Physics\, Polish Academy of Science\, Cracow\, Poland.\nIn 
 the presentation I will focus on the results on Oxygen-16 photo-disintegra
 tion reaction from the experiment conducted at HIgS for the gamma beam ene
 rgies corresponding to nominal centre-of-mass energies from 6.7 MeV down t
 o 1.35 MeV. The relative contributions of E1 and E2 components and E1+E2 c
 ross sections were extracted from the measured angular distributions at di
 fferent gamma beam energies. The results are based on a simplified event r
 econstruction algorithm after analysing only partial statistics available\
 , while work on more sophisticated data processing is still ongoing.\nA ne
 w multi-purpose version of the TPC apparatus that can study nuclear proces
 ses with radioactive ion beams\, in addition to gamma-ray and neutron beam
 s\, will be discussed as well.\n \nJoin Zoom Meetinghttps://uni-bonn.zoom
 -x.de/j/66253567797?pwd=R2MrNmNCQnl4K1hSejd6VnBEYXJ2QT09\nMeeting ID: 662 
 5356 7797Passcode: 599591\n\nhttps://indico.hiskp.uni-bonn.de/event/1348/
URL:https://indico.hiskp.uni-bonn.de/event/1348/
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