BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Radiation Shielding calculations using MCNPX transport code for co
 st optimization of the shielding material to be used in the new cyclotron 
 vault at iThemba Labs
DTSTART;VALUE=DATE-TIME:20110714T150000Z
DTEND;VALUE=DATE-TIME:20110714T170000Z
DTSTAMP;VALUE=DATE-TIME:20260711T210825Z
UID:indico-contribution-5136@events.saip.org.za
DESCRIPTION:Speakers: Zipho Ngcobo (iThemba Labs)\nIon Beam Applications (
 IBA) commercial cyclotron (IBA Cyclone 70) with capability of accelerating
  protons up to 70MeV and 350µA of current is to be constructed at iThemba
  Labs to increase the capacity of the current facility. The two opposite s
 imultaneous extraction of beams using the Carbon foil stripper\, enable fo
 r the concurrent production of radioactive ion beam (RIB) for nuclear rese
 arch and isotope production.\nThis high energy beam is expected to have lo
 sses of about 10% in total meaning 70µA of the total beam will interact w
 ith surrounding materials during acceleration. Thus this proton beam is a 
 possible radiation source\, presenting a threat of ionising radiation. The
  cyclotron is mainly made of magnetic steel which is rather stable provind
 ing local shielding inside the vault. There are not many significant openi
 ngs for the radiation to rather escape in the less dense media to the surr
 ounding other than in the extraction sides. Between the two poles of the c
 yclotron\, the strip made of steel\, which seals the two poles\, is thick 
 enough to shield radiation. Considering efficiencies at the extraction sid
 e of the cyclotron\, it is expected that radiation contamination will accu
 mulate and be transported to the vault and surroundings during cyclotron o
 perations.\nParticles of concern are neutrons and photons formed during pr
 oton beam interaction. Bremstrahlung x-rays (photons) could be from proton
  acceleration and neutrons could be produced by (p\, n) reactions. Photons
  and neutrons are not easy to shield. There is a need to simulate the radi
 ation transport using MCNPX transport code so that the levels of doses can
  be investigated to provide extra safety cautions and adequate selection o
 f materials and correct dimensions for shielding walls to keep the dose ra
 tes at acceptable levels.  Additionally\, water in the cooling system as i
 t consists of Hydrogen isotopes that can react with protons to produce neu
 trons will also be investigated as it will increase the neutron flux into 
 the vault.\n\nhttps://events.saip.org.za/event/7/contributions/5136/
LOCATION: Asteria
URL:https://events.saip.org.za/event/7/contributions/5136/
END:VEVENT
END:VCALENDAR