Possibilities for AMS experiments at ATLAS Philippe Collon, University of Notre Dame

Present status of AMS experiments at ATLAS A number of AMS experiments have been performed at ATLAS – Environmental science ( 39 Ar, 81 Kr, …) – Stellar nucleosynthesis ( 59 Ni, 62 Ni(n,  ) 63 Ni, 146 Sm, 182 Hf,…) – WIMP dark matter detector development ( 39 Ar) AMS relies on a number of factors – Good isobaric separation – Stability of the entire system – High overall transmission

146 Sm 146 Nd 146 Sm/ 147 Sm ~ Sm t 1/2 measurement using AMS 146 Sm- 146 Nd separation PII ECR-II BOOSTER LINAC ATLAS LINAC FN TANDEM INJECTOR EC R-I GFM Spectrograph 146 Sm 22+ / 146 Nd MeV Detection of live 146 Sm in meteorites may also be an interesting capability

Blocking Shield Ionization Chamber  E 1 -  E 5 Beam Gas-Filled Magnet † 10 Torr N 2 Faraday Cup PGAC Target Chamber Position-Sensitive Parallel-Grid Avalanche Counter Gas Filled Magnet (GFM) Spectrograph 146 Nd 146 Sm 80 Kr 152 Sm 23+

High sensitivity 59 Ni AMS using full stripping 59 Ni- 59 Co separation ECR: 59 Ni 16+ (~3%) 630 MeV 1mg/cm 2 C stripper foil 10% fully stripped Natural production of 59 Ni (t 1/2 = 76 kyr) occurs by interaction of cosmic-ray particles with matter. This production is signficant only in extraterrestrial matter and concentrations of the order of 59 Ni/Ni = – have been measured in iron meteorites by AMS

List of commonly classified p-nuclides NucleusabundanceNucleusabundancenucleusabundance 74Se Sn Dy Kr Sn Dy Sr Te Er Mo Xe Er Mo Xe Yb Ru Ba Hf Ru Ba Ta2.4e Pd La W Cd Ce Os Cd Ce Pt In Sm Hg Sn Gd Stellar production rates can be studied using the inverse (  ) reactions followed by AMS counting of produced nuclei

Short-lived cosmogenic radionuclides AIsotope  t 1/2 (years)Mass 1010Be E Al E Cl E Ca E Mn E Fe E Se E Kr E Zr E Tc E Tc E Tc E Sn E Cs E Sm Gd E Dy E Hf E Bi E Bim E U E U E Np E Np E Pu E Cm E

AMS possibilities with the upgraded facility A number of the radionuclides can be detected using smaller accelerators however a large number of very exciting nuclides will “benefit” from an ATLAS upgrade Higher beam currents – Reduce count times (less stability requirements) – Allow access to lower reaction cross sections – Improve sensitivity Higher beam energies (  improved isobaric separation) – Improved separation for gas-filled magnet techniques – Higher full-stripping probabilities

182 Hf as an supernova indicator 182 Hf is a r-process radionuclides with a rapid s-process component in massive stars. During supervovae events it can be injected into the interstellar medium t 1/2 = 9x10 9 years Its signal should be detectable in geological material: Needs separation from 182 W

Possible needs for upcoming AMS experiments at ATLAS Possibility of “clean” ion sources with the development of plasma chamber liner (Quartz) and/or the development of a dedicated quartz lined ECR source Development of a new detector that can accommodate higher count rates Improved continuous beam monitoring (both for transmission and primary beam intensity) Further development of calibrated beam attenuation (tested during recent 146 Sm experiments) …..