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From CATE to LYCCA

From CATE to LYCCA. Particle Identification After the Secondary Target. Mike Taylor. 58 Ni 600 MeV/u ~ 5x10 8 pps. 9 Be 4 g/cm 2 production target. 55 Ni ~ 175 MeV/u ~ 4x10 3 pps. 9 Be 700 mg/cm 2 secondary target. Rising Fast Beam Campaign.

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From CATE to LYCCA

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  1. From CATE to LYCCA Particle Identification After the Secondary Target Mike Taylor

  2. 58Ni 600 MeV/u ~ 5x108 pps 9Be 4 g/cm2 production target 55Ni ~ 175 MeV/u ~ 4x103 pps 9Be 700 mg/cm2 secondary target Rising Fast Beam Campaign Proposed experiment: (M. A. Bentley, Oct 2003) “Isospin Symmetry and Coulomb Effects Towards the Proton Drip-Line” • g ray spectroscopy of exotic proton rich nuclei • Study the T=3/2 mirror nuclei 53Mn/53Ni, basis for Ph. D. thesis (G. Hammond) • Analyse, correct and put • the data into a form in which • it can be compared to simulations • Investigate properties that contribute to fragment ID • such as the origin and extent of energy and velocity spreads

  3. Range of nuclei produced • Many nuclei produced with greater or comparable intensity • to the proposed nucleus of interest 53Ni • Allows a systematic study of nuclear properties across a • range of nuclei and isotopes • Possibility of new γ-ray spectroscopy: • 45Cr : No γ transitions observed • 43V : Nothing observed, last proton • only bound by ~120 keV

  4. Particle Identification Detector (CATE) CAlorimeter TElescope (CATE) consists of an array of 9 position sensitive Si detectors (DE) and an array of 9 CsI detectors (E) • Si detectors • 5cm x 5cm x 300μm • Fragment energy loss • (X,Y) position information • (after corrections for “pin • cushion” effect) • CsI detectors • 5.4cm x 5.4cm x 1cm • Fragment energy (after position dependence correction) Si position correction implemented by G. Hammond

  5. Requirements for Fragment ID • Z resolution from energy loss • A resolution from total energy Ni Mg

  6. Isotopic Separation From Total Implantation Energy • Cate energy corrected for beam • energy spread • Don’t see distinct peaks corresponding • to the isotopes with comparable cross- • sections • Cross-sections from • EPAX 2.1 47V : σ ~ 19 mb48V : σ ~ 20 mb 49V : σ ~ 9 mb 52Fe : σ ~ 30 mb 53Fe : σ ~ 50 mb

  7. Iron Analysis 52Fe * * 53Fe * * * * * • Event-by-event tracking and β determination • Doppler corrected, time gated and background subtracted • NO mass gate 53Fe: E(9/2–→7/2–) = 1328 keV E(11/2–→9/2–) = 1011 keV E(5/2–→1/2–) = 683 keV 52Fe: E(2+→0+) = 849 keV E(4+→2+) = 1535 keV

  8. a) b) c) d) d b a c Mass Gated Gamma Spectra • Apply a series of gates on the corrected Total Cate energy spectrum • Project out the associated gammas • Clear differences in the resulting spectra are • observed with varying Cate energy cuts • Low statistics due to small cut regions

  9. Mass Gated Fe Gamma Spectra • To improve statistics can apply larger cuts, again different gamma spectra emerge • 53Fe gamma at 861 keV

  10. 52Fe Gamma Spectrum • Scaled 53Fe background spectrum subtracted (2+→0+) (4+→2+)

  11. Fe Gamma Gated Mass Spectra 7506 7610 52Fe 53Fe 53Fe: FWHM = 2.75% • Lot of work done on this topic by R. Lozeva:NIM A562, 298 (2006) • For fragmentation, resolution quoted as being between 2-3% FWHM

  12. Vanadium Analysis 49V * 48V * • Same conditions as for the Fe analysis • Again NO mass gate applied here * 49V: E(11/2–→7/2–) = 1022 keV 48V: E(5+→4+) = 428 keV E[(7+→6+),(6+→4+)] = 628,627 keV * *

  13. V Gamma Gated Mass Spectra • Isotopic separation not clear • Goldhaber spread increases with nucleon removal 48V: FWHM = 5.5% 48V 49V

  14. Nickel Analysis • Without clear isotopic separation it is extremely difficult to produce • clean gamma-ray spectra for low cross-section isotopes • Cannot determine to which nucleus new gammas belong * 54Ni: E(2+→0+) = 1392 keV E(4+→2+) = 1227 keV * 54Ni : σ ~ 5 mb 53Ni : σ ~ 0.009 mb

  15. Population of Excited Nuclear States investigated by In-Beam Gamma-Ray Spectroscopy of Relativistic Projectile FragmentsF. Becker et al., to be submitted toEPJ • Comparison between calculations and experiment • ABRABLA: population intensity as a function of spin

  16. Difficult to perform γ-ray spectroscopy on neutron deficient nuclei • without mass information • Limited spectroscopic information can be gained but only after many • corrections and analysis tricks • Goldhaber spread increases with nucleon removal so things become • even more difficult when studying nuclei from more than 1 or 2 particle • removal Simple Job NOT Good Enough ! • Need more information along with total energy to obtain good mass • identification such as Time-of-Flight

  17. Lund-York-Cologne CAlorimeter (LYCCA) • Diamond ? • Stop TOF • Diamond ? • Start TOF DSSD’s Light particle energy detection CsI detectors particle energy (E) detection DSSD’s particle energy loss (ΔE) • Two modules • LCP detection ii) Fragment identification beam from Super FRS DSSD’s: 6cm x 6cm, 32 x 32 strips • Fragment identification • from ΔE, E and TOF CsI’s: 2cm x 2cm, 3 x 3 x 3 array 1.1 cm thick

  18. Simulation ofCATE: Geant4 + ROOT • Si: 9 detectors • 5cm x 5cm x 300μm • CsI: 9 detectors • 5.4cm x 5.4cm x 1cm • 58Ni (215 MeV/u) beam • After SC41 158.46 MeV/u • E loss through 300μm Si • Test the sensitive detector • response with a simple • simulation

  19. Implementation of Timing Detectors • Signals Collected: • Si & CsI • x,y position • energy • segment number • Diamond • x,y position • energy • time • Diamond (CVD) timing detectors • 16cm x 16cm x 100μm • Diamond detector distance • Tgt-Si expt 1.44m • Sim also: 2m, 3m • Max: 3.5m • Si energy resolution: 1.6% FWHM • CsI energy resolution: 1% FWHM • Diamond energy resolution: 1% FWHM • Diamond time resolution: 50ps FWHM Need to simulate fragments after the secondary reaction !

  20. MOCADI as an Event Generator • Monte Carlo code to model ion transport and energy loss (uses ATIMA 1.0) • (Nuc. Inst. & Meth. in Phys. Res. B 126, 284) • Used to optimise experimental setup of FRS at GSI • Models fragmentation reactions using Goldhaber momentum distribution • (Phys. Lett. 53B, 306) (uses EPAX2 for cross-sections) • Option to output events to an ASCII file (no cross-sections applied !) • Variables outputted • Fragment number • X-position (cm) • X angle (mrad) • Y-position (cm) • Y angle (mrad) • Energy (AMeV) • Time (ps) • Mass (amu) • Z • Charge state

  21. Generation of Simulation Event File

  22. Simulation Results: Fragment XY Distribution Fragment x,y distribution across the nine Si detectors of CATE

  23. Fragment Identification From Energy Signals Simulation Data Fragments + unreacted beam • 175 MeV/u 55Ni beam • 130000 primary events • 700 mg/cm29Be target • 91 fragments produced • with cross-sections > 10-2 mb • (Z range: Ni – S) • Tgt-Si distance 2.02m Simulation Ni Co : : : Ti : : S Fragments only NO gamma gate on sim !

  24. Si Detector Energy Signals Fragment yield varies with scattering angle due to number of protons removed

  25. CsI Detector Energy Signals Fragment yield varies with scattering angle due to number of nucleons removed

  26. Analysis of Time Signals • Separation better at 3m due to • timing resolution being better as a • percentage of the total TOF • Separation worse at high energy • due to the resolution being a • percentage of the deposited • energy TOF distance =2m 3m

  27. Calculation of Mass from TOF and Energy Using the TOF and energy of each detected fragment the mass can be calculated directly using a formula. The improvement of resolution with TOF distance is clear

  28. ROOT Analysis File Structure • Raw signal and • diagnostic spectra • created and filled • directly • Raw and selected • correlated signals • written to a ROOT • TTree object for • further analysis

  29. Cobalt Gated TOF vs Energy • At 2m TOF distance mass • separation just visible • At 3m, separation between • the two isotopes with the • largest cross-sections is • much cleaner • All cross-sections from EPAX2

  30. Titanium Gated TOF vs Energy • At 2m the mass separation • is better than the Co case • but still a little dirty • At 3m the separation is • approaching an ideal case

  31. Sulphur Gated TOF vs Energy

  32. A~100 Investigation • 102Sn + 9Be, 175 MeV/u • same profile as 55Ni beam • 700 mg/cm2 target • Fragments only (56) • no unreacted beam simulated Sn In Cd Ag Pd Rh • TOF distance set to max 3.5m • Energy & time resolutions • unchanged • No clear mass separation from • total TOF vs Energy plot

  33. Cadmium Gated TOF vs Energy All fragments Cd gated • A crude mass gate • could be applied but • this is close to the • limit of this technique

  34. (Lots) To Do: (simulation wise) • Fix TOF distance to investigate detector resolution effects • Test other timing options: Diamond – Si, Diamond – Scintilator • Change to prototype geometry • Simulate with Super FRS beam profile • Simulate test experiments with final setup • e.g. • Integrate simulation into full HISPEC simulation

  35. Towards a LYCCA Prototype (2x3)x(3x3) Array of 2 x 2 cm CsI Detectors located 1cm behind the Si array Scintillators are 1.1 cm thick 0.7 cm behind which are located 1 x 1 cm photodiodes (2x3) Array of 6 x 6 cm DSSD’s

  36. LYCCA - 0: The Prototype • 2 x 4 Array of telescope modules • Test different timing detectors • Scintillator, Diamond, Silicon

  37. Project Timeline • Jan 2007: • 1 test module assembled • Spring 2007: • Test module to undergo in-beam tests • 2008: • 2 x 4 array, LYCCA-0 ready for use in next Rising • Fast Beam Campaign. Used to test timing options Collaborators M. A. Bentley, University of York D. Rudolph, R. Hoischen, P. Golubev, Lund University P. Reiter, University of Köln J. Gerl, M. Górska, GSI Laboratory + Rising Collaboration, GSI + NUSTAR Simulation group

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