29042019 1 ASSIE Marlne Io P Recoil spectrometer

29/04/2019 1 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Recoil spectrometers for transfer reactions ? Marlène Assié IPN Orsay, assie@ipno. in 2 p 3. fr ©CEA/P. Stroppa

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Transfer reactions in inverse kinematics • Typical energies: 5 - 15 Me. V/u. • Typical intensities: > few 104 up to 106 -7 pps (d, p) from 180° to forward of 80° INCIDENT BEAM (d, d) Just forward of 90° (d, t) forward of 45° 2

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Transfer reactions in inverse kinematics • Typical energies: 5 - 15 Me. V/u. • Typical intensities: > few 104 up to 106 -7 pps (d, p) from 180° to forward of 80° INCIDENT BEAM Transfer products on neutron-rich side can sequentially n-decay (filling a bigger cone) (with smaller momentum) (d, t) forward of 45° + other things, Knock-on carbons from CD 2 targets (d, d) Just forward of 90° Isobaric beams can be identified and/or physically separated (possibly further stripped by the target ) Adapted from W. Catford 3

ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Characteristics of transfer reactions with light targets • Device at 0 degree -->Small scattering angles around 0 • Performances : . Event-by-event PID: Physical separation of reaction products of interest - from the beam / isobaric beam contaminants and others - from fusion-evaporation reactions with target (CH 2, CD 2, X+3 H, X+4 He, X+16 O, …). Large acceptance. Excellent angular resolution to allow kinematic reconstruction (and Doppler correction). A/Z resolution : ? . Timing : useful for particle identification in some cases … Normalisation - Beam composition (if not pure) - Integral measurement sufficient but beam tracking devices useful (BTD limited to 105 pps)

29/04/2019 5 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 MUGAST commissioning : 16 O(d, p)17 O @ 6 Me. V An extremely complete set-up for transfer reactions measurement AGATA @backward position only ! 2 DC AGATA position Resolution~ 5 mm Distance fromtarget@ GANIL : 14 -20 cm Angular opening of cluster: 1. 5°to 2° 16 O beam @ 6 Me. V 4 104 pps 2 PPAC 2 DC MUGAST 6 Ion. Ch. Acceptance of VAMOS : +/- 6 deg MUST 2 (forward) : +/- 7. 5 deg. Annular (backward) : +/- 10 deg. Flight path ~7. 3 m 2 BTD Target thickness CD 2 : 1 mg/cm 2

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 MUGAST commissioning : 16 O(d, p)17 O @ 6 Me. V Beam intensity : ~4 104 pps No BTDs due to large straggling effect Finger in VAMOS covering 16 O and partially 17 O Yf VAMOS Focal plane Xf Mask reconstruction CATS 2 6

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 MUGAST commissioning : 16 O(d, p)17 O @ 6 Me. V Beam intensity : ~4 104 pps MUGAST No CATS due to large straggling effect Finger in VAMOS covering 16 O and partially 17 O Yf VAMOS Focal plane 90 deg. square 3 alpha contamination To. F Xf E_ DSSD MUGAST MUST 2 7

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 MUGAST commissioning : 16 O(d, p)17 O Kinematic lines for 16 O(d, p) Energy resolution : • from fit of 2 peaks : ~500 ke. V • from simulation with CD 2 1 mg/cm 2 : 500 ke. V 8

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 MUGAST commissioning : 16 O(d, p)17 O Kinematic lines for 16 O(d, p) Energy resolution : • from fit of 2 peaks : ~500 ke. V • from simulation with CD 2 1 mg/cm 2 : 500 ke. V Condition on VAMOS IC VAMOS-MUGAST relative efficiency : ~60% • a lot of pile-up event • large effect of straggling in the DC at the entrance of VAMOS 9

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 MUGAST commissioning : 16 O(d, p)17 O --> triple coincidences Relative efficiency MUGAST-AGATA: • before add-back : 5. 5% • after add-back : ~8% No cond. (d, p) reactions favorable : - Protons in backward direction : ) - No identification needed - Small background Cond. MUGAST Condition on VAMOS IC Cond. MUGAST + VAMOS E gamma (ke. V) 10

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Other transfer reactions : difficulties with (d, t) & (d, 3 He) Background free measurement needed through exclusive identification of products 14 O(d, 3 He)13 N <-- With VAMOS identification of 13 N 14 O(d, 3 He)13 N With only MUST 2 (identification of 3 He) 11

29/04/2019 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Other transfer reactions : difficulties with (d, t) & (d, 3 He) Background free measurement needed through exclusive identification of products 20 O(d, p)21 O 20 O(d, t)19 O Without spectrometer --> 15 N(d, t) 20 O(d, 3 He)19 N 15 N(d, 3 He) 20 O(d, t) A. Ramus, Ph. D thesis 12

29/04/2019 13 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Beam contamination issue : the case of 56 Ni beam at Spiral 1 1) Contamination from Co: Possible solutions (under study): à Go to fully stripped 56 Ni 28+ using a stripper foil after CIME Primary beam Target 56 Ni (12+) pps 56 Co(11+) 58 Ni 12 C 7. 3 E+04 1. 6 E+06 58 Ni Nb 4. 0 E+04 1. 7 E+06 pps Courtesy of F. Flavigny

29/04/2019 14 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Charged states from the beam : the case of 56 Ni beam at Spiral 1 1) Contamination from Co: Possible solutions (under study): à Go to fully stripped 56 Ni 28+ using a stripper foil after CIME Primary beam Target 56 Ni (12+) pps 56 Co(11+) 58 Ni 12 C 7. 3 E+04 1. 6 E+06 58 Ni Nb 4. 0 E+04 1. 7 E+06 pps 2) Charges states in VAMOS after secondary target (preliminary) Even if fully stripped 56 Ni 28+ onto a CD 2 target at 12 Me. V/nucleon: Charge state % 0. 5 mg/cm 2 % 1 mg/cm 2 % 2 mg/cm 2 28+ 17 16 15 27+ 42 41 39 26+ 31 32 34 25+ 8 9 11 Courtesy of F. Flavigny

29/04/2019 15 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Charged states from the beam : the case of 56 Ni beam at Spiral 1 1) Contamination from Co: Possible solutions (under study): à Go to fully stripped 56 Ni 28+ using a stripper foil after CIME Primary beam Target 56 Ni (12+) pps 56 Co(11+) 58 Ni 12 C 7. 3 E+04 1. 6 E+06 58 Ni Nb 4. 0 E+04 1. 7 E+06 pps 2) Charges states in VAMOS after secondary target (preliminary) Even if fully stripped 56 Ni 28+ onto a CD 2 target at 12 Me. V/nucleon: 8 56 Ni 28+ 57 Ni 28+ 56 Ni 27+ 6 4 2 57 Ni 27+ 0 56 Ni 26+ 2 57 Ni 26+ 4 56 Ni 25+ 6 7. 104 pps of unreacted beam To be stopped 8 DBrho/Brho (%) Courtesy of F. Flavigny

29/04/2019 16 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Other ideas : trifoil plastic instead of spectrometer 25 Na(d, p)26 Na @ 5 A Me. V TRIUMF ZERO DEGREE = SCINTILLATOR : tagging 25 Na(d, p)26 Na @ 10 A Me. V ZERO DEGREE = SPECTROMETER full identification Trifoil condition 10 um BC 400 plastic 40 x 40 mm 2 80% efficiency trifoil No Trifoil condition target 26 Ne(d, p)27 Ne 26 Ne+n RESULTS from TIARA/MUST 2 Nov 2007 Al (30 um) To stop fusion-evap Beam dump Adapted from W. Catford RESULTS from SHARC Aug 2009

29/04/2019 17 ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Other ideas : trifoil plastic instead of spectrometer 25 Na(d, p)26 Na @ 5 A Me. V TRIUMF ZERO DEGREE = SCINTILLATOR : tagging 25 Na(d, p)26 Na @ 10 A Me. V ZERO DEGREE = SPECTROMETER full identification With spectrometer cond Gamma spectrum TIGRESS No Trifoil condition Without spectrometer cond. Trifoil condition G. L. Wilson et al Journal of Physics: Conference Series 381 (2012) 012097 RESULTS from SHARC Aug 2009

ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Characteristics of transfer reactions with light targets • Typical intensities: > few 104/s up to 106 -7 pps. @ ISOLDE instantaneous rate 109 pps !! • Device at 0 degree -->Small scattering angles around 0°--> beam stopping and beam spot size important ! --> active finger(s) ? -->diamond detectors ? --> straggling effects ! • Performances : . Event-by-event PID: Physical separation of reaction products of interest - from the beam / isobaric beam contaminants and others : charge states / contaminants / straggling ! - from fusion-evaporation reactions with target (CH 2, CD 2, X+3 H, X+4 He, X+16 O, …). Large acceptance. Excellent angular resolution to allow kinematic reconstruction (and Doppler correction in AGATA case). A/Z resolution : - A/DA > 240 /. Z/DZ > 90 - ± a few mass and nuclear charge units should pass. Timing : useful for particle identification in some cases … @ISOLDE : slow extraction from EBIS usually required : which reference signal ? • Normalisation - Beam composition (if not pure) - Integral measurement sufficient but beam tracking devices useful (BTD limited to 105 pps)

ASSIE Marlène – Io. P Recoil spectrometer - Liverpool 29 th april 2019 Where can we found a compromise ? • Typical intensities: > few 104/s up to 106 -7 pps. @ ISOLDE instantaneous rate 109 pps !! • Device at 0 degree -->Small scattering angles around 0°--> beam stopping & beam spot size very important ! --> active finger(s) ? -->diamond detectors ? --> straggling effects ! • Performances : . Event-by-event PID: Physical separation of reaction products of interest Limited physical separation ? - from the beam / isobaric beam contaminants and others : charge states / contaminants / straggling ! - from fusion-evaporation reactions with target (CH 2, CD 2, X+3 H, X+4 He, X+16 O, …). Large acceptance. Excellent angular resolution to allow kinematic reconstruction Limited angular acceptance ? Resolution ? . A/Z resolution : Limited mass identification ? - A/DA > 240 / Z/DZ > 90 - ± a few mass and nuclear charge units should pass. Timing : useful for particle identification in some cases … @ISOLDE : slow extraction from EBIS usually required : which reference signal ? • Normalisation - Beam composition (if not pure) - Integral measurement sufficient but beam tracking devices useful (BTD limited to 105 pps)