Spectrometer Workshop 10/3 – 11/3 Lund University

March 10-11, 2011 | Spectrometer at HIE- ISOLDE, Workshop, Lund | Thorsten Kröll | IKP, TUD | 4 Request from LoIs 35 LoIs for HIE-ISOLDE have been submitted so far 15 say that they will profit from spectrometer or separator Mostly to identify beam-like particles Only 1 explicitly mentions the use as spectrometer (reactions with light particles) 12 of these LoIs request the MINIBALL + CD or T-REX set-up Other set-ups: 1 LoI with GASPARD 1 LoI with ACTAR 1 LoI for identification of fission fragments HELIOS / PARIS … no spectrometer mentioned … impact on mechanical design?

March 10-11, 2011 | Spectrometer at HIE- ISOLDE, Workshop, Lund | Thorsten Kröll | IKP, TUD | 5 Physics cases Reaction types: Coulomb excitation Direct reactions with light targets (up to 16 O) Transfer induced fission Not proposed so far: Transfer reactions with heavy targets Deep inelastic reactions Fusion-evaporation compound reactions … Beams: Full range of isotopes available at HIE-ISOLDE (Li to Ra)

March 10-11, 2011 | Spectrometer at HIE- ISOLDE, Workshop, Lund | Thorsten Kröll | IKP, TUD | 6 Transfer reactions with light targets Energy: MeV/u Intensities: > 10 5 /s Small scattering angles around 0° Event-by-event PID - Identification of heavy transfer product - Reactions of beam contaminants - Fusion-evaration reactions with target / carrier (CH 2, CD 2, Ti+ 3 H, 9,10 Be, X+ 3 He, X+ 4 He, X+ 16 O, …) Also needed for analysis: - Beam composition for normalisation - Integral measurement sufficient

What would an ideal zero-degree device achieve? identification of reaction products physical separation of reaction products of interest, from the beam physical separation of reaction products of interest, from fusion-evap physical separation of isobaric beams or other beam contaminants large enough angular acceptance to pick up sequential decay products excellent angular resolution to allow kinematic reconstruction – missing-p to avoid compromising the placement of gamma-ray detectors to be consistent with good coverage by other detectors around target to have sufficient flight path to allow for the use of TOF methods to be as transportable as the rest of the set-up, to optimise exploitation What are we prepared to lose? What is the compromise? accept limited mass identification of reaction products? forego physical separation? tolerate limited angular acceptance? angular resolution? relax the requirement of portability? Wilton Catford, University of Surrey, UK – HIE-Isolde Spectrometer Workshop, Lund, March 2011

24 Ne(d,p  ) N=16 replaces broken N=20 W.N. Catford et al., Eur. Phys. J. A25, Suppl. 1, 245 (2005). Schematic of the TIARA setup. A beam of 10 5 pps of 24 Ne at 10.5A MeV was provided from SPIRAL, limited to 8  mm.mrad to give a beam spot size of mm. The target was 1.0 mg/cm 2 of (CD 2 ) n plastic. The TIARA array covered 90% of 4  with active silicon. OUR EXPERIMENT TO STUDY 25 Ne d 3/2

24 Ne (d,p) 25 Ne Requiring Vamos (Focal Plane Plastic) Without Vamos Requirement BEAM (d,t) tritons Knock-on carbon elastics (saturation) (90 degrees) ~ 10 A.MeV

Summary: Prepare a Document by end Next Workshop in Madrid Feb.-March 2012 to discuss the document and prepare a strategy TimeLine: HIE-ISOLDE Physics 2014 too early for spectrometer. We aim for the upgrade and install Organization: Coordinators: Olof Tengblad Wilton Catford Joakim Cederkäll Unique problem at HIE-ISOLDE: the instantaneous intensity  need to improve on the EBIS extraction For which there is in preparation a NupNet project (P. Delahaye we do not know if this happened? HIE-ISOLDE Spectrometer Working Group workshop March 2011 LUND

WG1 Physic case: Reaction types: transfer, Coulomb excitation, deep inelastic, fusion evaporation Beam and target combinations Convener Thomas Kröll Joakim Cederkäll Benjamin Kay David Jenkins Janne Pakarinen Tuomas Grahn Ricardo Raabe WG2 Detectors Focal plane detectors, tracking for gamma corrections (doppler broadening), particle ID Pluncher Tiara, Sharc, Helios, Gaspar…. Second hand!? Convener Dennis Mu ̈ cher Dave Joss Nigel Warr Emmanuel Clement Yorik Blumenfeld Working Groups

WG3 Ion Optics Simulations Ray Tracing: Vamos, Prisma Mass Separator: EMMA, Mara, Ritu Question: Can ONE design meet all requirements from 9Li < A < 226Rn Beam spot size and entrance angle from ISOLDE Beam extraction from EBIS we need 100 ns separation and 0.5 ns start signal for ToF Flexibillity to work with MiniBall, T-rex, Heliso etc.. Convener Juha Uusitalo Jan Sarén Gry Tveten Matteo Pasini Maurycy Rejmund International Collaborators: Barry Davids (EMMA – Triumf) ISOLDE: Erwin Siesling (Building) Thierry Stora (Targets)

Some issues identified 1. Counting rate requirements: since a typical average beam intensity requirement is 10E5 pps, the essential consideration is whether the charge-breeder release must definitely give a compression of 10E4 effectively. If this is true, then It means the direct beam must be physically isolated from reaction products It means that with rebunching to have pulses every 100 ns then there will be on average 100 beam particles per pulse 2. How should the beam be stopped at the focal plane? If the activity is long-lived then it could be a problem, even at 105 pps. In the EMMA solution the main charge states are distributed across a wide range in the focal plane (much more than the 5 mm between adjacent masses), and other charges are dumped somewhere. In VAMOS, for Sn, of order 9 charge states are transmitted to the focal plane, but are not separated physically from the reaction products. 3. Does the increased number of charge states transmitted by VAMOS compensate in any sense for the lack of physical separation? 4. In the EMMA solution, what are the full consequences of the limitations in energy (to just a few MeV/u) and consequent need for degrader foils? 5. Is the angular acceptance of the EMMA solution, of +/- 4 degrees, sufficient? If so, then is the design or performance of the VAMOS solution significantly simplified or enhanced by this restriction in angle? 6. Does the existence of charge state ambiguities in an way reduce the attractiveness of the EMMA solution? 7. Is the access around the target for EMMA or VAMOS sufficient for the desired arrays around the target? Would a VAMOS with reduced angular acceptance have significantly more room? Is the proposed arrangement for EMMA acceptable, even with the degrader foil in place? 8. Is the required size of the beam spot achievable and in the plan? 9. Are both solutions equally good at effectively removing isobaric or other beam contaminants from the data? 10. There is no number 10.

HIE-ISOLDE Separator Working groups Coordinator: Olof Tengblad with Wilton Catford and Joakim Cederkall 1) Report from Workshop to the HIE-Isolde Physics coordination group sometime April ) Prepare a document by end ) Next Workshop Madrid Feb.-March 2012 to discuss the document and make a strategy 4) Time line: HIE-ISOLDE Physics 2014 too early for spectrometer, aim for the upgrade and install WG1 Physic cases: Thorsten Kröll Benjamin Kay, David Jenkins, Janne Pakarinen, Thomas Grahn, Ricardo Raabe, Joakim Cederkall WG2 Detectors: Dennis Muecher Dave Joss, Nigel Warr, Emmanuel Clement, Yorick Blumenfeld WG3 Ion Optics Simulations: Juha Uusitalo Jan Sarén, Gry Tveten, Matteo Pasini, Maurycy Rejmund

March 10-11, 2011 | Spectrometer at HIE- ISOLDE, Workshop, Lund | Thorsten Kröll | IKP, TUD | 16 Specs for a spectrometer/separator A device at 0° is sufficient for most LoIs so far A/Z-Resolution (covering also heavy beams) - A/  A > Z/  Z > 90 … nuclear charges! - ± a few mass and nuclear charge units should pass - atomic charge states? Energy / momentum; p/  p or E/  E ??? Intensities: 10 5 /s for heavy beams means 10 9 /s instantaneous rate!!! Timing: Usually slow extraction from EBIS required  useful timing signals from HIE-ISOLDE for TOF ???