AGFA – the Argonne Gas-Filled Analyzer

Presentation at the 2014 ATLAS User’s MeetingMay 15-16, 2014

Birger B. Back

Birger B. Back ATLAS User's Meeting, May 15-16, 20142

Our role:

ATLAS Strategic Plan, November 2009

Effective long-term operation of the accelerator

Development of new accelerator capabilities to enable new high priority research opportunities

Effective support of the experimental program

Development of new experimental capabilities to pursue new high-priority research opportunities

Nurturing the scientific and technical base of the low-energy research community and helping to develop the high-quality workforce for future initiatives.

User advise and support needed for the instrument development plan

AGFA and the ATLAS intensity upgrade:intense beams – maximize physics reach

AGFA: High efficiency separation of reaction products– Study exotic nuclei produced with very small cross sections

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Argonne Gas-filled Fragment Analyzer-AGFACollaboration

B.B. Back, R.V.F. Janssens, W.F. Henning, T.L. Khoo, J.A. Nolen, D.H. Potterveld,G. Savard, D. Seweryniak, Argonne National Laboratory M. Paul, Hebrew University, Jerusalem, Israel

P. Chowdhury, C.J. Lister, University of Massachusetts Lowell

W.B. Walters, University of Maryland

P.J. Woods, University of Edinburgh

K. Gregorich, Lawrence Berkeley National Laboratory

W. Loveland, Oregon State University

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Unique design (Potterveld)

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Three functions:• Vertical focussing• Horizontal focussing• Horizontal bend

Short length and large acceptance achieved with two magnetic elements• Q1: vertical focusing• D1: 38o bend and horizontal focusing

Vertical Horizontal

Dm

Qv

48Ca+208Pb

AGFA – FMA – Gammasphere – Gretina in Area 4

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Purpose: High efficiency separation

– Gammasphere at target position

– Evaporation residues• Superheavy nuclear

structure and fission barriers

• ~100Sn region• Heavy proton emitters• Other uses

– Deep-inelastic products• N-rich nuclei e.g. N~126

With Digital Gammasphere this is a unique capability

AGFA: 50-95% Efficiency

FMA: Less efficiency, m/q measurement

Birger B. Back ATLAS User's Meeting, May 15-16, 2014

Integration with Gammasphere

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Dipole magnet Quadrupole magnet Gammasphere

AGFA Support stand

Gammasphere support stand (schematic)

Target to quad front: 80cm

Heavy element reaction

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Figure 15: Left: X-Y image of 254No recoils at the focal plane. The grey area corresponds to that a covered by a 64x64mm2 DSSD. Right: Projections onto the horizontal (lower panel) and vertical (upper panel) where the grey area indicates the extent of the DSSD.

Reaction Beam energy Erecoil(initial) Qrecoil(initial) Target thickness

208Pb(48Ca,2n)254No MeV 37 ±2 MeV 19±2 0.5 mg/cm2 Beam profile x y (dx/dz) (dy/dz) 2.1 mm 0.85 mm 0.036 0.036 Magnetic rigidity 4He gas press. Target-Q1 dst 2.09 Tm 1 Torr 80 cm

Distribution at focal plane 64x64 mm2 DSSD

200 MeV

48Ca+208Pb → 254No+2n

Efficiency: 71%

“100Sn reaction”

Birger B. Back ATLAS User's Meeting, May 15-16, 2014 9

Figure 16: Same as Fig. 15, but for the reaction 182MeV 54Fe+54Fe→106Te+2n with 10 Torr He gas in AGFA.Reaction Beam energy Erecoil(initial) Qrecoil(initial) Target

thickness 54Fe(54Fe,2n)106Te MeV 89.4 ±2 MeV 25±2 1.1 mg/cm2 Beam profile x y (dx/dz) (dy/dz) 2.1 mm 0.85 mm 0.018 0.0058 Magnetic rigidity 4He gas press. Target-Q1 dst 0.86 Tm 10 Torr 80 cm

Distribution at focal plane 64x64 mm2 DSSD

182 MeV

54Fe+54Fe → 106Te+2n

Efficiency: 95%

AGFA relative to existing separators

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Separator and Location

Config. Solid angle (msr)

Bend Angle

Max. B-rho ( Tm )

Length (m)

Target Dist. (cm)

AGFA @ ATLAS QvDm 22.5 38o 2.5 4.2 80 AGFA @ ATLAS QvDm >40 38o 2.5 3.7 40 BGS @ LBNL QvDhD 45 70o 2.5 4.6 35 TASCA @ GSI DQhQv 13 30o 2.4 3.5 15 RITU @ Jyväskylä QvDQhQv 10 25o 2.2 4.7 40 Garis II@ Riken DQhQvD 20 45o 2.4 5.1 <40 GFS @ Dubna DQhQv 10 23o 3.1 4.3 <40

Beam suppression for 106Te recoils

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Figure 17: Focal plane distributions of 106Te recoils (blue) and beam particles (red) in AGFA (left panel) and RITU (right panel) for a 10 Torr He gas pressure in both separators.

Reaction: 54Fe(54Fe,2n)106Te, 182 MeV

AGFA technical specifications

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Parameter Required Value Configuration QvDm Maximum bending power, B 2.5 Tesla-m Maximum field at Qv pole tip 1.24 Tesla Maximum Qv power consumption 90 kW Maximum field at Dm pole tip 1.70 Tesla Maximum Dm power consumption 100 kW Bend angle 38 degrees Target to Qv distance, dtQ 40 cm 80 cm Solid angle, 44 msr 22 msr Target to focal plane distance 3.7 m 4.3 m

Budget

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Component(s) Cost (k$) Dipole magnet incl. power supply $500k Quadrupole magnet incl. power supply $200k Vacuum pumps $125k Support stand $100k Beamline $50k Target chamber wheel $50k Dipole vacuum chamber $50k Detector and focal plane vacuum chambers $50k Design – engineering support $100k Vacuum gauges, valves, etc. $75k Utilities $50k Total (no contingency) $1350k Contingency (30%) $405k Total w. contingency $1755k

Status and schedule

July 2013: Tentative DOE approval – request Project Management Plan (PMP)

Sept 2013: Project Management Plan submitted to DOE for review

Nov 2013 – now: Modifications to Project Management Plan

Aug 2014: AGFA review

Oct 2014: Start project

Oct 2016: Start experimental program

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Thank you

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