HRS Workshop 2014-07-11 [1]

Thomas Baumann, NSCL

Pre-conceptual design of the next

High Rigidity Spectrometer

Outline:

• Introduction

• Design requirements

• Similar other projects

• Design concept

• Design choices

HRS Workshop 2014-07-11 [2]

Introduction

The current Sweeper Magnet and S800 Spectrograph are used in a

large variety of experiments:

• elastic and inelastic scattering experiments

• charge exchange and knock-out reactions

• measurement of neutron unbound states

• combination with auxiliary detectors, for e.g. γ-ray spectroscopy

The proposed High Rigidity Spectrometer should combine these

functions and will be a centerpiece of the fast beam program at

FRIB.

HRS Workshop 2014-07-11 [3]

Sweeper & S800 Spectrograph

• Superconducting,

high-field, large-gap

dipole

• max. 4 Tm bending

power, 4 T field.

• 14 cm vertical gap

• 15% momentum

acceptance.

• Superconducting large-

acceptance, high-

resolution spectrograph

• 4 Tm maximum rigidity

• 120 mrad by 180 mrad

acceptance

• 6% momentum

acceptance.

HRS Workshop 2014-07-11 [4]

Other projects: SAMURAI, GLAD, SHARAQ

Gastineau et al.,

IEEE Trans. Appl. Supercond 18 (2008) 407–410

Sato et al.,

IEEE Trans. Appl. Supercond 23 (2013) 4500308

→Hideaki Otsu

Uesaka et al., J. of Phys. 312 (2011) 052028

→Georg Berg

HRS Workshop 2014-07-11 [5]

New High Rigidity Spectrometer: requirements

Need a spectrometer that is matched to FRIB fast beam parameters:

• at least 7 Tm beam rigidity

• large acceptance for charged particles (about 20 msr, 10% in

momentum)

• medium momentum resolution of better than 1/1000

• work with auxiliary detector

systems:

• GRETINA

• MoNA-LISA, etc.

• large acceptance for neutrons:

±8° (100% acceptance for 40Al

2-MeV decay at 150 MeV/u)

HRS Workshop 2014-07-11 [6]

New High Rigidity Spectrometer: concept

• Combination of 2 dipoles

and focusing quadrupoles

• 1st dipole is the sweeper.

Deflection angle and gap

size determines neutron

acceptance.

• Quadrupole bores

determine acceptance of

charged particles.

• 2nd dipole deflection angle

can be chosen to achieve

desired resolution.

sweeper

dipole

quad-triplet

spectrometer

dipole

charged particle detectors

neutron detector

auxiliary

detectors

HRS Workshop 2014-07-11 [7]

Proposed combination

of Sweeper magnet

with S800

Spectrograph (from

Sweeper MRI

proposal, 1997).

Sweeper/Spectrometer: not a new idea

HRS Workshop 2014-07-11 [8]

New High Rigidity Spectrometer: 2.1 T sweeper

HRS Workshop 2014-07-11 [9]

New High Rigidity Spectrometer: 2.1 T sweeper

• Consists of one dipole sweeper magnet, two quadrupole triplets, and two

dipole magnets.

• Maximum magnetic rigidity: 8 Tm.

• Acceptance: 80 mrad by 80 mrad (charged particles), 10% dp/p, ±6° (vertical,

neutrons)

• Image after sweeper; Resolution: 5000; dispersion at focal plane: 7 cm/%

• Sweeper: 30° bending angle, 2.1 T max. field, 60 cm gap. Possibly H-type

magnet.

• Main dipoles: 2×30° bending angle,

2.1 T max. field, 12 cm gap.

• Quadrupoles: based on FSQ7/8

design for FRIB separator,

~50 cm max. bore (without

multipoles).

HRS Workshop 2014-07-11 [10]

New High Rigidity Spectrometer: 2.1 T sweeper

Zmin= 43.00 m Zmax= 70.00 m Xmax= 50.0 cm Ymax= 50.0 cm Ap * 1.00 Thu Jun 05 11:32:33 2014

D1

20.941

D1

20.941

2QA

19.000

2QB

-28.646

2QC

24.169

3QA

11.472

3QB

-26.334

3QC

17.032

-20.941

-20.941

F0

D1F

F1

S1

S2

F2

D2

F3

F4

F5

F6

F7

F8

'HRS Preconcept May 2014 #25'

HRS Workshop 2014-07-11 [11]

New High Rigidity Spectrometer: 2.1 T sweeper

Zmin= 43.00 m Zmax= 70.00 m Xmax= 50.0 cm Ymax= 50.0 cm Ap * 1.00 Thu Jul 10 14:53:24 2014

D1

20.941

D1

20.941

4TA

16.300

4TB

-18.757

5TA

23.718

5TB

-23.604

6TA

-20.554

6TB

22.386

7TA

-14.272

7TB

8.208

-20.941

-20.941

F0

D1F

F1

S1

F2

S2

F3

D2

F4

F5

F6

F7

'HRS Preconcept May 2014 #27'

HRS Workshop 2014-07-11 [12]

New High Rigidity Spectrometer: 2.1 T sweeper

HRS Workshop 2014-07-11 [13]

Accommodating light charged particles

Shown are the flight paths of

two cones of reaction

products with a rigidity ratio

of 2:1.

A narrow return yoke design

might be able to

accommodate these particles.

HRS Workshop 2014-07-11 [14]

New High Rigidity Spectrometer: simple alternative

• Consists of one dipole sweeper magnet, one quadrupole triplet, and one dipole

magnet.

• Maximum magnetic rigidity: 7 Tm.

• Acceptance: 90 mrad by 90 mrad (charged particles), 10% dp/p, ±8° (neutrons,

vertical)

• Resolution: 5500; dispersion at focal plane: 5.5 cm/%

• Sweeper: 35° bending angle,

2.2 T max. field, 44 cm gap.

• Main dipole: 60° bending angle,

2.1 T max. field, 40 cm gap.

• Quadrupoles: 42 cm max. bore.

HRS Workshop 2014-07-11 [15]

New High Rigidity Spectrometer: simple alternative

Zmin= 0.00 m Zmax= 16.00 m Xmax= 50.0 cm Ymax= 50.0 cm Ap * 1.00 Sat Jun 14 17:09:57 2014

D1

21.565

2TA

19.000

2TB

-16.582

2TC

4.908

20.948

20.948

TG

F1

S1

D2

F2

F2

F3

F4

F5

F6

'hrs preconcept 01-Oct-13'

HRS Workshop 2014-07-11 [16]

New High Rigidity Spectrometer: 6 T sweeper

• Maximum magnetic

rigidity: 8 Tm.

• Acceptance:

120 mrad by 180 mrad

(charged particles),

10% dp/p, ±8° (neutrons)

• Resolution: 3200; dispersion

at focal plane: 6 cm/%

• Sweeper: 45° bending angle,

6 T max. field, 57 cm gap.

• Main dipole: 45° bending

angle, 2.1 T max. field, 24

cm gap.

• Quadrupoles: 70 cm max.

bore.

HRS Workshop 2014-07-11 [17]

New High Rigidity Spectrometer: 6 T sweeper

Zmin= 0.00 m Zmax= 25.00 m Xmax= 50.0 cm Ymax= 50.0 cm Ap * 1.00 Fri May 02 13:50:53 2014

D1

59.831

D1

59.831

2QA

-12.261

2QB

22.100

2QC

-13.600

3QA

-10.124

3QB

13.370

3QC

-6.692

20.941

20.941

TG

D1F

F1

S1

S2

F2

D2

F3

F4

F5

F6

F7

F8

F9

'hrs preconcept 01-Oct-13'

HRS Workshop 2014-07-11 [18]

Possible location of HRS

HRS Workshop 2014-07-11 [19]

Thanks for ideas and feedback from:

Daniel Bazin, Georg Bollen, Earle Burkhardt, Shailendra Chouhan,

Marc Hausmann, Don Lawton, Brad Sherrill, Michael Thoennessen,

Remco Zegers, Al Zeller.

Acknowledgments