1. JLEIC ion source: specifications, design, and R&D prospects
A. Sy
October 5, 2016
A. Sy - JLEIC Fall 2016 Collaboration Meeting

2. JLEIC ion complex
JLEIC figure 8 preserves initial polarization – Need max polarization from ion source
ion sources
ion linac
Booster
Collider ring
BB cooler
DC cooler
[Jan Design Summary, arXiv: ]
A. Sy - JLEIC Fall 2016 Collaboration Meeting

3. Polarized ion formation
How do we get polarized ions?
Polarize electrons and transfer polarization to unpolarized atomic nucleus
Resonant Charge Exchange
Optical Pumping
H0↑ + D− → H−↑ + D0
-Thermal atomic beam polarized in inhomogeneous magnetic field
[Zelenski et al., Hyperfine Interactions (2000) 127:475.]
A. Sy - JLEIC Fall 2016 Collaboration Meeting

4. Existing polarized ion sources (1)
ABPIS: Atomic beam polarized ion source (INR)
Resonant charge-exchange plasma ionizer
Polarized H-: 3.8 mA measured
Max measured polarization 91%
Polarized D- expected with similar performance
3He, Li should be possible with source modification
Nearly resonant charge exchange processes can produce polarized H-, D-, 3He+/++, Li+, T+, T-
[Belov et al., Rev. Sci. Instrum. 67 (3) (1996)]
[Belov et al., Rev. Sci. Instrum. 77, 03A522 (2006)]
A. Sy - JLEIC Fall 2016 Collaboration Meeting

5. Existing polarized ion sources (2)
OPPIS: Optically-pumped polarized ion source (RHIC)
Upgraded from ECR to atomic beam injection
Polarized H-: 4 mA measured
Max measured polarization 85%
Polarized D- possible only up to ~56% polarization; needs second optical pump stage for closer to 70% polarization
[Zelenski et al., Rev. Sci. Instrum. 87, 02B705 (2016)]
A. Sy - JLEIC Fall 2016 Collaboration Meeting

6. JLEIC polarized ion source
How close are state-of-the-art devices to meeting JLEIC requirements?
(units)
Desired value
ABPIS+
OPPIS*
Charge status H-
Pulse current mA 2
3.8
4 (0.7)
Pulse length ms
0.5
0.17
(0.3)
Charge per pulse μC 1
0.65
Protons per pulse
1012
6.24
4.03
Polarization %
100 91 85
+[Belov et al., Rev. Sci. Instrum. 77, 03A ]
*[Zelenski et al., Rev. Sci. Instrum. 87, 02B705 (2016)]
-Linac parameters in parentheses; 85% polarization at 200 MeV
A. Sy - JLEIC Fall 2016 Collaboration Meeting

7. Unpolarized heavy ion sources (1)
EBIS: Electron beam ion source
Charge breeding requires high intensity electron gun, external ion sources
Narrow charge state distribution, intense pulses
Typically ~mA currents for single charge state
12-14% ions per pulse are ions of interest
[Alessi et al., Rev. Sci. Instrum. 81, 02A509 (2010)]
A. Sy - JLEIC Fall 2016 Collaboration Meeting

8. Unpolarized heavy ion sources (2)
ECR: Electron cyclotron resonance source
RF discharge in magnetic mirror field at electron cyclotron frequency breeds high charge state ions
Long ionization times result in long pulse lengths
Higher RF frequency, B field (50 GHz) for plasma densities that can support short ionization times
[S. Gammino, arXiv: ]
[J. G. Alessi, LINAC2004 (MO202)]
A. Sy - JLEIC Fall 2016 Collaboration Meeting

9. JLEIC unpolarized ion source
Source performance is very specific to charge state of interest
(units)
Desired value
EBIS+
ECR*
Charge status
Pb30+
Au32+
Pb27+
Pulse current mA
1.3
1.7
~0.5
Pulse length ms
0.01
0.02
~0.2
Charge per pulse μC
0.075
0.1
Ions per pulse
1010 1
~0.23
+[Beebe et al., AIP Conf. Proc. 1640, 5 (2015)]
*[Sortais et al., Rev. Sci. Instrum. 75, 1610 (2004)]
A. Sy - JLEIC Fall 2016 Collaboration Meeting

10. Outlook
Several options for both polarized and unpolarized ion sources for JLEIC
ABPIS promising for polarized source option
EBIS promising for unpolarized source option
See next talk for possible polarized ion source R&D
A. Sy - JLEIC Fall 2016 Collaboration Meeting