Injector Considerations at this time Injector is not a state-of-the-art system The ring is still a moving target – length of injection straights not settled, increase to 3.6 GeV ring energy possibility was recently asked for Ring fill requirements sets charge transfer capability – initial fill time, max. allowable current fluctuations in top-off mode Emittance requirements Compact booster vs. booster in same tunnel Injector linac energy requirement – remember IR ring requires 600 MeV
NSLS II Injection R. Heese, I. Pinayev, D. Raparia, J. Rose, T.
Shaftan Injector Options Full energy linac normal or SC Compact
booster Booster in same tunnel as main ring With these factors in
mind Top-off mode for main ring Reliability Presence of 600 MeV IR
ring Cost of construction and operation Injector Considerations at
this time Injector is not a state-of-the-art system The ring is
still a moving target length of injection straights not settled,
increase to 3.6 GeV ring energy possibility was recently asked for
Ring fill requirements sets charge transfer capability initial fill
time, max. allowable current fluctuations in top-off mode Emittance
requirements Compact booster vs. booster in same tunnel Injector
linac energy requirement remember IR ring requires 600 MeV NSLS-II
injection Outline NSLS-2 Injection specifications Single-bunch and
Multi-bunch modes Top-off Choice of injector: Linac Booster
Injection bump geometry, specs and performance E-gun and low energy
linac baseline design NSLS-II Injection Specs Lifetime ~ hours (no
Harmonic Cavity) Filling pattern uniformity = 20 % bunch-bunch can
be tolerated (remember gap in bunch pattern) Average current
stability = ~ 0.5% Time between top-off cycles = 60 s 3.6 GeV, 500
mA, ~ 1560 buckets, 5/6 of them filled 1.0 nC/bucket + IR ring at
600 MeV t IbIb bunch # t QIQI t \\Nslsnt1\AccPhy\NSLS2_Injection\
Charge Transfer Requirements X-ray ring IR ringX-ray ring Energy
(GeV) Circulating Current (A) (.24 at 3.6) Circumference (m)72936
Revolution period (s) RF frequency (MHz) Circulating charge (C)
Number of buckets (Buckets filled)120 (~80)1560 (~1300) Charge per
bucket (nC) Current per bucket (mA) Lifetime (min)90180 max.
Interval of t/o cycle (min)101 Current variation over t/o
cycle10%0.5% Current variation over t/o cycle (mA) Charge variation
over t/o cycle (nC)368.5 Damping time (ms)4575 Single-bunch
injection mode Injector Rate (Hz) Time to fill ringTime to top-off
1 (Booster)36 minutes!20 s 10 (Linac)210 s (Linac)43 s0.4 Overall
time spent on top-off injection, % 33 5 3 sec!) Since booster is
above ring in the tunnel, a Lambertson septum can be of advantage,
giving DC field cancellation capability resulting in a totally
closed injection orbit bump Phase space for 6 turns COE=2mm 0.5 mm
3 mm 3i3i 6.6 mm 7.6 mm X (mrad) X (mm) Injector Linac Requirements
Minimum energy 600 MeV to serve as full energy injector for IR ring
Capable of 50 bunch train at 500 MHz of at least 500 pC each (30 m
or 100 nsec long) Requires sub-harmonic (1/6) buncher at
ring/booster frequency At least 1Hz rep rate, 3 5 Hz better for IR
ring fill High reliability requires redundancy 9 accelerating
sections giving >700 MeV capability MW Klystrons/Modulators (Hot
stand-by for section #1) Possibly 2 e-guns with switched low energy
beam transport KLYSTRON Solenoid SOLENOID SOLID STATE SWITCH MODULE
PULSE TRANSFORMER DCPS RF-SOURCE & AMPLIFIER SOLENOID PS &
IPPS TURN-KEY Solid State MODULATOR SYSTEM Slide courtesy of Mikael
Lindholm, ScandiNova Benefits: Greatly Improves Reliability,
Maintainability Smaller footprint Variable pulse width can be used
to increase rep rate within average power limits: 5 s at 50 Hz,.75
s at 300 Hz. SLED vs. FEL performance S-Band Structures Parameter:
mode2 /3 frequency GHz length 5.2 m no. of cells including absorber
shunt imp.51 M /m Q14000 filling time0.74 s Slide courtesy of ACCEL
130k EU each ASP booster (Danfysik) Energy: 0.1 3 GeV Rep. Rate: 1
Hz Circumference: 130 m RF frequency: 500 MHz Emittance: 30 nm rad
Radiation loss: 743 keV/turn Beam current: >5 mA Magnet power:
240 kW Booster cost = 100 MeV linac+3 GeV booster+2 transport
lines+installation and commissioning=21 M$ 4.5m 4.5m 20m -0.5m
0.5m32.7m xx yy Booster map Electron gun600MeV linac Booster SR
injection Compact injector with IR ring (Stylized) Compact Booster
Lattice design Note: Compact booster is larger than NSLS X-ray ring
24 TME cells (NSLS-I booster) Two 8 m long straight sections 24
combined function magnets (L=2m, =13.85 , n=17) 4 Dispersion
suppressors 38 quadrupoles (5 families) Sextupoles (2 families) are
integrated into dipoles and quads DA>30 mm Chromaticity: -28.6;
-8.6 Tunes 12.16; 4.36 Momentum compaction Regular cell Dispersion
suppressor 32-fold FODO 32-cell 3.5 GeV BMPM output Synchrotron
integrals: I1 I2 I3 (C)I4 I5 I6X I6Y I E E E E E E E E+00 Global
machine parameters (two beams), and local parameters at interaction
point: Q_x = beta_x* = [m] etax* = [m] Q_y = beta_y* = [m] etay* =
[m] alpha = E-02 circumf. = [m] t_0 = E-06 [sec/turn] (C)J_x = J_y
= (C)J_e = dJ_x/(dE/E) = dE/E = df_RF = E+06 [Hz] Beam parameters
and luminosities: (D)energy = [GeV] (C)coupling = (C)delta_Q = NaN
U0 = [MeV/turn] sig_E = E-04 dE/E B*rho = [Tm] tau_x = E-03 [sec]
tau_y = E-02 [sec] tau_E = E-03 [sec] E_x_0 = pi [micro-m] (C)E_x_c
= pi [micro-m] sig_x_0 = [mm] sig_x_c = [mm] sig_x_T = [mm] sig_y_0
= [mm] sig_y_c = [mm] sig_y_T = [mm] L_x = Infinity [1/cm**2 sec]
n_x = E+11 per beam (C)I_x = E-02 [A] / bunch L_y = NaN [1/cm**2
sec] n_y = per beam I_y = [A] / bunch k_bunch = 1 tau_pol = [min]
tau_brems = [min] n_int = 2 pol_infinit. = percent RF related
parameters (for a total of 1 cavities): f_RF/f_0 = 1560 (D)volt._RF
= [MV] f_RF = [MHz] phi = [degrees] Q_s = E-02 f_synchr. = [kHz]
(C)sig_buck. = E-04 sig_s = [mm] (C) tau_Q = E-04 [min] shunt imp.
= [MOhm/m] L_cavity = E-03 [m] t_fill = [microsec] (C)power =
Infinity [MW] K_hm = [V/pC] (C)beta_RF = (C)psi = [degrees]
(C)bucket = cell 3.5 GeV "MAD" Version: 8.51/15 Run: 19/04/ 64-fold
FODO 64-cell 3.5 GeV BMPM output page Synchrotron integrals: I1 I2
I3 (C)I4 I5 I6X I6Y I E E E E E E E E+00 Global machine parameters
(two beams), and local parameters at interaction point: Q_x =
beta_x* = [m] etax* = [m] Q_y = beta_y* = [m] etay* = [m] alpha =
E-02 circumf. = [m] t_0 = E-06 [sec/turn] (C)J_x = J_y = (C)J_e =
dJ_x/(dE/E) = dE/E = df_RF = E+06 [Hz] Beam parameters and
luminosities: (D)energy = [GeV] (C)coupling = (C)delta_Q = NaN U0 =
[MeV/turn] sig_E = E-04 dE/E B*rho = [Tm] tau_x = E-02 [sec] tau_y
= E-02 [sec] tau_E = E-03 [sec] E_x_0 = pi [micro-m] (C)E_x_c = pi
[micro-m] E_y_c = pi [micro-m] sig_x_0 = [mm] sig_x_c = [mm]
sig_x_T = [mm] sig_y_0 = [mm] sig_y_c = [mm] sig_y_T = [mm] L_x =
Infinity [1/cm**2 sec] n_x = E+10 per beam (C)I_x = E-03 [A] /
bunch L_y = NaN [1/cm**2 sec] n_y = per beam I_y = [A] / bunch
k_bunch = 1 tau_pol = [min] tau_brems = [min] n_int = 2
pol_infinit. = percent RF related parameters (for a total of 1
cavities): f_RF/f_0 = 1560 (D)volt._RF = [MV] f_RF = [MHz] phi =
[degrees] Q_s = E-02 f_synchr. = [kHz] (C)sig_buck. = E-04 sig_s =
[mm] (C) tau_Q = E-05 [min] shunt imp. = [MOhm/m] L_cavity = E-03
[m] t_fill = [microsec] (C)power = Infinity [MW] K_hm = [V/pC]
(C)beta_RF = (C)psi = [degrees] (C)bucket = cell 3.5 GeV "MAD"
Version: 8.51/15 Run: 19/04/ NSLS-Booster-like lattice with 64
cells BMPM output Synchrotron integrals: I1 I2 I3 (C)I4 I5 I6X I6Y
I E E E E E E E E+00 Global machine parameters (two beams), and
local parameters at interaction point: Q_x = beta_x* = [m] etax* =
[m] Q_y = beta_y* = [m] etay* = [m] alpha = E-03 circumf. = [m] t_0
= E-06 [sec/turn] (C)J_x = J_y = (C)J_e = dJ_x/(dE/E) = dE/E = E-02
df_RF = [Hz] Beam parameters and luminosities: (D)energy = [GeV]
(C)coupling = (C)delta_Q = E-02 U0 = [MeV/turn] sig_E = E-03 dE/E
B*rho = [Tm] tau_x = E-02 [sec] tau_y = E-02 [sec] tau_E = E-02
[sec] E_x_0 = E-02 pi [micro-m] (C)E_x_c = E-03 pi [micro-m] E_y_c
= E-03 pi [micro-m] sig_x_0 = [mm] sig_x_c = [mm] sig_x_T = [mm]
sig_y_0 = [mm] sig_y_c = [mm] sig_y_T = [mm] L_x = E+28 [1/cm**2
sec] n_x = E+10 per beam (C)I_x = E-03 [A] / bunch L_y = E+28
[1/cm**2 sec] n_y = E+10 per beam I_y = E-03 [A] / bunch k_bunch =
1 tau_pol = [min] tau_brems = [min] n_int = 2 pol_infinit. =
percent RF related parameters (for a total of 1 cavities): f_RF/f_0
= 1260 (D)volt._RF = [MV] f_RF = [MHz] phi = [degrees] Q_s = E-02
f_synchr. = [kHz] (C)sig_buck. = E-03 sig_s = [mm] (C) tau_Q = E+08
[min] shunt imp. = [MOhm/m] L_cavity = E-03 [m] t_fill = [microsec]
(C)power = Infinity [MW] K_hm = [V/pC] (C)beta_RF = (C)psi =
[degrees] (C)bucket = NSLS-Booster-like lattice with 64 cells "MAD"
Version: 8.51/15 Run: 19/04/ NSLS-booster-like with 64 cells Some
features of modified NSLS booster Addition of defocusing
quadrupoles to be able to cover an area in tune space H-magnets
with fields below 0.8 T Magnets powered in many small groups 1 Hz
repetition rate suffices with pulse train injection Extraction
kicker 100 nsec flat-top (not a problem) Extraction orbit bumps
again can be in series NSLS II Tunnel Work for immediate future
Optimize booster (tracking, RF system, magnet power supply
configurations, orbit control, ramping trims, etc.) for costing and
engineering Address the fear over booster fringing fields effects
on main ring Flesh out transport lines and get more definite specs
for injection/extraction hardware Showstoppers!!!! Are there any?
Conclusion Injection of NSLS-II can be done in several ways, we
chose in-tunnel booster with full energy injector for IR ring for
reasons of cost, reliability and efficiency of operation.
