Voltage uniformity across a photocathode
!
!
TIME-STEP            0.05E-12
RESOLUTION-TIME      1.0E-12
END-TIME             25.0E-9
NUMBER-PRINTS        5
EXECUTE-CYCLES       ALL
ECHO                 YES
GRIDS                NO
MAX-POINTS           4001
DETAIL-PRINTS  FULL
!
!
!   This circuit uses 2, idealized 50-Ω waveforms to couple to each side of a 25-Ω photocathode.
!
!   October 2019
!
! We have a main branch with a 50-Ω matched driver feeding a long 50-Ω TL as time isolation.
! The 50-Ω cable feeds a 25-Ω photocathode piece that then feeds another identical 50-Ω TL.
! There is a end branch at the load end that has identical voltage waveform as the initial 
! voltage source. It is critical that we examine the voltage uniformity across the PC. Note, 
! the mismatch will be symmetric so we really only need to look i detal at ½ of the PC TL.
! --- I need to calculate the exact impedance based on the details of the geometry.
! 
! With a 50-ns cable we will have a TL resolution of 0.5 ns (1%) and a time step 
! that is 1/10 of the TL resolution. Decreasing the Time Step below 1/10 TL Res time makes
! no difference.
! Decreasing the TL resolution time below 0.5 ns dramatically increases run time in V4.
! e.g. 0.5/0.025 - 4.5 sec ; 0.25/0.025 - 91 sec
! above this point time scales linearly with time step and TL res
! For a 50-ns cable the TLres increases node count dramatically
!

! Main Branch - Branch #1

BRANCH

!
!    *********   voltage driver   *************************
!
! I created a voltage table of the desired waveform. This was generated in KG and pasted here.
!

VOLtsource TABle  50.0  0.0
2000.0          0.0
0.0000             0.0000
2.0000e-11   -0.078813
4.0000e-11   -0.14866
6.0000e-11   -0.21086
8.0000e-11   -0.26648
1.0000e-10   -0.31642
1.2000e-10   -0.36143
1.4000e-10   -0.40214
1.6000e-10   -0.43907
1.8000e-10   -0.47269
2.0000e-10   -0.50337
2.2000e-10   -0.53145
2.4000e-10   -0.55721
2.6000e-10   -0.58091
2.8000e-10   -0.60275
3.0000e-10   -0.62293
3.2000e-10   -0.64161
3.4000e-10   -0.65893
3.6000e-10   -0.67503
3.8000e-10   -0.69002
4.0000e-10   -0.70399
4.2000e-10   -0.71704
4.4000e-10   -0.72924
4.6000e-10   -0.74067
4.8000e-10   -0.75139
5.0000e-10   -0.76146
5.2000e-10   -0.77094
5.4000e-10   -0.77985
5.6000e-10   -0.78826
5.8000e-10   -0.79620
6.0000e-10   -0.80369
6.2000e-10   -0.81078
6.4000e-10   -0.81750
6.6000e-10   -0.82386
6.8000e-10   -0.82989
7.0000e-10   -0.83562
7.2000e-10   -0.84107
7.4000e-10   -0.84625
7.6000e-10   -0.85118
7.8000e-10   -0.85588
8.0000e-10   -0.86035
8.2000e-10   -0.86463
8.4000e-10   -0.86871
8.6000e-10   -0.87260
8.8000e-10   -0.87633
9.0000e-10   -0.87990
9.2000e-10   -0.88331
9.4000e-10   -0.88658
9.6000e-10   -0.88971
9.8000e-10   -0.89272
1.0000e-09   -0.89561
1.0200e-09   -0.89838
1.0400e-09   -0.90104
1.0600e-09   -0.90360
1.0800e-09   -0.90606
1.1000e-09   -0.90842
1.1200e-09   -0.91070
1.1400e-09   -0.91290
1.1600e-09   -0.91501
1.1800e-09   -0.91705
1.2000e-09   -0.91902
1.2200e-09   -0.92091
1.2400e-09   -0.92275
1.2600e-09   -0.92451
1.2800e-09   -0.92622
1.3000e-09   -0.92787
1.3200e-09   -0.92947
1.3400e-09   -0.93101
1.3600e-09   -0.93251
1.3800e-09   -0.93395
1.4000e-09   -0.93535
1.4200e-09   -0.93671
1.4400e-09   -0.93802
1.4600e-09   -0.93929
1.4800e-09   -0.94053
1.5000e-09   -0.94173
1.5200e-09   -0.94289
1.5400e-09   -0.94401
1.5600e-09   -0.94511
1.5800e-09   -0.94617
1.6000e-09   -0.94720
1.6200e-09   -0.94820
1.6400e-09   -0.94918
1.6600e-09   -0.95012
1.6800e-09   -0.95104
1.7000e-09   -0.95194
1.7200e-09   -0.95281
1.7400e-09   -0.95366
1.7600e-09   -0.95448
1.7800e-09   -0.95529
1.8000e-09   -0.95607
1.8200e-09   -0.95683
1.8400e-09   -0.95757
1.8600e-09   -0.95829
1.8800e-09   -0.95900
1.9000e-09   -0.95969
1.9200e-09   -0.96036
1.9400e-09   -0.96101
1.9600e-09   -0.96165
1.9800e-09   -0.96227
2.0000e-09   -0.96288
25.000e-09   -1.00000
LASt_entry

TXT VOUT SCAle 1.0e-03
$V_oc (kV)
TXT IOUT
$I_oc

!
!    ********   Isolation transmisison line   *************************************
!

TRL LIN 10.0E-9  50.0  50.0

TXT  VOUT SCAle 1.0e-03
$V_1_out (kV)
TXT IOUT
$I_TR1_out (A)

!
!    **************  Photocathode 25-Ω TL   *************
!
! Divide the 3.336-ns long TL into 10 segments

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_2_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_3_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_4_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_5_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_6_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_7_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_8_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_9_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_10_out (kV)

TRLine LINear 16.68e-12 25.0  25.0

TXT VOUT SCAle 1.0e-03
$V_11_out (kV)

!
!    ********   Output Isolation transmisison line   *************************************
!

TRL LIN 10.0E-9  50.0  50.0

!

RCGround 1.0e+06 0.00

!
! Termination of Main Branch
!

RCGround 1.0e+04 .0

! End Main Branch (Branch #1)

!
! Level 2 Branches
!
! Branch #2

