Measuring the Electron Beam Energy in a Magnetic Bunch ... - DESY

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Contents 1 Introduction 2 Free Electron Lasers 2.1 RF Photo-injector 2.2 Accelerating Section 2.3 Bunch compression 2.4 Undulator section 3 Beam Arrival-time stabilization 3.1 Baseline Control 3.2 Arrival-time Changes after a Bunch Compressor 3.3 Beam-based Feedback Strategy 3.4 Injector Jitter 3.5 Third-harmonic Module Jitter 3.6 First Accelerating Section Jitter 3.7 Second Accelerating Section Jitter 3.8 Outlook 4 Beam Shape and Orientation in and around the Bunch Compressor 4.1 Perfect Alignment 4.2 Misaligned Injector 4.3 Downstream of the Injector 5 Beam Pickups 5.1 Button Pickups 5.2 Cavity BPM 5.4 Stripline Pickups 5.3 Array of Striplines 5.5 Transversely-mounted Stripline 6 Impacts of Beam Shape and Orientation 6.1 Pickup Signals from a Wide Beam 6.2 Beam Width Changes 6.3 Tilted in x-z plane 6.4 Tilted in y-z plane 6.5 Tilted in x-z plane 6.6 Asymmetric Charge Distribution Tilted 6.7 Fields from Previous Positions 6.8 Summary 7 Chicane BPM front-end 7.1 RF Front-end Concept 7.2 RF Front-end Execution 7.3 Optical Front-end Concept 7.4 Optical Front-end Execution 7.5 Front-end costs 8 Beam Arrival-time Monitors 8.1 RF Front-end 8.2 Optical Front-end 8.3 MLO RF-lock
9 Synchrotron Light Monitors 9.1 Profile Monitors 9.2 Photomultiplier Tube Monitors 10 Energy Measurement Benchmarking 10.1 RF BPM Measurements 10.2 Photomultipler Tube Monitor 10.3 Out-of-loop Vector Sum 10.4 Optical BPM Measurements 11 Conclusion and Outlook
Page 1 and 2: Measuring the Electron Beam Energy
Page 3: Abstract Within this thesis, work w
Page 7 and 8: List of Figures 1.0.1 Magnetic bunc
Page 9 and 10: 5.5.10 Dependence of the slope of p
Page 11 and 12: 8.3.6 RF phase measurement drift wi
Page 13 and 14: where α is the bending angle intro
Page 15 and 16: R 16 ( eBl / 2) d ⎛ ⎞ 1 eff 2 p
Page 17 and 18: 2 Free-electron Lasers The facility
Page 19 and 20: arrival-time and energy prior to a
Page 21 and 22: electrons travel faster than low-en
Page 23 and 24: efore bunch compressor energy chirp
Page 25 and 26: corresponds to terms that are linea
Page 27 and 28: spread will be larger and the trans
Page 29 and 30: (a) (b) Figure 2.3.4 Single chicane
Page 31 and 32: 3 Beam Arrival-time Stabilization A
Page 33 and 34: changes in the amplitude of the kly
Page 35 and 36: The problem of cavity field measure
Page 37 and 38: creates a single point-of-failure s
Page 39 and 40: accelerator section and it was firs
Page 41 and 42: ACC1 ~Gun 3rd ACC2 ACC3ACC4 ACC7 Ac
Page 43 and 44: • The lack of a normal-conducting
Page 45 and 46: ( ) E − E ⎛ E − E ⎜ ⎝ 0 0
Page 47 and 48: 3.7 Second Accelerator Section Jitt
Page 49 and 50: 4 Beam Shape in the Bunch Compresso
Page 51 and 52: There has been some debate over the
Page 53 and 54: V T = V cos( k ⋅ z + = V T 0 rf
Page 55 and 56:
Upstream of the first accelerator s
Page 57 and 58:
Positive bump 5 8 deg off-crest in
Page 59 and 60:
E (MeV) 4.75 4.74 4.73 4.72 4.71 4.
Page 61 and 62:
leads one to suspect that as in the
Page 63 and 64:
vacuum feedthroughs, the buttons we
Page 65 and 66:
J image − ⎡ ⎛ ⎞ ⎤ = ⎢ +
Page 67 and 68:
sensitivity of 8 and 20 mm diameter
Page 69 and 70:
1 v phase = . (5.1.21) LC Finally,
Page 71 and 72:
some locations. Nevertheless, it is
Page 73 and 74:
BPM BAM More power at lower frequen
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arrival-time monitor with and witho
Page 77 and 78:
5.2 Cavity BPM Cavity BPMs (Fig. 5.
Page 79 and 80:
t=0 Z 0 t=L/c Z 0 2L Figure 5.3.1 L
Page 81 and 82:
0.2 nC beam charge and can handle b
Page 83 and 84:
T1-T2=T3 X=T3*c T1 T2 Figure 5.5.2
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None of the designs suffered from a
Page 87 and 88:
pickup functions appropriately over
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35 Measured BPM Vertical amplitude
Page 91 and 92:
2.5 Beam position 2 position (cm) 1
Page 93 and 94:
L( x0 , t) U 0 ( t) = λ( x0 , t) (
Page 95 and 96:
1 x beam = ) xdtdx Q ∫∫λ ( x,
Page 97 and 98:
0 BPM beam width dependence arrival
Page 99 and 100:
100 Vertical y position sensitiviy
Page 101 and 102:
Such an x-y tilt was measured with
Page 103 and 104:
10 5 head x [mm] 0 tail -5 -5 -4 -3
Page 105 and 106:
3.5 x 10-3 Horizontal Charge Distri
Page 107 and 108:
The problem that could arise due to
Page 109 and 110:
around their zero-crossings in orde
Page 111 and 112:
v i ( i i i t) = A sin(2π f t + θ
Page 113 and 114:
strengths of the peaks seen in Fig.
Page 115 and 116:
algorithm required to select the ph
Page 117 and 118:
Downmixers for EBPM BPM-L BPM-R BPM
Page 119 and 120:
While this option was not built and
Page 121 and 122:
A Peltier element acts as a heat pu
Page 123 and 124:
For the measurement shown in Fig. 7
Page 125 and 126:
2 1.5 1 BC2 x position (mm) 0.5 0 -
Page 127 and 128:
0 BC2 arrival time (ps) 1.5 1 0.5 0
Page 129 and 130:
eality check BC2 PMT EBPM and PMT p
Page 131 and 132:
EBPM and PM positions (mm) 6 5 4 3
Page 133 and 134:
If a limiter or nothing at all is u
Page 135 and 136:
Depending on the arrival-time of th
Page 137 and 138:
20mW to BAM FARADAY 8m 80/20 60mW W
Page 139 and 140:
can be placed anywhere prior to the
Page 141 and 142:
Insulation Peltier element on metal
Page 143 and 144:
using the RF limiter. This might be
Page 145 and 146:
compared. The length of the cable c
Page 147 and 148:
eplaced with fiber. The advantage o
Page 149 and 150:
Photodetector Photodetector Two las
Page 151 and 152:
RF-Lock Box for FLASH MLO Synchroni
Page 153 and 154:
In Fig. 8.3.4, the spectral noise d
Page 155 and 156:
Mixer Output (fs) 40 20 0 -20 MLO R
Page 157 and 158:
For a frame of reference concerning
Page 159 and 160:
(Fig. 9.1.2). This method proved to
Page 161 and 162:
N λ ∞ ∫ ω / ω Δω 9 3 ( ω)
Page 163 and 164:
Finally, we can use this, together
Page 165 and 166:
The highest energy resolution (ΔE/
Page 167 and 168:
Good agreement between the RF chica
Page 169 and 170:
10.3 Out-of-loop Vector Sum The out
Page 171 and 172:
out. This was done in two ways: by
Page 173 and 174:
1.8 1.6 stripline button 1.4 Upstre
Page 175 and 176:
10 Conclusion and Outlook Six disti
Page 177 and 178:
Appendix A The derivation of Eqs. 3
Page 179 and 180:
Solving Eq. 8 for E 1 ’ provides
Page 181 and 182:
Higher order terms and the 3 rd -ha
Page 183 and 184:
∂t ∂V 2 2 ⋅ ΔV 2 1 = T1 '( E
Page 185 and 186:
References [1] P. Castro. “Beam t
Page 187 and 188:
[28] H. Schlarb et al., “Beam bas
Page 189 and 190:
[55] C. Gerth, personal communicati
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Measuring the Electron Beam Energy in a Magnetic Bunch ... - DESY

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