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

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List of Tables 2.3.1 R 56 and R 16 values for FLASH and XFEL, the corresponding dynamic apertures of the chicanes (X range) and the position spreads of the beam within the chicanes (DX). 3.1.1 Module controller performance benchmarks 4 4.3.1 Contributions to first bunch compressor beam tilt for an off-crest bunch. 6.8.1 Effects of beam tilts on beam position measured with transversely mounted stripline BPM. 7.5.1 Rough cost estimate of RF front-end and optical front-end for the chicane BPM. 8.1.1 Costs and performance of RF cables and optical fibers. 8.1.2 Rough cost estimate for a 20 fs resolution RF arrival-time monitor with a 100 fs phase-stabilized cable. 8.2.1 Comparison of optical and RF systems phase noise, detection, and etc. 8.2.2 Cost estimate for 6 fs resolution optical front-end and a length-stabilized fiber. 8.3.1 The cost of an MO in a rack and an MLO with optical table and control hardware. 10.0.1 Comparison of energy measurements in the first bunch compressor.
List of Figures 1.0.1 Magnetic bunch compressor chicane. 2.0.1 Free-electron LASer in Hamburg (FLASH). 2.1.1 Simplified cross-section of the RF Gun. 2.2.1 Basic structure of a klystron. 2.3.1 The phase of the accelerating RF relative to the beam determines the energy chirp of the beam. 2.3.2 Bunch profiles in the first bunch compressor for inhomogeneous compression without the third-harmonic cavity. 2.3.3 Energy spread generated within chicane breaks linear achromaticity and results in an increased emittance after the chicane. 2.3.4 Single chicane (a) and symmetric double-chicane (b). 2.4.1 Undulator magnet and electron bunch producing synchrotron radiation. 2.4.2 Interaction of electron beam and photon pulse. 3.1.1 System for controlling the cavity fields of the accelerating module. 3.1.2 Simplified block diagram of the cavity regulation routines on the FPGA. 3.1.3 A desired FPGA algorithm structure incorporating reference injection and beam-based information. 3.2.1 Transformation of arrival-time jitter with an accelerating section followed by a bunch compressor. 3.3.1 Layout of synchronization sensitive components at FLASH, along with desired feedback loops. 3.4.1 Measurement of the arrival-time of the injector laser pulse relative to a timing laser reference (MLO) using a two-color single-crystal balanced optical cross-correlator. 4.2.1 The shape of the beam in the bunch compressor for on-crest operation, as viewed on the synchrotron light monitor in the first bunch compressor. 4.2.2 Coupler kick concept. 4.2.3 Coupler geometry with pickups (top) and voltage of kick (bottom). 4.2.4 Voltages acting on a beam as it travels in z through a cavity tilted in the y- z plane. 4.2.5 The effect of a dipole force on a beam with an energy chirp. 4.2.6 A beam offset in the injector is magnified as it travels through the first accelerating section. 4.2.7 A lattice optimized for a space-charge dominated beam magnifies beam tilts generated in the injector. 4.3.1 The tilt of the beam for various closed orbit bumps through the first accelerating section. 4.3.2 Images on the screen contain projections of the beam streaked out in a longitudinal direction. 4.3.3 Simulation results for energy spread of the beam coming out of the injector (top-left), the horizontal beam path through the accelerating module (top-right), and the resulting tilt in the first bunch compressor with (bottom-left) and without (bottom-right) the chromatic effect of the quadrupoles.
Page 1 and 2: Measuring the Electron Beam Energy
Page 3 and 4: Abstract Within this thesis, work w
Page 5: 9 Synchrotron Light Monitors 9.1 Pr
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
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E (MeV) 4.75 4.74 4.73 4.72 4.71 4.
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leads one to suspect that as in the
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vacuum feedthroughs, the buttons we
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J image − ⎡ ⎛ ⎞ ⎤ = ⎢ +
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sensitivity of 8 and 20 mm diameter
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1 v phase = . (5.1.21) LC Finally,
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some locations. Nevertheless, it is
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BPM BAM More power at lower frequen
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arrival-time monitor with and witho
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5.2 Cavity BPM Cavity BPMs (Fig. 5.
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t=0 Z 0 t=L/c Z 0 2L Figure 5.3.1 L
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0.2 nC beam charge and can handle b
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T1-T2=T3 X=T3*c T1 T2 Figure 5.5.2
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None of the designs suffered from a
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pickup functions appropriately over
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35 Measured BPM Vertical amplitude
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2.5 Beam position 2 position (cm) 1
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L( x0 , t) U 0 ( t) = λ( x0 , t) (
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1 x beam = ) xdtdx Q ∫∫λ ( x,
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0 BPM beam width dependence arrival
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100 Vertical y position sensitiviy
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Such an x-y tilt was measured with
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10 5 head x [mm] 0 tail -5 -5 -4 -3
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3.5 x 10-3 Horizontal Charge Distri
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The problem that could arise due to
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around their zero-crossings in orde
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v i ( i i i t) = A sin(2π f t + θ
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strengths of the peaks seen in Fig.
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algorithm required to select the ph
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Downmixers for EBPM BPM-L BPM-R BPM
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While this option was not built and
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A Peltier element acts as a heat pu
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For the measurement shown in Fig. 7
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2 1.5 1 BC2 x position (mm) 0.5 0 -
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0 BC2 arrival time (ps) 1.5 1 0.5 0
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eality check BC2 PMT EBPM and PMT p
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EBPM and PM positions (mm) 6 5 4 3
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If a limiter or nothing at all is u
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Depending on the arrival-time of th
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20mW to BAM FARADAY 8m 80/20 60mW W
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can be placed anywhere prior to the
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Insulation Peltier element on metal
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using the RF limiter. This might be
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compared. The length of the cable c
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eplaced with fiber. The advantage o
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Photodetector Photodetector Two las
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RF-Lock Box for FLASH MLO Synchroni
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In Fig. 8.3.4, the spectral noise d
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Mixer Output (fs) 40 20 0 -20 MLO R
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For a frame of reference concerning
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(Fig. 9.1.2). This method proved to
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N λ ∞ ∫ ω / ω Δω 9 3 ( ω)
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Finally, we can use this, together
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The highest energy resolution (ΔE/
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Good agreement between the RF chica
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10.3 Out-of-loop Vector Sum The out
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out. This was done in two ways: by
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1.8 1.6 stripline button 1.4 Upstre
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10 Conclusion and Outlook Six disti
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Appendix A The derivation of Eqs. 3
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Solving Eq. 8 for E 1 ’ provides
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Higher order terms and the 3 rd -ha
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∂t ∂V 2 2 ⋅ ΔV 2 1 = T1 '( E
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References [1] P. Castro. “Beam t
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[28] H. Schlarb et al., “Beam bas
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[55] C. Gerth, personal communicati
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Measuring the Electron Beam Energy in a Magnetic Bunch ... - DESY

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