THz proof-of-principle experiment at PITZ S2E simulations of THz SASE FEL at PITZ with LCLS-I undulator Mikhail Krasilnikov Mini-workshop on THz proof-of-principle experiment at PITZ DESY, Hamburg, 12.10.2018
IR/THz SASE source for pump-probe experiments @E-XFEL PITZ-like accelerator can enable high power, tunable, synchronized IR/THz radiation Pump X-ray European XFEL (~3.4 km) PITZ-like accelerator based & THz source (~20 m) Transverse profile probe THz correction E.A. Schneydmiller, M.V. Yurkov, (DESY, Hamburg), M. Krasilnikov, F. Stephan, (DESY, Zeuthen), “ Tunabale IR/THz source for pump probe experiments at the European XFEL, Contribution to FEL 2012, Nara, Japan, August 2012 • Accelerator based IR/THz source meets requirements for pump-probe experiments (e.g. the same pulse train structure !) • Construction of radiation shielded area for installing reduced copy of PITZ is possible close to user experiments at E-XFEL • Prototype of accelerator already exists PITZ facility at DESY in Zeuthen e.g. in E-XFEL photon beam line tunnel: Simulation of THz SASE FEL @PITZ λ = 100µm E-XFEL p-p laser Photo by Dirk Noelle, 06.06.2013 Required beam ( ~4nC, I peak ~200A ) based on plot of M. Gensch already demonstrated at PITZ PITZ can be used for proof of principle and optimization! | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 2
Planned installation of LCLS-I undulators in PITZ tunnel annex Will be used for proof-of-principle experiments at PITZ | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 3
SASE FEL based on PITZ accelerator and LCLS-I undulators LCLS-I undulators (available on loan from SLAC) under study and negotiations E- beam with PITZ parameters “ideally” matched into the undulator Some Properties of the LCLS-I undulator Preliminary GENESIS Simulations ( l rad =100 m m) Properties Details 2.68 mJ Type planar hybrid (NdFeB) K-value 3.49 (3.585) Support diameter / length 30 cm / 3.4 m 1.06 mJ Vacuum chamber size 11 mm x 5 mm Period length 30 mm Matching section Periods / a module 113 periods U1 U2 Reference: LCLS conceptual design report, SLAC-0593, 2002. Preliminary conclusions on LCLS-I undulators at PITZ: ‣ Not such extremely high performance as for the APPLE-II, but is clearly proper for the proof-of-principle experiment! ‣ 4 nC electron beam transport through the vacuum chamber needs efforts, but seems to be feasible. l rad ~100 m m <Pz>=16.7MeV/c | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 4
Beam Dynamics Simulation Setup ASTRA, SC-optimizer Gun +Solenoids + CDS-booster Photocathode laser Photocathode laser: • FT 21.5ps FWHM • ∅ ≤ 5mm Gun: • 4nC • Ecath=60MV/m (fixed) NB: • MMMG • Core + Halo model for real laser! Booster: • Imperfections (photoemission • Emax<20MV/m <Pz>=16.7MeV/c + min d E@undulator? + asymmetry) • Phase=phi2* | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 5
Gun, solenoid, booster parameters Extremely small emittance is not a goal phi2* = booster Photocath.laser: phase for XYrms=1.25mm <Pz>=16.7MeV/c Booster: MaxE(2)= 12.6MV/m Phi(2)= -24deg Gun solenoid: MaxB(1)=-0.21285T | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 6
Beam at EMSY1 – “ready” for transport Z=5.277m from the cathode | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 7
Estimations on beam size in a drift Based on ASTRA simulations with space charge 2 1 3 5 3 2 5 4 1 “Ideal” (Gaussian -FT) electron beam: • Q=4nC • <Pz>=16.7MeV/c 4 ~4 mm mrad • can be transported through pipe: • L=3.4m 5mm • | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 8
PITZ Beam from the cathode tunnel wall ASTRA SC-optimizer HIGH2.Q2 PST.QT3 HIGH1.Q3 HIGH1.Q7 HIGH3.Q1 HIGH3.Q3 HIGH1.Q5 PST.QT6 HIGH3.Q2 HIGH3.Q1-3 – assumed (not existing) NB: ASTRA Space Charge 3D: 𝑀 200k particles N x,y,z =16 13 part/cell 1 𝐻𝐺(𝑅 1 , … , 𝑅 9 ) ∝ 𝑀 𝑌 rms ∙ 𝑍 rms 𝑒𝑨 200k particles N x,y,z =32 191 part/cell 0 | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 9
PITZ Beam from the cathode tunnel wall ASTRA check HIGH2.Q2 PST.QT3 HIGH1.Q3 HIGH1.Q7 HIGH3.Q1 HIGH3.Q3 HIGH1.Q5 PST.QT6 HIGH3.Q2 HIGH3.Q1-3 – assumed (not existing) | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 10
PITZ Beam from the cathode tunnel wall Beam emittance using SC-optimizer and ASTRA S2E simulations: 4nC 16.7MeV/c beam transport from the cathode till and through the tunnel wall OK | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 11
LCLS-I Undulator field By(z) field profile measurements done on 02.10.2013 at SLAC for the undulator L143-112000-07 after the final tuning Based on file x+00000_y+000_bscanz.dat (communication with Heinz-Dieter Nuhn from 06.07.2018) | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 12
LCLS-I Undulator field By(z) field profile measurements done on 02.10.2013 at SLAC for the undulator L143-112000-07 after the final tuning Based on file x+00000_y+000_bscanz.dat (communication with Heinz-Dieter Nuhn from 06.07.2018) | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 13
LCLS-I Undulator field Fourier Analysis Performing Fourier transformation for − 𝑀 2 ≤ 𝑨 ≤ 𝑀 2 , where 𝑀 = 𝑂 𝑉 𝜇 𝑉 is the undulator length: 2𝜌𝑜𝑨 2𝜌𝑜𝑨 ∞ 𝐶 𝑧 𝑦 = 0, 𝑧 = 0, 𝑨 = 𝑏 𝑜 cos 𝑂 𝑉 𝜇 𝑉 + 𝑐 𝑜 sin , 𝑜=0 𝑂 𝑉 𝜇 𝑉 where 𝑀 2 2𝜌𝑜𝑨 𝑏 𝑜 = 2 𝐶 𝑧 𝑦 = 0, 𝑧 = 0, 𝑨 cos 𝑂 𝑉 𝜇 𝑉 𝑒𝑨 , 𝑀 − 𝑀 2 𝑀 𝑏 0 = 1 𝐶 𝑧 𝑦 = 0, 𝑧 = 0, 𝑨 𝑒𝑨 , 𝑀 2 − 𝑀 2 𝑀 2 2𝜌𝑜𝑨 𝑐 𝑜 = 2 𝐶 𝑧 𝑦 = 0, 𝑧 = 0, 𝑨 sin 𝑂 𝑉 𝜇 𝑉 𝑒𝑨 . 𝑀 − 𝑀 2 Field integrals of the undulator: 𝑀 𝐽 1𝑧 = 2 𝐶 𝑧 𝑦 = 0, 𝑧 = 0, 𝑨 𝑒𝑨 , 𝐽 1𝑧 = 𝑏 0 𝑀 , 𝑏 0 = 0 − 𝑀 ∞ 2 −1 𝑜 ∞ 𝑀 𝐽 2𝑧 = 𝑀 2 2 𝑏 0 + −1 𝑜 𝑨 𝑐 𝑜 = 0 𝐽 2𝑧 = 2 𝑒𝑨 𝐶 𝑧 𝑦 = 0, 𝑧 = 0, 𝑨 1 𝑒𝑨 1 . 𝑐 𝑜 − 𝑀 𝜌𝑜 − 𝑀 𝜌𝑜 2 𝑜=1 2 𝑜=1 | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 14
LCLS-I Undulator field “Improving “ the field profile 2𝜌𝑜𝑨 2𝜌𝑜𝑨 𝑂 ℎ ∙𝑂 𝑉 𝑜 sin 𝐶 𝑧,2 0,0, 𝑨 = 𝑏 𝑜 cos 𝑂 𝑉 𝜇 𝑉 + 𝑐 𝑜=1 𝑂 𝑉 𝜇 𝑉 | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 15
LCLS-I Undulator field 3D field map generation Utilizing 𝜊 2𝑛 𝜊 2𝑛+1 ∞ ∞ = cosh 𝜊 , = sinh 𝜊 , 𝑛=0 𝑛=0 2𝑛 ! 2𝑛+1 ! Vertical and longitudinal components can be finally re-written: 𝑂 ℎ ∙𝑂 𝑉 𝑜 sin 𝑙 𝑜 𝑨 𝐶 𝑧 = 𝑏 𝑜 cos 𝑙 𝑜 𝑨 + 𝑐 ∙ cosh 𝑙 𝑜 𝑧 , 𝑜=1 𝑂 ℎ ∙𝑂 𝑉 𝑜 cos 𝑙 𝑜 𝑨 𝐶 𝑨 = −𝑏 𝑜 sin 𝑙 𝑜 𝑨 + 𝑐 ∙ sinh 𝑙 𝑜 𝑧 , 𝑜=1 where 𝑙 𝑜 = 2𝜌𝑜 𝑂 𝑉 𝜇 𝑉 is the wavenumber of the n -th Fourier harmonic. | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 16
On-axis particle trajectory in the undulator ASTRA reference particle and CST tracking Undulator field profile ASTRA with 3D field map CST Particle Studio Trk used for field map generation Raw measurements Improved profile Vertical on-axis trajectory y=0 | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 17
Off-axis particle trajectory in the undulator ASTRA reference particle case 5 y=1mm 5 22 y=0.3mm 0 case 22 (better y-matching) case X(0), mm X’(0), mrad Y(0), mm Y’(0), mrad 5 0.7 -0.35 0.7 -0.35 22 0.7 -0.35 0.21 -1.19 | PITZ facility overview | Mikhail Krasilnikov, mini-workshop on THz proof-of-principle experiment at PITZ, 12.10.2018 Page 18
Recommend
More recommend
