Bozyk, L.

Schwickert, M.

Singh, R.

Spiller, P.

Walasek-Höhne, B.

GSI Repository

Streak camera as a new diagnostic tool for SIS18 ion beams∗L. Bozyk, M. Schwickert, R. Singh, P. Spiller, and B. Walasek-Ho¨hneGSI, Darmstadt, GermanyStreak cameras are typically used in electron accelera-tor facilities or plasma physics experiments to record pro-cesses with high time resolution. In 2014 a streak camerahas been installed behind SIS18 at GSI. The streak camerawill be used to study and optimize bunching and extractionof heavy ion beams from the synchrotron by measuring si-multaneously in one spacial and in the time domain.The extracted beam is observed with a BC400 plasticscintillator which is widely used in beam diagnostics. Ithas a rise time of 0.9 ns and decay time of 2.4 ns. It emitslight with a maximal emission at 420 nm (violet/blue). Twoscintillators are mounted in 45◦ with respect to the beamaxis on a target ladder, which can be moved by a steppermotor. The scintillator is observed from below the beamaxis. An optical system, consisting of four lenses and fourmirrors, guides the emitted light to the streak camera. Theoptical system images 30 mm of the scintillator onto the10 mm wide entrance slit of the streak camera, which ob-serves the horizontal plane. Black moleton covering thesetup enhances the contrast by excluding ambient light.The installed streak camera is an ”Universal Streak Cam-era”, model C10910 by Hamamatsu. It allows streak timesbetween 1 ns and 120 ms and has a motorized slit to be fullyremote operable. Sensitive components, as the control PC,are placed in a measurement room, USB and firewire con-nections are extended via optical fibre. The whole systemcan be operated from the main control room of GSI via re-mote desktop access. In the fast extraction mode, the streakcamera is triggered by the same signal, as the kicker mod-ules of SIS18. It is generated in the electronics room bythe Rf-system and has a jitter of 10 ns to 20 ns. By meansof a delay generator one can account for trigger delays andtime-of-flight of the beam. The long streak time of 120 msis used to observe slow extracted beams. In this mode, thesetup is triggered by timing events.In autumn 2014 the streak camera system has been com-missioned with different heavy ion beams from SIS18. Fig-ure 1 shows the time-evolution of the horizontal profile offour bunches U28+ hitting the scintillator. The bunches hitat the same position, but obviously have different intensi-ties. In Figure 2 the projection of streak data of an U29+-beam onto the time axis is compared with the signal of thefast beam current transformer in the extraction line. In fig-ure 3 the flattop voltage was chosen to low. The streakcamera system also allows to resolve the spill structure andmovements of the extracted beam during slow extraction .First test with the streak camera in the SIS18 extractionline look very promising and show good capabilities to ob-serve dynamics within the bunches.∗Work supported by BMBF, projectt 05E12CD1Figure 1: Streak picture of fast extracted U28+ beams at200 MeV with four bunch operation (1H4). 30 pictureshave been averaged.Figure 2: Comparison between the signal recorded withthe beam transformer in the extraction beam line and theprojection of a single streak picture onto the time axis for aU29+-beam in arbitrary units.Figure 3: Screenshot from the online-display with U29+-beam at 210 MeV: The flattop voltage (1 kV) is chosenslightly to low. The deformed bunch can not be recognizedon the beam transformer.FG-SIS18-06 GSI SCIENTIFIC REPORT 2014492 DOI:10.15120/GR-2015-1-FG-SIS18-06

Streak camera as a new diagnostic tool for SIS18 ion beams

http://repository.gsi.de/record/184202/files/FG-SIS18-06.pdf

Streak camera as a new diagnostic tool for SIS18 ion beams

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