Up one level
2011-06-21_01 Adapter SHV to BNC to connect the moderator directly to the oscillocope 2011-06-21_02 Oscillogram of moderator pulse with +2kV bias at moderator foil. Yellow pulse: MINT pulse used for triggering. 2011-06-21_03 Oscillogram of moderator pulse with +0kV bias at moderator foil (grounded over capacity) 2011-06-21_04 Oscillogram of moderator pulse with +0kV bias at moderator foil (directly connected to oszilloscope with 1 MOhm input resistance) 2011-06-21_05 Andreas Müller soldering the SHV adaptor. 2011-06-21_06 Marco Jungmann 2011-06-21_07 Marx pulser for chopper pulsing mounted at MePS system. 2011-06-21_07a The Marx generator. 2011-06-21_07b The pulse of the Marx generator (new version of June 2011). At 150V the pulse is about 4 ns wide. 2011-06-21_08 The chopper generator with two fans. 2011-06-21_09 Time is running, Ulf too. 2011-06-21_10 Ulf adjusted a thin foil between the two Be windoes to show the beam position. The foil is sensitive to high energy radiation. There were two different foils with different sensitivity. 2011-06-21_11 The two Be windows in the back of the beamline. The W aperture with heat sink is also visible. 2011-06-21_12 Ulf puts the film in place. 2011-06-21_13 Film in position. 2011-06-21_14 The WinCC control panel of ELBE. 2011-06-21_15 20 pulses are programmed with 0.1 ms period in single pulse mode to hit the film. 2011-06-21_16 The most impotant keys at ELBE. 2011-06-21_17 The first attempt: Film is exposed and shows the diameter of the aperture. Most probably the dark current was responsible. We will try again with a less sensitive film.... 2011-06-21_18 Both chopper stages visible with aperture between them. 2011-06-21_19 The last chopper and bellow for the beam line. 2011-06-21_20 The increase of the resistance of a W filament which is behind the positron converter shows that the beam hits the converter. The increase is distinct > 40%. 2011-06-21_21 Ulf is going to install the less sensitive film. 2011-06-21_22 The result looks much better. 2011-06-21_23 2011-06-21_24 2011-06-21_25 The beam profile is visible. 2011-06-21_26 Andreas is preparing for departure after beam time.