Gated mode operation with Hybrid 5

Transcription

1 Gated mode operation with Hybrid 5 J. Dingfelder, L. Germic, T. Hemperek, Jan Cedric Hönig, H. Krüger, F. Lütticke, C. Marinas, B. Paschen, N. Wermes

2 Gated Mode operation Continuous injection of particles (50 Hz) Newly injected particles tend to oscillate more. Injected bunches 100 ns apart! Revolution time 10 µs. Revolution time of 10 µs, while detector read out time is 20 µs Noise created by bunches flying through the detector Gated Mode: Mechanism to make the detector 'blind' to passing bunches! It has been proven that the DEPFET matrix can be operated in 'blind' (gated) mode! Bonn

3 How does gated mode work There are two types of gated mode: With and without read out. Here: Gated mode with read out! Bonn

4 DHP programing Possible to program sequence into DHE memory! DHE adaptercard allows to read out this sequence. Laser DHE adapter makes timing the laser possible DHE Adaptercard DHE Configures, controls and times Sends Data Bonn

5 Adapter for DHE Adapter card warrants the ability to display internal veto and trigger signals! A trigger signal can be sent to the pulse generator connected to the laser. Possibility to program a sequence to control precisely how long is triggered, when gated mode is active and when to shoot the laser. hoenig@physik.uni-bonn.de Bonn

6 DHE memory sequence At the start of the sequence the DHE receives the signal to expect data. At the same time DHP trigger is switched on. At some point gated mode is enabled by the veto signal. Laser is shot twice once during gated mode and once during normal readout. Bonn

7 DHE sequence DHE can be programed to follow a sequence, as soon as the gated mode is activated. In Frame 1 the laser is fired. In Frame 2 positions where the laser has been shot are checked for non cleared charge. In Frame 3 the laser is fired again during gated mode. In Frame 4 it is measured how much charge was injected, despite gated mode shielding. hoenig@physik.uni-bonn.de Bonn

8 Way measurements are evaluated (1) Frame 1 Frame 2 Frame 3 Frame 4 Row number and time move upwards! ADC row column hoenig@physik.uni-bonn.de Bonn

9 Way measurements are evaluated (2) Frame 1 Frame 2 Frame 3 Frame 4 Row number and time move upwards! ADC row column hoenig@physik.uni-bonn.de Bonn

10 Way measurements are evaluated (3) Frame 1 Frame 2 Frame 3 Frame 4 Row number and time move upwards! Cut through the matrix along the hit column! ADC row column hoenig@physik.uni-bonn.de Bonn

11 Way measurements are evaluated (4) Row number and time move to the right! ADC Code Frame 1 Frame 2 No gated mode + Laser is shot No gated mode + Laser is not shot Cut through the matrix along the hit column! Frame 3 Frame 4 Gated mode + Laser is shot No gated mode + Laser is not shot ADC Code row hoenig@physik.uni-bonn.de Bonn row

12 Laser delay measurement Shift laser pulse through veto sequence Start with laser pulses before the beginning of the gated mode sequence. Then delay the laser until it hits in the gated mode sequence. Bonn

13 Laser delay measurement preconditions Row number and time move to the right! Frame 1 Frame 2 No gated mode + Laser is shot Upper part not important for this measurement! No gated mode + Laser is not shot ADC Code Cut through the matrix along the hit column! ADC Code Frame 3 Frame 4 Gated mode + Laser is shot Shift laser through the gated mode sequence! No gated mode + Laser is not shot row hoenig@physik.uni-bonn.de Bonn row

14 What do we expect? 1.) One shoots shortly before the gated mode sequence. The injected charge is measured twice. Once during gated mode and then again after gated mode. 2.) One shoots during gated mode. The injected charge is hindered from reaching the internal gate. Thus no signal is measured. 3.) One shoots after the gated mode sequence. The signal appears in the next frame. The following measurements contain an offset of 3x8 = 24 GCK, obtained in separate measurements about laser delay! hoenig@physik.uni-bonn.de Bonn

15 What do we see? Plot only shows frame 4 for different laser delays! ADC ADC rows rows rows rows rows rows hoenig@physik.uni-bonn.de Bonn

16 Pixel inside gated area Before start of GM sequence Measured pixel is being read out ADC ADC rows rows rows rows rows rows End of gated mode sequence Bonn

17 Scan different area Shift measurement point from gated area to pixel outside the gated area. But shoot while pixels are gated! Bonn

18 Pixel outside of the gated region Plot shows signal after gated mode for different laser delays! ADC ADC rows rows rows rows rows rows Bonn

19 Clear high gate off measurement (perquisite) Complete set of standard voltages: Source: 7000 mv Scan of clear low and clear high: Potential wall height important! Gate off: Gate on: Clear gate: Clear on: Clear off: 3000 mv mv mv mv 6000 mv Gate Off: mv step size: 500 mv High voltage: Drift: mv mv Clear high: mv step size: 1000 mv Bonn

20 Gate off [mv] Signal [ADC Units] Clear high gate off (outside pixel) charge preservation Added common mode correction Clear high [mv] Bonn

21 What challenges are there with gated mode? Row number and time move upwards! Frame 1 Frame 2 Frame 3 Frame 4 Increased pedestals No common mode correction active! ADC row column hoenig@physik.uni-bonn.de Bonn

22 Clear high clear low measurement (perquisite) Complete set of standard voltages: Scan of clear low and clear high: Clear low: mv step size: 250 mv Clear high: mv step size: 250 mv Source: Gate off: Gate on: Clear gate: Clear on: Clear off: High voltage: Drift: 7000 mv 3000 mv mv mv mv 6000 mv mv mv Bonn

23 Clear high clear low measurement Following plots are for a pixel inside of the GM region! hoenig@physik.uni-bonn.de Bonn

24 Clear high clear low measurement no gated mode Clear high [mv] Bonn

25 Clear high clear low measurement gated mode Non working area Clear high [mv] Bonn

26 Why do low clear low voltages not work? High pedestals Clear high: mv Clear low: 2000 mv Pixel columns Bonn

27 Clear low measurement high clear low do not work ADC code Frame 1 No gated mode + Laser is shot Clear high: mv Clear low: 8000 mv Frame 2 No gated mode + Laser is not shot ADC code Frame 3 Gated mode + Laser is shot Frame 4 No gated mode + Laser is not shot Row # Row # hoenig@physik.uni-bonn.de Bonn

28 Clear high clear low measurement gated mode Non working area Clear high [mv] Bonn

29 Clear high measurement (working point) ADC code Frame 1 No gated mode + Laser is shot Clear high: mv Clear low: 6000 mv Frame 2 No gated mode + Laser is not shot ADC code Frame 3 Gated mode + Laser is shot Frame 4 No gated mode + Laser is not shot Row # Row # hoenig@physik.uni-bonn.de Bonn

30 Clear high measurement (overview) Clear high: mv Clear high: mv Signal is not properly cleared after injection. Gated mode does not work correctly. Clear high: mv Signal is properly cleared after injection! But going out of gated mode creates large pedestal oscillations! Clear low: 6000 mv Bonn

31 Clear high measurement (extreme case) gated mode ADC code Frame 1 No gated mode + Laser is shot Clear high: mv Clear low: 6000 mv Frame 2 No gated mode + Laser is not shot Signal is properly cleared after injection! But going out of gated mode creates large pedestal oscillations! ADC code Frame 3 Gated mode + Laser is shot Frame 4 No gated mode + Laser is not shot Row # Row # hoenig@physik.uni-bonn.de Bonn

32 Clear high clear low scan different area Shift measurement point from gated area to pixel outside the gated area. But shoot while pixels are gated! Bonn

33 Clear low [mv] Signal [ADC Units] Clear high clear low (outside pixel) shielding Added common mode correction Non working area Clear high [mv] Bonn

34 Clear high clear low charge preservation How much of the injected charge remains inside the internal gate during gated mode? Bonn

35 Clear low [mv] Signal [ADC Units] Clear high clear low (outside pixel) charge preservation Added common mode correction Input signal How much of the injected charge remains inside the internal gate during gated mode? Clear high [mv] Non working area Bonn

36 What challenges are there with gated mode? Row number and time move upwards! Frame 1 Frame 2 Frame 3 Frame 4 Increased pedestals No common mode correction active! ADC row column hoenig@physik.uni-bonn.de Bonn

37 What challenges are there with gated mode? Row number and time move upwards! Frame 1 Frame 2 Frame 3 Frame 4 Increased pedestals No common mode correction active! ADC row With adapted voltages column hoenig@physik.uni-bonn.de Bonn

38 DHE sequence DHE can be programed to follow a sequence, as soon as the gated mode is activated. In Frame 1 the laser is fired. In Frame 2 positions where the laser has been shot are checked for non cleared charge. In Frame 3 the laser is fired again during gated mode. In Frame 4 it is measured how much charge was injected, despite gated mode shielding. hoenig@physik.uni-bonn.de Bonn

39 Y coordinate [moco] Position dependent scans How strongly does gated mode s performance depend on the location where charge is injected? Pixel outside of gated region! ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

40 Y coordinate [moco] Cluster signal (shielding) laser shot for 4 GCK Reference: How much charge was injected, on average? Pixel outside of gated region! Measurement: How much charge was measured despite shielding? ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

41 Y coordinate [moco] Cluster signal (shielding) laser shot for 2 GCK Reference: How much charge was injected, on average? Pixel inside of gated region! Measurement: How much charge was measured despite shielding? ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

42 Y coordinate [moco] Cluster signal (preservation) laser shot for 4 GCK Reference: How much charge was injected, on average? Pixel outside of gated region! Measurement: How much charge was preserved during gated mode? ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

43 Y coordinate [moco] Cluster signal (preservation) laser shot for 2 GCK Reference: How much charge was injected, on average? Pixel inside of gated region! Measurement: How much charge was preserved during gated mode? ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

44 Outlook and conclusion Measurements: How DEPFET behaves while going in and out of gated mode: Pedestal increase due to quick switching of clear signal when going out of gated mode How gate off voltage influences shielding efficiency. Minimal gate off voltage required How clear low and clear high influence gated mode performance: Gated mode sets an upper limit for clear high Position dependent performance measurements: Differences between pixels, but location where charge is injected inside a pixel not important Still needed are position dependent optimization of clear low, clear high and gate off voltage! hoenig@physik.uni-bonn.de Bonn

45 Conclusions Gated mode with readout proven to work (charge removal/charge preservation) Set of suggested optimized voltages: ClearHigh = V ClearLow = 6 V GateOff = 3 V Timing: Going in and out of gated mode ~200 ns (+ gated time itself) on H5 system and small matrix. Still further optimization is needed. Some issues to understand: Extrapolation to large matrices (~800 ns?) Further understanding up/down matrix effects while going into gated mode operation hoenig@physik.uni-bonn.de Bonn

46 Thank you Bonn

47 Backup

48 Y coordinate [moco] Cluster signal (shielding) laser shot for 4 GCK GM efficiency Pixel outside of gated region! Measurement: How much charge was measured despite shielding? ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

49 Y coordinate [moco] Cluster signal (shielding) laser shot for 2 GCK GM efficiency Pixel inside of gated region! Measurement: How much charge was measured despite shielding? ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

50 Y coordinate [moco] Cluster signal (preservation) laser shot for 2 GCK Reference: How much charge was injected, on average? Pixel inside of gated region! Measurement: How much charge was preserved during gated mode? ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

51 Clear low [mv] Signal [ADC Units] Clear high clear low (outside pixel) gated mode Added common mode correction Non working area Clear high [mv] Bonn

52 DHP programing Trigger Trigger pulse given at position 5 DHE Configures, controls and times Sends Data hoenig@physik.uni-bonn.de Bonn

53 Seed signal laser shot for 1 gate Frame 1 No gated mode + Laser is shot ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

54 Seed signal after gated mode laser shot for 1 gate Frame 4 No gated mode + Laser is not shot ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

55 Seed signal after gated mode laser shot for 2 gate Frame 4 No gated mode + Laser is not shot Same picture if laser signal is doubled! ADC code X coordinate [moco] hoenig@physik.uni-bonn.de Bonn

56 What to optimize Multiple paths which need to be checked for correct functionality. So far worked on optimizing DCD performance. DHE Configures, controls and times Sends Data Bonn

57 DCD optimization DCD is part of the electronics directly connected to the matrix. It is responsible for digitizing the signal current generated in the matrix. Half speed Low gain Optimize DCD for: - range of curve - linearity - missing codes/bit errors - noise hoenig@physik.uni-bonn.de Bonn

58 DCD measurement Optimization done with 2D scans over multiple channels. Quality of each curve is determined with the earlier mentioned criteria for all measured channels (256 DCD channels). Bonn

59 DCD measurement and evaluation Quality of each configuration is determined by counting number of tests not passed. Best working point lowest value Bonn

60 What is the DCD DCD Plenty of voltages to change. Important ones are: RefIn, AmpLow, VPSource, VPSource2, VFBPBias Bonn