1 / 20

Production #291

Production #291. HV. Before After. 3. 7. 12. 2. 1. HV. Production # 503. HV. Before After. HV. Diode scan (no HV) from damaged tube fromCERN HPD #291. Setup and readout. B. HV =10 kV. Keithly 80 V BIAS and ampmeter. 80.00 V. 05.956 nA. LED pulser. Ortec Preamp A~0.5 mv/pe.

ady
Download Presentation

Production #291

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Production #291 HV Before After 3 7 12 2 1 HV

  2. Production # 503 HV Before After HV

  3. Diode scan (no HV) from damaged tube fromCERN HPD #291

  4. Setup and readout B HV =10 kV Keithly 80 V BIAS and ampmeter 80.00 V 05.956 nA LED pulser Ortec Preamp A~0.5 mv/pe

  5. We see the same noise at CERN in B-field (Ortec amplifier is a QI, fast rise time and slow decay)

  6. We can see the small pulses with keithly bias supply Without amplifier we see also large pulses in bursts

  7. When getting on an angle small pulses increase but large ones disappear

  8. Pulse shape of large pulses seen in the two pixels (smaller ones are later in time) At 10 V bias pulse becomes very wide(10 micro seconds) > so it looks like a real photo current

  9. Two pulses seen in two opposite side pixels Here PIXEL 1 is the biggest (smaller ones are later in time)

  10. Two pulses pulses seen in two opposite side pixels Here PIXEL 19 is the biggest (smaller ones are always later in time)

  11. Relation between Large and small noise signals We triggered on the big pulse in channel 5 and look at the amplified signal from Pixel 10 (small pulses disappear for some time after a big pulse ) AC coupling to scope Total 4 ms

  12. Relation between Large and small noise signals We triggered on the big pulse in channel 5 and look at the amplified signal from Pixel 10 (small pulses disappear for some time after a big pulse ) Total 40 ms

  13. We also took data where we KNOW that we triggered on the pixel which was EARLIER in time and had the Amplifier on the one that “reacted” later. (sorry, but the data on the file was corrupted and Brian is trying to recover it now…) In this case, the later one did NOT have the small pulses either before or after the big pulse. Thus, pixels with small pulses are the ones which start the “cascade” and the other pixels which follow have been quiet just before (and after).

  14. Setup to look at the HV current on side walls of HPD (diode is isolated from this current path) ?? Cable capacitance HV 1G PC HPD HV gnd diode 10 M B Voltmeter 20 Mohm OR V RBX gnd Scope on 50 ohm

  15. HV current to Ground through ~5Mohm Previous measured at CERN

  16. Correlation between DC measured current through the side-walls of HPD and Noise

  17. Correlation between AC measured current through the side-walls of HPD and Large noise pulses (Pulse in the HV current is first) (negative so it is opposite from photo current)

  18. Correlation between AC measured current through the side-walls of HPD and Large noise pulses (Pulse in the HV current is first) (negative so it is opposite from photo current)

  19. Correlation between AC measured current through the side-walls of HPD and Large noise pulses (Pulse in the HV current is first) (negative so it is opposite from photo current)

  20. The worst HPD has his noise completely reduced at 4 Tesla (we did 18 hour test at 4 Tesla with no increase) (We are currently running the best one at 1.3 Tesla for a 1 day)

More Related