Trying to replicate what a pulsed wide-beam source from the gallary does to camera with lab-bench equipment
Ideas
Testing
- NSUB Capacitance vs. Bias-Voltage???
Hardware
- SA-261-101-30-C00 (SEDA) (Sub-Assembly Source meter 5mA current limiter)
- SD-261-101-30-C00 (SEDA) (Sub-Circuit Source meter 5mA current limiter)
- PC-144-174-04-R0 (Fast Pulse Test Board)
Q&A
- What is the amplitude of the voltage pulse required to emulate beam-line?
- Clue: Not sure, but output voltage capabilities of DAC might give a clue also need to make sure not over-driving till break down
- How much charge do we expect tripping to happen at?
- "medium -> low is 2400 keV/pixel so 6.6*10**5 electrons/pixel. High->low is probably 1/3 that, but we don't use AHL currently, so I'd focus on AML if possible." – Philp Hart
- Beamline Pulse duration?
- "The pulse is a delta function - 50 femtoseconds or less, typically. The pair creation energy in Si is about 3.6 eV." – Philp Hart
- What is typical bias voltage applied on Detector Bias line to reverse bias the substrate?
- On slide 5 of ePix Readout System (gdrv) it says ~100[V] is this correct (shouldn't it be negative???)?
- NO! ITS AN NSUB
- On slide 5 of ePix Readout System (gdrv) it says ~100[V] is this correct (shouldn't it be negative???)?
- At this bias or some known bias voltage what is the expected substrate capacitance for a entire sensor (there are asic 4 in parallel)?
- "The detector capacitance per pixel should be around 150fF" – Bojan
- An ASIC is ~2x2[cm^2] at 176x192 pixels
- Total Number of pixels = 2x (176x192) x 2 = 352x384 = 135168 → 20.3nF
- When the beam hits the substrate, which way does the current flow (in/out of pixel front-end) or (assuming substrate is negatively biased) that the current being drawn from the pixel front-end is less/more negative when a pulse hits (positive/negative voltage pulse)?
- "It's for sure positive (not sure the actual voltage value). The baseline of the preamplifier is around 2V and it swings down when there is a signal."–Bojan
- What is the capacitance vs. bias curve of substrate?
- See testing section above