The initial measurement plan for the ePixM5kHz detector can be seen below and is divided into two sets according to the available cameras (initially a non-back-thinned detector and later a back-thinned detector). The non-back-thinned detector will have roughly 500um of non-responsive Si in front of the active sensor area, so this device will not be suitable for beamline testing.
Prototype delivery schedule:
The current estimated delivery schedule for the ePixM5kHz prototypes asre stated in the table below.
Table 1. Prototype delivery schedule for the ePixM5kHz prototypes.
| ePixM prototype version | delivery timeline | primary testing aim |
| non-backthinned | July | Understand running modes; Initial evaluation of performance parameters; evaluate if detector response changes as we change the switching point; Try and identify a way to determine gains and pedestals for both high and low gain modes |
| back-thinned | December | Full performance characterization; evaluation of detector timing; Linearity; switching behavior. Arrive at the calibration scheme. |
Measurement plans for the two prototypes:
Non-back-thinned testing:
Table 2. Initial measurement plan for the ePixM5kHz non-back-thinned prototype.
| Measurement | Stimuli | measurement aim | comments |
| Running modes | none | evaluate various readout schemes to see that they are running ok without dropped frames etc. when changing frame rates. | Assumes we have various potential run schemes, i.e. like run and daq trigger schemes for ePixHR. Require Dionisio or Lorenzo to know what running modes we have. |
| Pedestals | none | Check pedestal values. Evaluate the common mode noise behavior for these detectors. | If we can verify that changing the switching point does not change the detector response, then obtain a low pedestal by changing the switching point. If not, we have to figure out how we can determine the low-gain pedestal. |
| Temperature dependence of pedestals | none | Check how the magnitude of the pedestal shifts with the temperature | |
| Temporal stability of pedestals | none | Evaluate the pedestal drifts, especially at turn-on. | To check stabilization periods before data collection can happen. |
| Noise | none | Evaluate the noise level in both gains. | low gain evaluation assumes we can shift the switching point. |
| Temperature dependence of noise | none | Evaluate the noise as a function of temperature to know the impact of cooling | |
| Repeatable linearity behavior with varied switching point location | Charge injection | See if we can change the switching point and still have the same performance in linearity etc. | Needed in case we want to emulate Fixed gain mode operation; Will also show if we can determine the low gain and low pedestal by shifting the switching point. |
| Single photon gain (high gain) | Ag flourescence, Marietta | First evaluation of the gain. | Evaluate the gains and check if the gain ratios between low and high stay the same across the detector (single gain evaluation for gain calibration if possible, otherwise, not). |
| Single photon gain (low gain) | Ag flourescence, Marietta | First evaluation of the gain. | Assumes this can be evaluated by moving the switching point to always be in low. |
| Temperature performance under vacuum conditions | none | evaluate the thermal response when the detector is operating under vacuum condition; evaluate outgassing levels for the camera. | Requires the new vacuum setup to be ready. Evaluating the outgassing level will be dependent on the vacuum level we can get in the setup. |
Back-thinned testing:
Table 3. Initial measurement plan for the ePixM5kHz back-thinned prototype.
| Measurement | Stimuli | measurement aim | comments |
| Repeat above measurements | Varied | ||
| Timing behavior | LCLS beam (XPP/MFX) | Evaluate the timing windows, evaluate the transfer function; get an estimate of the filter response time. | |
| Linearity and switching behavior | LCLS beam (XPP/MFX) | Validating the linearity performance; evaluate the switching behavior; assessing the dynamic range; obtaining data for Gabriel's calibration functions if they work. | |
| Pulsed X-ray single photon response | LCLS beam (XPP/MFX) | More accurate determination of the single photon gain. | |
| Memory (ghosting) effects | LCLS beam (XPP/MFX) | To verify no ghosting effects are present and that we are fully resetting to baseline. |
Additional testing:
Table 4. Further testing needs for the ePixM5kHz detectors.
| Measurement | Stimuli | measurement aim | comments |
| Sensor QE | Determine the QE for the sensor at the relevant energies. | It will be strongly dependent on the entrance window for the intended energy range and will be essential to determine. Will have to work out a measurement plan with Chris Kenney. It will likely be done outside of SLAC, and should probably include measurement of the depth dependence of the resistivity and evaluation at the LBNL metrology beamline. |