wxGUI Pulse Display
Scintillator pulse shape capture.
wxGUI Pulse Overlay
Overlay of 20 scintillator pulses.
wxGUI Pulse Acquistion
| Button functions |
|---|
| New | Start a fresh acquisition. |
| Save | Save pulse data to file. |
Figure Only /
Show Ctrl | Hide the display controls to save screen space. |
Action buttons on the pulse display.
wxGUI Pulse Acquistion
| Display controls |
|---|
| num_pulses | Number of pulses to acquire and overlay. If num_pulse > 20, data will automatically be saved to file. |
| t_min, t_max | Region used in the pulse analysis (in seconds). The analysis computes pulse shape parameters (height, width, etc) and the DC-baseline (average and noise). |
| comment | A comment to be added to the saved data. |
Display controls for the pulse acquisition.
wxGUI Sample vs Background
Sample, background and difference spectrum
Shown here: a 60cps background with a 3cps Cs-137 souce added to the sample.
wxGUI Background
wxGUI Sample vs Background
wxGUI Sample vs Background
The MCA-1000 series devices can simultaneously store a background and a sample spectrum. If arm_ctrl["user"]["sample_alarm"] is set to 1, the MCA will compute the difference spectrum and calculate the probability that the measured sample count rate was caused by the previously measured background.
The Sample vs Background display turns the probability limits into a logarithmic signal strength: S=-log10(P). For example a strength of 4 means that the probability is 10-4.
| Button functions |
|---|
| Toggle Alarm | Toggle arm_ctrl["user"]["sample_alarm"] between 1 and 0. |
| Sample | Erase old sample histogram and counting data and start a fresh acquisition. |
| Background | Erase old background histogram and counting data and start a fresh acquisition. |
| Refresh | Reload currently active histogram and counting data from MCA. |
| Fit | Apply a Gauss fit to the fit_xmin, fit_xmax region. |
| Save | Save all three histograms and counting data sets to file. |
Figure Only /
Show Ctrl | Hide the display controls to save screen space. |
Action buttons on the sample vs background display.
wxGUI Sample vs Background
| Display controls |
|---|
| num_bins | Number of histogram bins to display. |
| fit_xmin, fit_xmax | Region used for the exponential fit, in micro-seconds. |
| comment | A comment to be added to the saved data. |
Display controls for the arrival time histogram.
wxGUI Arrival Times
Logarithmic display of arrival time histogram
wxGUI Arrival Times after 1s
Arrival time histogram at 1500cps after only 1s.
Arrival time histogram at 1500cps after 10s.
wxGUI Arrival Times
Randomly arriving scintillator pulses will have an exponential distribution of the time between events. The MCA-1000 and some counters can measure and histogram the arrival times. This provides an accurate count rate measurement, independent of any assumptions about the MCA dead time per event.
| Button functions |
|---|
| New | Erase old histogram and counting data and start a fresh acquisition. |
| Refresh | Reload histogram and counting data from MCA. |
| Fit | Apply an exponential fit to the fit_xmin, fit_xmax region. |
| Save | Save arrival histogram to file. |
Action buttons on the pulse display.
wxGUI Arrival Times
| Display controls |
|---|
| fit_xmin, fit_xmax | Region used for the exponential fit, in micro-seconds. |
| comment | A comment to be added to the saved data. |
Display controls for the arrival time histogram.
wxGUI Two-channel logger
Sample signal strength increasing with counting time.
The new sample acquisition started at t=18s. At t=34s enough statistics had been acquired to say with a 1:10000 certainty that the sample is more radioactive than the background.
wxGUI Two-channel logger
The MCA-1000 and the Counters have a built-in two-channel logger. Any two parameters shown in arm_status can be logged with a 1022 sample logging depth. The dwell time can be set in steps of 50ms from 50ms to 255*0.05s=12.75s.
The purpose of the logger is to record transient phenomena that are too fast to be reliably recorded through a series of frequent client data reads.
Counts per 100ms and generated alarm during walk by past a portal monitor.
Controls
| Button functions |
|---|
| New | Erase old logger data and start a fresh acquisition. |
| Read | Read current logger data from the MCA or Counter. |
| Save | Save logger data to file. |
Figure Only /
Show Ctrl | Hide the display controls to save screen space. |
Action buttons on the pulse display.
| Display controls |
|---|
| parameter_1, parameter_2 | Index of the parameter in thearm_status["registers"] array; cf list of computed indices in table below. |
| draw_line | Set to 1 to draw a line between data points. |
| draw_item | Select which data to display. |
| comment | A comment to be added to the saved data. |
Display controls for the arrival time histogram.
| Computed logger channels. |
|---|
| 128 | Scintillator pulses during the logger dwell time. |
| 129 | Net counts entered into the Portal Monitor Alarm system (time slices) |
| 130 | Portal Monitor background probability |
| 131 | Sample background probability |
Computed logger channels.
