MPX-32D#

XIA’s MPX-32D is a 32-channel digitizer and modular pulse-processor that resides in a computer controlled PXI crate. Its primary function is to measure pulse-heights, i.e. event energies in an STJ system.

Relays#

By default, STJ Analog on-board relays are open. The STJ detectors are terminated with 1 MOhm resistors, and the preamplifier inputs are terminated with 10 kOhm resistors in parallel with 2 nF capacitors, i.e. a ‘dummy’ detector circuit. When the relays are closed/enabled, the preamplifier inputs are connected only to the HDDSUB-78 pins, i.e. to the STJ detectors, if present. We recommend first familiarizing yourself with the system by using the on-board pulser to generate an input signal before working with actual STJ detectors. Note that if the STJ detectors are not connected the HDDSUB-78 connector(s), the STJ Relay provides a convenient ‘low noise’ pulser setting: the pulser signal is much cleaner when the dummy detector circuit has been removed via the relay.

Name	Range	Description
AMRELAY	0 - 1	1 Connects the preamplifiers to the STJ detector. Defaults to 0

On-board Pulser#

The MPX-32D has a rudimentary built-in pulser circuit, which feeds a periodic signal to all preamplifier channels on the Analog Module. The signal is generated by a DAC on the MPX-32D which repeatedly cycles through 4K points of waveform data stored in RAM. It is quite useful for debugging and for exercising the data acquisition system.

The pulser’s default settings are a periodic pulse with a 1 us risetime and 5 µs decay time, at 1 kHz frequency. The following parameters can be used with the xiaSetParameter() and xiaGetParameter() to manage the pulser.

Name	Range	Description
PULSERENA	0 - 1	1 Enables the Pulser. Defaults to 0.
PULSERINV	0 - 1	Controls the polarity of the pulse waveform. It should be set to 0 or 1 such that pulses are positive in the ADC waveform. Defaults to 0.
PULSERATE	0 - 15	Controls the rate at which the DAC is updated: update `rate = 20 ns * 2^PULSERATE`. Note that this setting affects the rise time and decay time! With the default value 0, the waveform spans 80 µs, with a 1 µs risetime and 5 µs decay time. With PULSERATE=1, the waveform spans 160 µs, with a 2 µs risetime and 10 µs decay time, etc.
PULSEWAIT	0 - 255	ranging from 0 to 255, controls the time that the circuit waits before cycling back to the beginning of the waveform data, i.e. it can be used to reduce the count rate. Its units depend on PULSERATE: `wait time = 256 * update rate` as defined above. For example, with PULSERATE=0, the units are 5.12 µs.
PULSEGAIN	0 - 3	Controls the pulse amplitude, which is proportional to `2^PULSEGAIN`. Valid PULSEGAIN values ranges from 0 to 3.

Acquisition Parameters#

Use the following parameter names in conjunction with xiaSetAcquisitionValues(), xiaGetAcquisitionValues() and xiaRemoveAcquisitionValues().

Note

The following acquisition parameters all have a double type.

Name	Default	Description
baseline_average	256.0	Set the baseline average. Must be a power of 2, but if it isn’t then it is silently rounded.
bias_dac_enable	1.0	Toggle one of the last 8 bits of bank-level parameters BANKnCHANENA according to acquisition value setting for given channel: e.g. BANK1CHANENA=0x00FF –> Channels 8-15 enabled.
bias_dac_set_zero	0.0	Per-channel STJ Bias DAC offset value. Should be set after first scan, i.e. to the DAC value corresponding to the inflection point. Subsequent scans will correct the DAC value on a per-channel basis
bias_dac_zero	0.0	Sets the DAC zero point.
bias_scan_start_offset	0.0	The starting DAC value for a bias scan.
bias_scan_step_size	1.0	The size of each DAC step.
bias_scan_steps	4000.0	The number of DAC steps in the scan.
bias_scan_wait_time	10.0	The time in milliseconds that the FiPPI waits after communications with the Analog Module.
bias_set_dac	0.0	STJ Bias Voltage user setting
calibration_energy	5900.0	Sets the calibration energy. Forces a recalculation of the gain.
decay_time	10.0	Sets the decay time for RC-type preamplifier.
detector_polarity	1.0	Sets the detector polarity.
dynamic_range	5000.0	Sets the dynamic range composite value. The Dynamic Range acquisition value is the energy of an x-ray that would generate a pulse that spans 40% of the full-scale ADC input (1638 codes).
energy_threshold	0.0	Sets the energy threshold.
gap_time	0.240	Set the slow filter gap time.
list_mode_variant	16.0	Sets the list-mode variant in mapping mode.
mapping_mode	0.0	Enables disables mapping mode by switching to the appropriate firmware. Also used to indicate if mapping parameters should be downloaded to the hardware during startup.
maxwidth	1.0	Set the maximum width of the trigger filter pile-up inspection
mca_bin_width	1.0	Sets the MCA bin width, also known as eV/bin. Changing this value forces a recalculation of the gain.
minimum_gap_time	0.060	Set the minimum gap time for the slow filter.
num_map_pixels_per_buffer	0.0	Sets the number of scan points that should be in each buffer. This parameter is skipped if mapping mode is not currently active. Also, the value -1.0 means: Use the maximum size for points/buffer given the size of my spectra. All buffer size validation is done by the DSP code.
num_map_pixels	0.0	Sets the total number of scan points when the hardware is run in mapping mode. This parameter is skipped if mapping mode is not currently active. Setting the number of mapping points to 0.0 causes the mapping run to continue indefinitely.
number_mca_channels	2048.0	Set the number of MCA channels.
peak_interval_offset	0.0	Set the peak interval offset for the specified decimation.
peak_mode	1.0	Set peak mode for determining the energy from the energy filter output. PEAKMODE = 0: XIA_PEAK_SENSING_MODE The largest filter value from a given pulse will be used as the energy. PEAKMODE = 1: XIA_PEAK_SAMPLING_MODE. The energy filter value will be sampled at a specific time determined by the setting of PEAKSAM.
peak_sample_offset	0.0	Specify an optional peak sample time offset, in microseconds, that overrides the value specified in the FDD file.
peaking_time	1.0	Sets the peaking time. Returns an error if no FDD file is defined.
pmt_dynode_sum_threshold	0.0	Sets the PMT dynode sum threshold, which has a 16-bit range.
pmt_dynode_threshold	3000.0	Sets the PMT dynode threshold, which has a 14-bit range.
pmt_multiplicity_length	0.0	Sets the interval for PMT multiplicity with a 10-bit range.
pmt_multiplicity_requirement	0.0	The multiplity of PMT events to trigger the system. Ranges from 0 - 32.
pmt_trigger_mode	0.0	Sets the PMT trigger mode.
preamp_gain	100.0	Synchronizes the preamplifier gain in the Detector configuration with the preamp_gain acquisition value. Handel assumes that the preamplifier gain specified in the Detector configuration is correct and uses it to set the acquisition value preamp_gain. This routine does not cause the gain to be recalculated.
preamp_type	0.0	Sets the preamplifier type and synchronizes it.
preset_type	0.0	Set the preset run type. The allowed preset run types are defined in handel_constants.h.
preset_value	0.0	Set the preset run value. This value is interpreted differently depending on the preset run type, which means that this value must be set after setting the preset type. For fixed realtime/livetime: Specify in seconds. For count-based runs: Specify as counts.
reset_delay	10.0	Set the reset delay interval.
trace_trigger_enable	0.0	Enables trace triggering if non-zero.
trace_trigger_position	0.0	Sets the Pre-Trigger interval for trace acquisition in units of 16 ADC samples. For example, if `TRACELEN = 4096`, `TRACEPRETRIG = 128` will set the trigger point to the middle of the trace.
trace_trigger_type	0.0	Sets the trace triggering source according to the following map. 0 – Fast Peak 1 – Good Event 2 – Overflow Event 3 – Underflow Event 4 – ADC Rangebad 5 – NGATE edge 6 – Fast Pileup 7 – Slow Pileup
trigger_gap_time	0.0	Sets the trigger filter gap time.
trigger_peaking_time	0.100	Set the trigger filter peaking time
trigger_threshold	1000.0	Set the trigger threshold.

Run Data#

Use the following types in conjunction with xiaGetRunData().

Name	Type	Description
buffer_a	unsigned long*	Read mapping data from Buffer A. Requires mapping firmware.
buffer_b	unsigned long*	Read mapping data from Buffer B. Requires mapping firmware.
buffer_full_a	unsigned short	Checks to see if Buffer A is full. Requires the mapping mode firmware to be running.
buffer_full_b	unsigned short	Checks to see if Buffer B is full. Requires the mapping mode firmware to be running.
buffer_len	unsigned long	Calculates the size of the buffer, in 16-bit words, that will be returned by a call to `xiaGetRunData()` with the “buffer_a” “buffer_b” name argument. Requires mapping firmware.
buffer_overrun	unsigned short	Checks if a buffer overrun condition has been signaled. A value of 1 indicates a buffer overrun condition, while 0 indicates that the buffer has not been overrun. Requires mapping mode to be enabled.
current_pixel	unsigned long*	Gets the current mapping point. Requires mapping more firmware.
energy_livetime	double	Read the energy livetime from the board.
events_in_run	unsigned int	Get the events in run for the specified channel. This only returns the lower 32-bits of the events in run. For the complete 64-bit value, see `module_statistics`.
input_count_rate	double	Get the input count rate for the specified channel.
list_buffer_len_a	unsigned long	Calculates the size of the buffer, in 16-bit words, for Buffer A.
list_buffer_len_b	unsigned long	Calculates the size of the buffer, in 16-bit words, for Buffer B.
livetime	double	Read the energy livetime from the board.
mca_events	double	Gets the number of MCA events for the specified channel.
mca_length	unsigned int	Returns the current MCA spectrum length to the user
mca	unsigned long*	Get the MCA spectrum
module_mca	unsigned long*	Reads out the entire MCA block for the module that detChan is located in. This routine is an alternative to reading the MCA our individually for each channel. This routine assumes that all channels share the same size MCA.
module_statistics_2	double*	Returns the statistics for all channels on the module that detChan is a part of. Value is expected to be a double array with at least `statsPerChan * m->number_of_channels` elements. They are stored in the following format: [ch0_runtime, ch0_trigger_livetime, ch0_energy_livetime, ch0_triggers, ch0_events, ch0_icr, ch0_ocr, ch0_underflows, ch0_overflows, ..., ch3_runtime, etc.]
module_statistics	double*	Returns the statistics for all channels on the module that detChan is a part of. value is expected to be a double array with at least 28 elements. They are stored in the following format: [ch0_runtime, ch0_trigger_livetime, ch0_energy_livetime, ch0_triggers, ch0_events, ch0_icr, ch0_ocr, ..., ch3_runtime, etc.]
output_count_rate	double	Get the output count rate for the specified channel.
overflows	double	Returns the # of overflows in value.
realtime	double	Gets the runtime for the specified channel.
run_active	unsigned long	Get the run active status for the hardware.
runtime	double	Gets the runtime for the specified channel.
total_output_events	unsigned long	Get the events in run for the specified channel. This only returns the lower 32-bits of the events in run. For the complete 64-bit value, see `module_statistics`.
trigger_livetime	double	Get the trigger livetime for the specified channel.
triggers	double	Returns the # of triggers as a double in value.
underflows	double	Returns the # of underflows in value.

Gain Operations#

Use the following operations in conjunction with xiaGainOperation().

Name	Description
calibrate	Scale the analog gain according to given scale factor
scale_digital_gain	Calibrates the digital gain using the specified delta. Adjusts the digital gain by the inverse of the specified delta but doesn’t change the associated analog gain.

Board Operations#

Use the following operations in conjunction with xiaBoardOperation().

Name	Description
apply	Applies the current board settings.
buffer_done	Sets the specified buffer status to “done”. Requires mapping firmware. Returns an error if the specified buffer is not ‘a’ or ‘b’.
get_csr	Gets the Control Status Register.
get_cvr	Read the CPLD Version Register.
get_mcr	Gets the value of the Modem Control Register.
get_mfr	Get the Mapping Flag Register.
get_svr	Read the System FPGA Version Register.
mapping_pixel_next	Advances the mapping point to the next pixel. Requires mapping firmware. Requires mapping point control to be set to HOST, otherwise an error is returned.

Special Runs#

Run Type Listing#

Use the following run types with xiaDoSpecialRun().

Name	Read Data?	Type	Description
adc_trace	Yes	unsigned int*	Starts a run to collect ADC traces from all channels in the system.
adjust_offsets	No	unsigned int*	Tries to set all 32 channels Offset DACs such that their ADC average = value
begin_bias_scan	Yes	unsigned int*	Start steeping the STJ Bias DACs for all 32 channels through the user-specified range and acquires the average preamp output voltage value. The bias scan run will need to be stopped before other runs can proceed.
end_bias_scan	Yes	unsigned int*	Stops a Bias Scan currently in progress.
scale_digital_gain	No	unsigned int*	Calibrates the digital gain using the specified delta. Adjusts the digital gain by the inverse of the specified delta but doesn’t change the associated analog gain.
set_bias_dac	No	unsigned int*	Sets bias DACS for all channels in the module and Updates the STJDAC parameter value. Writes the value to the corresponding Bias DAC on the Analog Module.

Run Data Listing#

Name	Type	Description
adc_trace_length	unsigned long	Gets the ADC Trace length from the hardware. Getting the data stops the control task. If you do an ADC trace special run then you are required to read the data out to properly stop the run.
adc_trace	unsigned long*	Get the ADC trace from the board.
bias_scan_noise_length	unsigned long	Get the length of bias scan noise data
bias_scan_noise	unsigned long*	Get the bias scan noise data from the board.
bias_scan_trace_length	unsigned long	Get the length of bias scan trace data
bias_scan_trace	unsigned long*	Get the bias scan trace from the board.