DESCRIPTION
DESCRIPTION
The model 7106 is a high-performance, 16 channel leading edge discriminator packaged in a single width CAMAC module. The most commonly asked for features have been designed into this discrimintor, making it an extremely versatile instrument.
The 7106 threshold is variable from -10 mV to -1.033 Volts by either a front panel control when in LOCAL mode, or via CAMAC when in REMOTE mode. The module always powers up in the LOCAL mode which helps eliminate the possibility of having all the thresholds going to minimum, sometimes causing damage to sensitive detectors if the trigger rate were too high. The threshold can be measured at the front panel test point (voltage is ten times threshold) or may be read via CAMAC (10-bit ADC with 1 mV resolution) independent of the MODE of the module.
A linear summed output provides a -1 mA current for each channel that is active. By feeding the SUM output into a discriminator, the user can perform prompt majority logic decisions, selecting events based upon a minimum or maximum number of channels fired, often greatly simplifying the logic required for complex triggers.
Inhibiting of the discriminator can be performed by applying a NIM signal to the VETO input connector, which inhibits all 16 channels simultaneously. Individual channels may be masked (REMOTE mode only) by writing into the intemal mask register via CAMAC. The mask register is disabled whenever the 7106 is in LOCAL mode.
The outputs can be retimed by applying a NIM signal to the SYNC input connector. The state of all channels will be held for the duration of the SYNC input signal. This feature allows the channel profile to be maintained while an event trigger processor captures the profile. In addition to freezing the outputs of the discriminator, the SYNC signal also causes the states of all outputs to be transferred into an internal 16-bit register for subsequent readout via CAMAC. The CAMAC read of the DATA LATCH returns (in addition to 16-bits of data) a Q=1 response, if and only if, a SYNC signal has occurred since the last read of the DATA LATCH. A Q=0 indicates that the DATA LATCH has not been updated since the last CAMAC read.
The 7106 can be used as an updating or Time-Over-Threshold (TOT) discriminator as selected with the front panel Update/TOT switch. The updating output is variable from 4.5 nsec to 110 nSec and will be extended should an input occur while the output is active. In the TOT mode, the output will equal the Time-Over-Threshold of the input or the Preset output duration, whichever is longer. A special TOT mode can be enabled (via internal jumper, one per channel) such that the output duration will equal 5 nSec or the Time-Over-Threshold of the channel, whichever is longer. A mixture of both types of TOT mode can be used within one module. A front panel LED is on when the UPDATE mode is selected. Connecting a NIM signal (5 nSec minimum duration to the TEST input connector will cause those channels not MASKED off to be triggered just as if a normal input signal exceeded the threshold of each channel. A CAMAC command has been included (F25) which when executed will cause all channels not MASKED off to be triggered in the same manner as the TEST input. There is one difference, the CAMAC command (F25) will only execute if the 7106 is in the REMOTE mode. The Q response to the F25 command will indicate whether or not the test pulse was generated. Q=1 means it was. The TEST feature, used in conjunction with the MASK register, allows user defined output patterns to be generated for testing complex triggers.
The front panel switch labeled CAMAC/LOCAL determines which features are programmable. When the switch is in the LOCAL position, CAMAC can only monitor the 7106; i.e., read THRESHOLD voltage and DATA LATCH contents. While in LOCAL the effects of the MASK register and internal Threshold DAC are disabled, but both registers can still be written into and read out. Switching between LOCAL and CAMAC will not alter the contents of any internal register. When the front panel switch is in the CAMAC position, the mode of the 7106 (LOCAL or REMOTE) is programmable via CAMAC. When programmed into the REMOTE mode, the THRESHOLD is controlled by an internal 10-bit DAC, and the MASK register is enabled. CAMAC can also force the 7106 into the LOCAL mode which is identical to positioning the switch to LOCAL with one exception and that is that CAMAC can force the unit back into the REMOTE mode (only if the switch is in CAMAC). A front panel LED is on when the 7106 is in the REMOTE mode. Page 2