The Model 3412 16-channel CAMAC ECL discriminator is a high performance unit. It has 16 inputs which accommodate a wide range of input signal levels and operates with input rates up to 200 MHz. The 3412 has differential ECL logic outputs (which offer noise immunity). These outputs are compatible with LeCroy's ECLine family of CAMAC modules including the following: Model 2366 Universal Logic Module, Model 4448 Coincidence Register, Model 4508 Programmable Lookup Unit, Model 4516 Logic Unit, Model 4532 Majority Logic Unit and many more. Descriptions and specifications of the above units can be found on their own separate data sheets.
The 3412 uses 16 of LeCroy's new, state-of-the-art, monolithic integrated circuits, MDC100, which offer a Double Pulse Resolution (DPR) of 4 nsec and output widths from <5 nsec to > 100 nsec. The MDC100 also features built-in hysteresis which eliminates multiple pulsing on slow input transitions.
The 3412 accepts negative-going pulses via front- panel Lemo connectors. Threshold ranges from -10 mV to -1.023 V for the 3412, and from -15 mV to -1.023 V for the 3412E. The threshold can be adjusted remotely by CAMAC control or locally by a front-panel potentiometer. A monitor point is provided to permit accurate measurement of the threshold with a voltmeter.
Each channel has two separate differential ECL outputs. The output width can be adjusted from <5 nsec to > 100 nsec. Each channel can be masked by either externally applied signals from the rear-panel veto connector, or by CAMAC control. In Local mode, only the external inhibit signals will be active.
Three discriminator modes of operation are built into the 3412: Non-updating, Updating and Burst Guard. These modes can be selected by CAMAC control in Remote or by a side-panel DIP switch in Local.
A current sum output is provided by a rear-panel Lemo. Each discriminator that is active provides 1 mA of current to an external 50 n load.
A built-in test feature simulates an input signal for each channel upon receipt of either an F(25) command or a NIM level signal applied to the test input connector. This permits rapid, simultaneous testing of all enabled discriminator channels.
INPUT
Signal Inputs: Sixteen inputs via Lemo front-panel connectors, 50
Ohm+/-2%. Protected to+2 A for 0.5 usec clamping at +/-5 V.
Reflections < 5% for input pulses of 2 nsec rise time for
amplitudes up to 1 V; input offset voltage typically +/-3 mV.
Test Input: One Lemo connector on front panel, 50 Ohm +/-2%, triggers
all enabled channels. Requires NIM level signal (< -600 mV).
Minimum width, 3 nsec. Maximum rate, 20 MHz. Rise time < 2
nsec.
Veto-Input: One Lemo front-panel connector, 50 Ohm +/-2%. Permits
simultaneous fast inhibiting of all chan- nels. Requires NIM level
signals. Direct coupled. Must precede input signal by approximately 6
nsec and overlap its leading edge in Update mode or overlap complete
input signal in Burst Guard mode. Minimum duration, 8 nsec.
Individual Vetos (masking): 16 differential (100 Ohm twisted pairs)
ECL lines (Emitter ORed with CAMAC mask) inhibit selected
discriminator channels. Differen- tial True signals inhibit channel;
unconnected inputs go to False or uninhibited state; 34-pin
rear-panel connector.
THRESHOLD
General: Threshold setting common to all channels; front-panel
screwdriver adjustment in local mode or through 12-bit DAC in remote
mode (0.25 mV resolu- tion). Stability better than 0.3%/'C to 60'C
operating temperature. Threshold monitor point on front panel has
10:1 ratio of monitor voltage to actual voltage +/-5%.
Hysteresis: Approximately 5 mV for the 3412, 6 mV for the 3412E.
MODEL 3412
Setting: -10 mV to -1.023 V+(5% or 2 mV whichever is greater) minimum usable threshold is -8 mV+2 mV, channel to channel.
Note: VT = (-X/4095)(1024)-10mv
where VT = Threshold Voltage in (mV)
X = DAC Counts (0-4095)
MODEL 3412E
Setting: -15 mV to -1.023 V+/-(5% or 3 mV whichever is greater)
minimum usable threshold is -12 mV +/-3 mV, channel to channel.
Note: VT = (-X/4095)(1024) -- 15 mV
where VT and X are same as above.
OUTPUT
Discriminator Outputs: Two separate outputs per channel. ECL level
(-0.8, -1.7 V) into 100 ohm twisted- pair. Duration: < 5 nsec to
> 100 nsec in the Non- updating mode, continuously variable via
screwdriver control in the Local mode or by CAMAC control in Remote
mode. Common to all channels. Rise times and fall times < 2 nsec.
Width stability better than 0.3%/'C maximum.
Output Width Matching: +/-10% channel to channel.
Current Sum Outputs: Rear-panel Lemo connector; high impedance
current source; generates a current proportional to the input
multiplicity at the rate of -1 mA+/-10% per hit (-50 mV per hit into
a 50 ohm load); for output widths > 8 nsec*.
Output Operation Modes: Non-updating or Updating with or without
Burst Guard. The modes are selectable by a side-panel DIP switch in
Local mode or CAMAC control in Remote mode.
GENERAL
Maximum Rate: 200 MHz guaranteed.
Mode Select: Local mode and programmable mode selectable via CAMAC
command, or front panel push- button to enable Local mode.
LED Indicators: Remote mode selected (RMT) and CAMAC accessed
(N).
Double Pulse Resolution: 5 nsec, typical.
Time Slewing: Less than 500 psec for input ampli- tudes from 2x to
20x over threshold.
Input-Output Delay: < 8 nsec. Delay matching better than +/-950
psec.
Test-Output Delay: < 11 nsec typical, 13 nsec maximum.
Mode Switch: A side-panel DIP switch enables Non- updating, Updating
or Burst Guard and Extended Width operation for all channels. A
front-panel LED is lit when Updating operation is selected.
Remote to Local Switch: Recessed front panel forces unit from remote
to Local mode.
Packaging: RF-shielded, CAMAC #1 module.
Power Requirements: 2.5 A at -6 V; 1.4 A at +6 V; 30 mA at -24 V; 60
mA at +24 V.
Environment: Proper operation of the 3412 requires +25'C air intake
with sufficient airflow to maintain temperature rise of exhaust air
to < 20'C.
CAMAC COMMANDS I: Inhibits all discriminator channels. Z-S2: Clears all registers. Sets Local Remote to Local. C-S2: Clears all registers. Sets Local Remote to Local. X: Generated for all valid functions. Q: Generated if a function can be executed. CAMAC FUNCTION CODES F(0)-A(0) N: Reads mask (R1-R16). F(0)-A(1) N: Reads Threshold (R1-R12). F(0)-A(2) N: Reads Width (R1-R12). F(0)-A(3) N: Reads Updating Status (R1). 1 = Updating, 0 = Non-updating. F(0)-A(3) N: Reads Burst Guard (R2); 1 = Burst Guard On; 0 = No Burst Guard. F(16)-A(0) N S1: Writes Mask (W1-W16). F(16)-A(1) N S1: Writes Threshold (W1-W12). F(16)-A(2) N S1: Writes Width (W1-W12). F(16)-A(3) N S1: Sets Updating Mode (W1). 1 = Updating, 0 = Non-updating. F(16)-A(3) N S1: Sets Burst Guard (W2). 1 = Burst Guard; 0 = No Burst Guard. F(24)-A(0) N S1: Set to Local mode. F(25)-A(0) N S1: Test. F(26)-A(0) N S1: Set to Remote mode. F(27)-A(0) N S1: Checks Remote/Local mode. Q = 1 only if in Remote mode. Note: The 3412 will power up in the Local mode. In Local mode the user can set the threshold and width by front-panel pots, the mode of the discriminator (Updating and Burst Guard) can be set by a side-panel DIP switch.