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660 Dual 5-kV Detector Bias Supply Specifications Channels A and B are independent supplies. The specifications apply to either channel. PERFORMANCE BIAS VOLTAGE RANGES 0–5 kV, or 0–500 V, on separate outputs, with each output controlled by a common, 5-turn, direct-reading, precision potentiometer located on the front panel. BIAS VOLTAGE POLARITY Positive or negative. Internally selectable. Polarity indicated by front-panel LEDs whenever bin power is on.RATED OUTPUT CURRENT 0–100 µA. OUTPUT LINEARITY Within ±3% of dial setting from 10% to 100% of full range.TEMPERATURE SENSITIVITY OF OUTPUT VOLTAGE <±0.08%/°C through the 10 to 50°C operating range. VOLTAGE STABILITY <±0.1%/h variation in output voltage with constant temperature, constant load, and constant input voltages from the bin supply.NOISE AND RIPPLE <10 mV peak-to-peak from 5 Hz to 50 MHz. OUTPUT VOLTAGE RISE TIME Nominally 500 ms.INPUTS BIAS SHUTDOWN INPUT Rear-panel BNC connector accepts signals from warmup sensors in cooled germanium detectors. When a warmup is signalled, this input turns off the detector bias voltage in order to protect the preamplifier FET input. The ORTEC/TTL/BYPASS jumper selects the operating mode of the BIAS SHUTDOWN input for compatibility with the warmup sensor in the associated Ge detector. ORTEC Mode The input is compatible with the warmup sensor output on ORTEC germanium detectors. For added safety, an open or shorted coaxial cable on the BIAS SHUTDOWN input will also cause the supply to shut down. TTL Mode A source supplying >+2 V or an open circuit will allow the Model 660 to produce the full output voltage. A source supplying <+0.8 V and capable of sinking 700 µA will shut down the high voltage output.BYPASS MODE The BIAS SHUTDOWN input is rendered inactive, and cannot trigger a bias shutdown. OUTPUTS 0–5 kV Rear-panel SHV connector furnishes the adjusted output voltage in the 0 to 5-kV range through an output impedance of approximately 2 MW. A voltage foldback circuit protects the output against demands for excessive output current. Recovery from overload is automatic when the overload is eliminated. 0–500 V Rear-panel SHV connector furnishes the adjusted output voltage in the 0 to 500-V range through an output impedance of approximately 700 kW. A voltage foldback circuit protects the output against demands for excessive output current. Recovery from overload is automatic when the overload is eliminated.INDICATORS 0 kV–5 kV Front-panel, 10-segment, bar-graph display indicates actual output voltage at the 0–5 kV output. Each segment corresponds to a 0.5-kV increment in output voltage, starting with 0.5 kV to turn on the first segment, and ending with 5 kV to turn on the tenth segment. POS Front-panel LED is lit when the bin power is on, if the positive output polarity has been selected.NEG Front-panel LED is lit when the bin power is on, if the negative output polarity has been selected. ON Front-panel LED indicates when the output bias voltage is turned on. This LED turns off when the HV ON/OFF switch is turned off, the bin power is off, or the shutdown mode has been activated.OVERLOAD Front-panel LED turns on when the bias supply senses an excessive output current demanded by the external load. Under overload, the output voltage is reduced automatically until the output current is within tolerable limits. Recovery from overload is automatic when the overload is eliminated. SHUTDOWN Front-panel LED turns on when the shutdown mode has been activated to turn off the output voltage. The shutdown mode is activated by the appropriate signal level on the rear-panel, BIAS SHUTDOWN input, or whenever the bin power is turned off and on.CONTROLS 0–5 kV Front-panel, 5-turn, direct-reading, locking potentiometer with 500 dial divisions adjusts the output voltages simultaneously for the 0–500 V and the 0–5 kV outputs. HV ON/OFF Front-panel toggle switch turns the 0–500 V and the 0–5 kV outputs on or off. For added safety, the RESET push button must be pressed after turning the HV ON/OFF switch to the ON position, in order to turn on the output voltage. The output voltage will not turn on if a shutdown condition is present at the BIAS SHUTDOWN input.RESET Pressing this front-panel push-button switch enables the high voltage to turn on after the bin power has been turned on, the HV ON/OFF switch has been turned on, or the supply has been disabled by the BIAS SHUTDOWN input. If a shutdown condition is still present at the BIAS SHUTDOWN input, the RESET button will be ineffective. ORTEC/TTL/BYPASS Internal printed wiring board jumper selects the operating mode of the BIAS SHUTDOWN input for compatibility with the warmup sensor in the associated Ge detector. The ORTEC position is used for ORTEC detectors. The TTL position is for detectors employing TTL levels. The BYPASS position disables the BIAS SHUTDOWN input, but does not alter the function of the RESET button. The Model 660 is shipped with this jumper in the ORTEC mode.OUTPUT VOLTAGE POLARITY The output polarity is changed between positive and negative by changing the position of a daughter board in the module. ELECTRICAL AND MECHANICAL POWER REQUIREMENTS The Model 660 derives its power
from a NIM bin power supply. Required dc voltages and currents are: +24 V at 135 mA, +12 V
at 150 mA, –12 V at 100 mA, Net 0.90 kg (2.0 lb). Shipping 1.4 kg (3.0 lb). DIMENSIONS Standard single-width NIM module, 3.43 X 22.13 cm (1.35 X 8.714 in.) front panel per DOE/ER-0457T. ORDERING INFORMATION
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