The Model 593.2 is the most sensitive tritium in air monitor that we offer and is designed for accurately measuring ultra-low levels of airborne tritium through the use of a dual measurement system with automatic solenoid valve operation to direct the sample to the appropriate detector. A pair of 2L ionization chamber detectors are utilized for measuring the tritium when levels exceed 1 MBq/m3 in order to provide a fast response time of 10 minutes while instrument air is used as the purge gas for the Nafion dryer to save on P-10 usage. The compensation ionization chamber is used to measure and subtract gamma and filtered radioactive gases from the Nafion dryer in a differential mode. When tritium levels are <1 MBq/m3, P-10 is used as the purge and counting gas and the sample is directed to the proportional counting detector with a typical response time of 40 minutes to reach 90% of the final value.
Model 593.2 is sensitive to only tritium, a Nafion dryer (selectively permeable membrane) is used to isolate tritium oxide before measurement; all other sample constituents, including pollutants, radioisotopes (i.e., noble gases), aerosols, and particulates are removed and eliminated prior to measurement. For measuring total tritium (HT + HTO), a catalytic oxidizer can be included to convert elemental tritium to tritium oxide. The 593.2 features a large, color touch-screen LCD display and is housed inside an industrial IP-54, NEMA-13 rated cabinet with a polycarbonate window door and key locking latch on the door. Custom software allows you to view configure alarm settings, generate graphs, view trends, monitor and display malfunction, and alert conditions, and log all data and events.
The 593.2 uses both electronic signal processing (analyzing pulse height and duration) and a second, sealed proportional counter to eliminate the effects from external gamma fields. 1” lead shielding around the counter tubes further reduces background gamma and improves the statistical signal to noise ratio to enhance sensitivity.
This instrument requires a supply of instrument air and P-10 gas for the operation of the proportional counting detectors. Suggested P-10 cylinder size: 8.5 m3 (300 ft3).
|RANGE||a) 1 kBq/m3 to 2,000 MBq/m3|
b) 0.01 μCi/m3 to 19,999 μCi/m3
|RESOLUTION||0.1 kBq/m3 (0.003 μCi/m3)|
|SENSITIVITY||1 kBq/m3 (0.01 μCi/m3)|
|DISPLAY||10” Color Touch-Screen LCD|
|TIME RESPONSE||Low level measurement (1 kBq/m3 to 10 MBq/m3): 40 minutes to reach 90% of final value|
High level measurement (0.1 to 2,000 MBq/m3): 10 minutes to reach 90% of final value
|MEASUREMENT, INTERFACE OUTPUTS||i) 0 – 10 V, linear|
|PROPORTIONAL COUNTERS||Balanced pair of copper clad acrylic counter tubes, 1.5 liters total volume each, surrounded by 1” of lead shielding|
|IONIZATION CHAMBER||Dual 2L ionization chambers on one axis with sample flow through both for differential tritium measurement|
|ALARMS, MALFUNCTION||i) instrument air low flow|
ii) P-10 gas low
iii) chamber or power supply malfunction
iv) oxidizer temperature
v) low sample flow
|ALERT CONDITIONS||Background high level, tritium loss of signal, background loss of signal, tritium low counts, and background low counts|
|ALARM CONDITIONS||i) Tritium alert level|
ii) Tritium high level
|ALARM INTERFACE||i) fail safe relay closures|
|COUNTER GAS||P – 10 (90% Argon, 10% Methane)|
Supply pressure: 10-14 PSIG (69-97 KPa)
Usage: 400cc per minute @ atmospheric pressure
|SAMPLE FLOW SYSTEM||Brushless Dual Bearing Diaphragm Pump, flow rate 5 lpm typical|
|FLOW METER||P-10 Gas Flow & Instrument Air Flow Adjustable 0-500 cc/min, Manual set-point 400cc/min|
|MASS FLOW METER||Sample Flow, range 0-250 cc/min, electronically controlled set-point 200cc/min|
|SIZE||70.9” [1800mm] High x 23.3” [600mm] Wide x 23.3” [600mm] Deep floor mounted painted steel enclosure with polycarbonate window door and key locking latch on door. Rear hinged door and hinged side panels. IP-54, NEMA 13 Rated|
|WEIGHT||630 lbs (286 kg)|
|POWER||115/230V 50/60 Hz, 100 W max.|