MANUAL LIQUID SCINTILLATION
COUNTING SYSTEM

Model # SSS-22

FEATURES:

* HIGH SENSATIVITY H$^{\textrm{3}}$, C$^{\textrm{14}}$, ALL BETA
  EMITTERS AND LOW ENERGY GAMMA EMITTERS

* DUAL PM TUBE DESIGN

APPLICATION: The SSS-22 Manual Liquid Scintillation 
Counting System accurately quantitatively measure 
Carbon-14, Tritium and other radioactive labels.
 
SYSTEM DESCRIPTION:
 <Graphic file:sss-22img-02.ps>

 Figure 1: SSS-22

Measuring Priciple: The most sensative method of 
detecting and quantitating beta emitting isotopes is to 
intimately mix the sample with liquid scintillation 
fluor and count each individual scintillation event 
with a dual photomultiplier coincidence counter. 
Followed by an energy analyzer which further selects 
the pulses and delivers the true signal. Hard copy 
printer is optional.

Detection cell optically coupled to two selected 
photomultiplier tubes which count in coincidence mode. 
Coincidence counting eliminates photo-cathode noise 
pulses, that are always present in any one-PM-tube 
system. Extremely good figure of merit for low energy 
betas such as H$^{\textrm{3}}$ and C$^{\textrm{14}}$ are thus achieved.

GAMMA BACKGROUND RADIATION REJECTION FEATURES:

* Lead shielding around detector

* Energy Analyzing window rejects pulses with energies 
  outside the window setting

COUNTING ASSEMBLY FEATURES:

* Excellent repeatability

* Fully light tight system

* Fail safe interlock to protect PM tubes

PM TUBE AND PRE-AMP NOISE IS ELIMINATED BY THESE FEATURES:

* Coincidence counting - dual PM Tubes

* High quality PM tubes and preamps

* Fully adjustable energy analyzer window rejects low 
  energy pulse

Settable window can be set for any isotope. C$^{\textrm{14}}$ window 
can be set for maximum responce, or can be set to 
exclude Tritium.
 
READOUT IN PERCENT OR IN COUNTS

Preset count and preset time functions allow direct 
comparison of standard and sample: The SSS-22 allows 
readout of sample activity directly as a percent of the 
standard, in counts/sec or counts/minute. Optionally, 
gamma ray counting is achieved by inserting and 
optically coupling an Na(Tl) scintillation well crystal 
between the PM tubes.

T$_{\textrm{A}}$                                   TECHNICAL ASSOCIATES                                   
------------------------------------------------------------------------------------------
  7051 ETON AVENUE * CANOGA PARK, CA 91303 TELEPHONE (818) 883-7043 * FAX(818) 883-6103   


$Revision: 1.3 $

MANUAL LIQUID SCINTILLATION
COUNTING SYSTEM

Model # SSS-22

DATA ANALYSIS AND PRESENTATION

Scintillation counts which are detected simultaniously 
by both PM tubes are processed by a fully adjustable 
single channel analyzer which is centered on the energy 
peak of the isotope being measured. This deletes both 
higher energy pulses from background radiation and 
lower energy counts from the PM tube or circuit noise. 
The pulses are then fed to a digital scaler and 
Optional digital printer. (Thus allows long count times 
for measurement of very minute samples as well as 
completely elimination artifacts caused by ratemeter 
time constants.) Built-in RS-232 serial input of most 
computers. Optional Win-wedge data logging software.

SPECIFICATIONS:

Tritium Efficientcy: In excess of 60% for all systems.

C-14 Efficientcy: Typically 90%.

For Dual Channel System: C$^{\textrm{14}}$ Efficiency: 15% when H$^{\textrm{3}}$ window 
is set for 50% H$^{\textrm{3}}$ efficiency.

Count Times: 1 sec thru 99,999 sec, in 1 sec increments.

Voltage: 0-2000 Volts - 2 fully independant HV 
supplies, individually settable.

Readout: Digital - 5 digit plus overflow.

Power: 110VAC, 60 Hz (220V 50 Hz Optional).

Dimensions: Electronics console 21"W x 18" x 11"H. 
Detector enclosure 18" x 6" x 6".

Weight: 45lbs.

Shipping Weight: 65lbs.

Sample Size: Accepts standard Liquid Scintillation vials 
up to 1.1" dia. x 2 1/2"H.

Scintillation Fluors: Accepts most scintillation fluors.

Options: Digital Printer Model MPM-5.
Gamma Well Counter Crystal, NaI(Tl).

Calibrated Sources: Set of 3 Calibrated standards, C$^{\textrm{14}}$, H$^{\textrm{3}}$ 
and background, all unquenched in sealed vials.

<Graphic file:sss-33img2-02.ps>

Detector for SSS-22

T$_{\textrm{A}}$                                   TECHNICAL ASSOCIATES                                   
------------------------------------------------------------------------------------------
  7051 ETON AVENUE * CANOGA PARK, CA 91303 TELEPHONE (818) 883-7043 * FAX(818) 883-6103   


$Revision: 1.3 $