BUY US SAVINGS BONDS - ACS Publications - American Chemical

May 18, 2012 - BUY U.S. SAVINGS BONDS. Anal. Chem. , 1963, 35 (11), pp 152A–152A. DOI: 10.1021/ac60204a854. Publication Date: October 1963. ACS Lega...
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NEW PRODUCTS

Stable to 0.01% . . . Indefinitely

NEW KEITHLEY

3500V D.C. SUPPLY The extreme stability of the Model 242 is not specified in hours. Now— over several months—you can per­ form extended duration measurem e n t s . C u m u l a t i v e d r i f t of t h i s regulated supply is prevented by a self-correcting feedback loop fea­ turing a temperature compensated zener diode reference, photo-chop­ per c o m p a r a t o r and wire wound sampling resistors. 300 V to 3500 V are delivered at 25 ma, with less than 1 mv combined ripple and n o i s e ideal for photo tube, photo multiplier and electron multiplier applications. Other specifications contributing to the outstanding value of the Keithley 242 are shown below.

N e w Laboratory Recorder

A new laboratory strip chart re­ corder, Model LS11A, is designed for laboratory and basic research person­ nel. The door of the recorder "disap­ pears" into the top of the recorder case where it is out of the way and not mis­ placed. Front panel mounted gain, damping, zero, recorder power, and chart controls permit easy adjustment. A five-speed dialomatic chart trans­ mission, plug-in range modules, "tabletop" notation platen, ball point pens, V 2 mv. minimum spans, and zero diode standardization are other standard fea­ tures. The laboratory recorder is also available as a dual pen recorder, Model LD11A, with both pens writing full scale. Westronics, Inc., 3605 McCart St., Fort Worth 10, Texas. 429

» o u t p u t : 300 t o 3,500 V at 25 m a in 1 v o l t s t e p s — p l u s , m i n u s , or f l o a t i n g t o 4500 V > stability: 0 . 0 1 % i n d e f i n i t e l y , minute warm-up

after

30

• accuracy: ± 0 . 1 % • ripple and noise: Less t h a n 1.0 m i l l i ­ volt r m s ' line r e g u l a t i o n : 0.005% for 10% c h a n g e in l i n e v o l t a g e • load r e g u l a t i o n : 0.005% f r o m z e r o t o full load 1

o v e r l o a d p r o t e c t i o n : A u t o m a t i c dis­ c o n n e c t if c u r r e n t e x c e e d s 27 m a

• price: $850

Other Regulated DC Supplies M o d e l 241, 0-1000 V, 0.05% a c c u r a c y

$800

M o d e l 240, 0-1000 V, 1.0% a c c u r a c y

$345

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K KEITHLEY INSTRUMENTS

12415 Euclid Avenue · Cleveland 6, Ohio Circle No. 190 on Readers' Service Card

152 A

·

ANALYTICAL CHEMISTRY

The carbon dating instrument shown permits high sensitivity measure­ ments of carbon-14 in the naturally occurring levels. The instrument works on the principle of conversion of any carbon-containing compound into benzene for radioactivity meas­ urement in a liquid scintillation spec­ trometer. Sample conversion is to C 0 2 - > Li 2 C 2 - » C 2 H 2 - » C e H e , with an overall chemical efficiency of ap­ proximately 5 0 % . The final step is done by a catalyst which is activated by the user, or which can be pur­ chased already activated from the manufacturer. Very low levels of H 3 can also be measured through label­ ing of the benzene molecules. This is done by hydrating commercial car­ bide with the water sample to be counted, converting the resulting acetylene to benzene for measure­ ment. Packard Instrument Co., Inc., Box 4 2 8 , La Grange, III. 430

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BUY U.S. SAVINGS BONDS This advertising is donated by The Advertising Council and this magazine.