THE Leasing Plans to Expand Your Laboratory Capabilities The Scientific Leasing Plans w i l l p r o v i d e t h e f u l l , i m m e d i a t e use of all n e w l a b o r a t o r y a p p a r a t u s , w h i l e b y - p a s s i n g large c a p i t a l expenditures. Any of the e q u i p m e n t r e q u i r e d for l a b o r a t o r y e x p a n s i o n — either a single i n s t r u m e n t or c o m p l e t e facilities — can be leased. • LOWEST RATES Rates u n d e r t h e Scientific Leasing Plans are at historic l o w s , even l o w e r t h a n t h o s e o f f e r e d u n d e r most m a n u f a c t u r e r ' s o w n lease terms. • FULL-SERVICE LEASING The Scientific Leasing Plans i n c l u d e useful a n t i obsolescence, trade-in, renewal and t e r m i n a t i o n o p t i o n s , w h i c h can be t a i l o r e d t o y o u r specific needs. A m a j o r p o r t i o n of r e n t a l p a y m e n t s can be c r e d i t e d t o w a r d later p u r c h a s e . W e w i l l w r i t e a " t r u e lease" so that q u a l i f i c a t i o n for r e i m b u r s e m e n t or d e d u c t i o n is assured.
scilease
Scientific Leasing Inc. F o u n d e r s T o w e r , F o u n d e r s Plaza E. H a r t f o r d , C o n n . 0 6 1 0 8 T e l e p h o n e (203) — 5 2 8 - 3 4 0 0
CIRCLE 1 8 7 O N READER SERVICE CARD
HERE'S THE LATEST IN LIGHT SCATTERING FROM C. N. WOOD . . NEW
DUOPHOTOMETER (WITH RATIO DIGITAL READOUT AND DIFFERENTIAL REFRACTOMETER ATTACHMENT).
It's all ours. It can be yours
for under $3,700 ί
Shown is the new Brice-type Model 5200 Duophotometer, with the DMR-300 Ratio Digital Readout meter (at $995.00) and RF-500 Dif ferential Refractometer (at $1,200.00). The 5200 features two light scattering systems and a design that permits the use of the ratio readout meter. The RF-500 is designed for direct use with the 5200, or with any Brice-type photometer. For more information about these instruments, or our other services, call or use the coupon.
G.N.WOOD mfg. co. 102 P e n n s T r a i l • N e w t o w n I n d u s t r i a l C o m m o n s R o u t e 332 • N e w t o w n , Pa. 18940 - (215) 968-4268 Gentlemen: Please send m e i n f o r m a tion about: Π M o n o and Duo p h o t o m e t e r s D Differential refracto m e t e r s • Photometer accessories Π I n s t r u m e n t services and parts.
NAME TITLE
DEPT.
ORGANIZATION ADDRESS CITY
STATE
ZIP
CIRCLE 2 1 9 O N READER SERVICE CARD 76 A
·
relative merits will change as improve ments are made in ion source intensities, vacuum capabilities, mass spectrometer resolutions, etc., and from one analyti cal problem to another. Thus, the potential user must closely examine his particular analytical problems and critically evaluate the two concepts before proceeding. It is also important for the potential user to understand that he may not be able to realize all combinations of the above capabilities simultaneously. Thus, an analytical situation which requires 1-jum lateral resolution, 10-40 A depth resolution, and a ppm sensitivity may prove too exacting even for an ion probe. Analytical Applications
• T E C H N I C A L EXPERTISE Scientific Leasing Inc. offers p r o f e s s i o n a l consultation on equipment evaluation and selection on request. W e w o u l d w e l c o m e the o p p o r t u n i t y to p r e p a r e specific proposals s u i t e d to y o u r needs. Ask the specialists — w e ' r e here t o serve y o u
A
Instrumentation
A N A L Y T I C A L C H E M I S T R Y , VOL. 4 4 , NO. 13, N O V E M B E R
1972
Although secondary ion mass spec trometry is a relatively new field, and the majority of the literature deals with instrumentation, the technique has been applied to a wide variety of sys tems. The applications can be roughly divided into surface studies, x,y microcharacterization, and in-depth pro filing. Surface Studies. Since the secondary ions are produced in the few atomic layers nearest the surface, the ion probe (referring to the general technique, not necessarily to the ion micropTobe) provides valuable surface character ization. The sampling depth can be controlled by varying the primary ion kinetic energy; all the elements as well as hydrocarbon type material can be detected ; isotopic labeling and exchange studies can be performed, and surface and bulk can be compared by sputter removal of the surface. In addition to the broad elemental coverage, the ion probe technique provides detection limits of 10~15 to 10~19 for most ele ments. On a relative basis this is of the order of 1 atom in a million. This can be 1 atom in a million (1 ppm atomic) comprising a surface contam inant or 1 ppm dispersed throughout a bulk region. Benninghoven and Loebach (4-, 5) have studied the kinetics and products of gassolid reactions by the "statical" mode of secondary ion mass analysis. Others have examined the impurities on metal, semiconductor, and mineral surfaces. Other workers have used the imaging capability to examine the x,y distri bution of surface contaminants on deposited thin films and tungsten sur faces. Hernandez and coworkers (17) used a high-resolution mass spectrom eter to study the hydrocarbon, oxide, and elemental ions sputtered from a surface. Although of preliminary na ture, this study indicates the value of high spectral resolution when molec ular ions are encountered during an analysis. Recently, Fogel (18) re-
