NEW! Multi-Purpose Scintillation Detector With Optional Accessories... c
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NEW BOOKS standable to the practicing chemist. Some shortcoming's in bibliography may be excused in this type of book, as may be its rather high prevalence of typo graphical errors. On the other hand, inclusion of the discussion which fol lowed each paper is one of the book's valuable features, for this provides a good index to trends of current thinking. All in all, the book is to be highly recommended.
Systematic Identification of Organic Compounds. R. L. Shriner, R. C.
Fuson, and D. Y. Curtin. 4th edition, ix + 426 pp. John Wiley and Sons, Inc., 440 Fourth Ave., New York, Ν. Υ., 1956. $6.00. Reviewed by C. W. GOULD, General Electric Co.,
Schenectady, Ν. Υ.
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Optional accessories include (A) %", (B) Vz", and (C) well scintilla tion crystals. Large lead collimator (D) provides exceptional side shielding, accepts 20° flat field collimator (E) or special focusing collimator (F). Alpha and beta phosphors (G) are interchangeable with standard 1 " crystal,
FOR USE WITH STANDARD SCALERS OR GAMMA RAY SPECTROMETERS Standard probe is quickly converted into a scintillation well counter by changing crystals and adding Inexpensive base and shielding.
Easily accessible switch in housing per mits changing from preamplifier output for scaler or rate meter use to cathode follower output for gamma ray spec trometry work.
Nuclear-Chicago's new Model DS-5 is the first completely self-contained scintillation detector designed for basic counting or for the revolu tionary techniques of gamma ray spectrometry, "pin-point" depth focusing, or source scanning. This is a unique instrument—providing un matched performance for your present require ments and quickly convertible to the many new applications you'll face in the future. T h e most advanced scintillation counter o n t h e market, the new DS-5 is inexpensive, reliable and easy t o operate. Write today for detailed specifications.
S P E C I F I C A T I O N S Crystal—Normally supplied with 1" χ 1" N a l ( T l ) crys tal. Other size crystals and phosphors optional. 1" χ l'A" lucite light pipe. Crystal can be exposed directly in path of radiation. Phototube — DuMont 6292 protected by a magnetic shield. Shielding—Internal Ji * χ 3" lead ring. External lead nose provides 1γΛ" or more of lead at sides. Acceptance angle at rear is less than 25°. Amplifier—New one-tube feedback amplifier provides gain of two and cathode follower positive output for spectrometer use; gain of 10 with negative output for normal use. Band width sufficient for 1 microsecond resolution. Provides pulse height limiting for spectrom eter use. Operation (with 1"χ 1" crystal)— Plateau: 250 volts; 2% slope/100 volts. Background: Crystal exposed—1250 cpm; with lead nose—160 cpm; with additional collimation—95 cpm. Detection efficiency (1 microcurie I131 a t 10 cm): 4400 cpm.
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NUCLEAR INSTRUMENT AND CHEMICAL CORPORATION 251 West Erie Street, Chicago 10, Illinois LEADERS IN MAKING RADIOACTIVITY COUNT For further information, circle number 30 A on Readers' Service Card, page 69 λ
30 A
The fourth edition of this highly re garded manual represents a considerable change in emphasis and length. The authors' preface sets forth their aims: emphasis of the research approach, stimulation of students' interest in organic chemistry as a whole, and en couragement of ingenuity and selfreliance in solving problems. These aims are served by new material in Chapter 8, "The Use of Spectroscopic Methods for Functional Group Deter mination" (detection?), which gives a brief discussion of infrared spectro photometry and a two-page chart show ing the characteristic group frequencies. There is a discussion of the advantages of ultraviolet methods and a good sec tion on the use of model compounds. The chapter is well supplied with refer ences, and is worth the space required. It should give students an intelligent understanding of the use of such spectra, something they might not get otherwise until much later. Chapter 12, "Introduction to the Solution of Structural Problems," is a somewhat expanded version of "The Interpretation of Experimental Data" in the second edition. Again, the extra space is justified by the good common sense shown in the section on "Inter pretation of Molecular Formula" (pp. 353-354). For example, the statement appears (p. 354) that a molecular for mula for a compound containing only carbon, hydrogen, and oxygen must con tain an even number of hydrogen atoms. This reviewer, and about a dozen Ph.D. colleagues who were questioned, all agreed that it was a new idea to them and that bigosh! it is true if free radicals are barred. In future revisions, the reviewer sug gests that information be given about limitations imposed by real quantitative analytical data with uncertainties per missible in ACS publications. ANALYTICAL
CHEMISTRY
