Quantcast Figure 2-24. Spinning-top test. - Fundamentals of X-Ray Physics

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
Figure 2-24. Spinning-top test.
a. The "top" is a flat metal disk with a small hole drilled near one edge (figure
2-24A); it is placed above an x-ray film or cassette and made to spin while a short
exposure is made. In fully rectified current of 60 cycles, there are 120 pulsations a
second (with a half-wave rectifier there are 60): x-rays are produced by each of these
pulsations. The developed film will show a dot for each pulsation occurring during the
given exposure time. If all four rectifiers are operating properly, there will be one dot for
each 1/120 second of exposure used (60-cycle AC).
b. For example, for an exposure obtained in 1/10 second, 12 dark dots should
show on the film (figure 2-24B); if only 6 dots show (figure 2-24C) there were only 6
pulsations in 1/10 second, indicating that only half of the transformer output is reaching
the x-ray tube because one or more of the rectifiers requires replacement. The
spinning-top method may also be used to establish the accuracy of the timer.
One and two-pulse voltage patterns are produced by x-ray generators designed
to operate on single-phase AC. Generators that operate on three- phase AC produce
6-pulse and 12-pulse tube voltage patterns. Figure 2-25 shows some characteristics of
the four patterns as well as the alternating current form. Also shown is the voltage
ripple, which is the difference between the peak and minimum voltage. Two-pulse tube
voltage, for example, drops to zero value after each peak. Consequently, two-pulse
ripple is 100 percent. On the other hand, 6-pulse and 12-pulse voltages do not drop to
zero value. In 6-pulse systems, the voltage only drops a small amount before the next
pulse has reached the same amplitude, so 6-pulse ripple is 13.5 percent. For 12-pulse,
the voltage ripple is a mere 3.4 percent.

Medical News
Physical exercise helps women with breast cancer to better tolerate chemotherapy
Women with breast cancer who follow a physical exercise program...
Atrial fibrillation increases risk of only 1 type of heart attack
Refining the results of a 2013 study, researchers have found...
Nerve cells and blood vessels in eye 'talk' to prevent disease, study finds
A new study from scientists at The Scripps Research Institute...
University of Utah professor reframes conversation around domestic violence in new book
A few years ago, Sonia Salari was interviewed for an...
Team makes breakthrough in understanding Canavan disease
UC Davis investigators have settled a long-standing controversy surrounding the...
Most women don't know female-specific stroke signs
A national survey released today by The Ohio State University...
Study finds no health drawbacks to veterans' dual use of VA, Medicare Advantage
In a study that looked at a handful of quality...
Time to move Lyme Disease Awareness Month to April?
The month of May brings many things, among them Mother's...
Billions lack surgical care; report calls for change
In this country, we take it for granted that we...
AAP: Updated guidelines on newborn hospital release
(HealthDay)—The American Academy of Pediatrics (AAP) has just released updated...
Increased Mortality Tied to Fatty Liver Disease Spectrum (CME/CE)
(MedPage Today) -- Researchers also report increasing rates of heart...
Multiphoton microscopy reveals features of basal cell carcinoma
(HealthDay)—Noninvasive multiphoton microscopy (MPM) imaging can reveal characteristic features of...
CardioBreak: Embolic Protection, Sugar Substitutes, and 'Fatins'
(MedPage Today) -- Recent developments of interest in cardiovascular medicine....
Hemoglobin glycation index IDs harms, benefits of T2DM Tx
(HealthDay)—The effect of intensive versus standard type 2 diabetes treatment...
Study Pinpoints Potential Regulators of Brown Fat (CME/CE)
(MedPage Today) -- Deep proling uncovers adipose tissue-selective long-non-coding RNA...
Food industry tries to block Vermont's GMO labeling law
Food industry lawyers say there's not enough time to implement...
Doctors say head lice should not bar kids from school
(HealthDay)—Outbreaks of head lice in kids can be effectively treated...
An explanation of wild birds' role in avian flu outbreak
Wild birds are believed to be behind the first major...
Brain balances perception and action when caught in an illusion
Two wrongs can make a right, at least in the...
New app can detect sleep apnea events via smartphone
Determining whether your snoring is merely annoying, or crosses the...

Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +