Intro:
WHENEVER LIFE GETS YOU DOWN, MRS. BROWN, AND THINGS SEEM HARD OR
TOUGH, AND PEOPLE ARE STUPID, OBNOXIOUS OR DAFT AND YOU FEEL THAT
YOU'VE HAD QUITE ENOUGH...
Just remember that you're standing on a planet that's evolving.
And revolving at 900 miles an hour,
That's orbiting at 19 miles a second, so it's reckoned,
A sun that is the source of all our power.
The sun and you and me and all the stars that we can see,
Are moving at a million miles a day
In an outer spiral arm, at 40,000 miles an hour,
Of the Galaxy we call the Milky Way.
Our Galaxy itself contains 100 billion stars
It's 100,000 light years side to side,
It bulges in the middle, 16,000 light years thick
But out by us it's just 3,000 light years wide
We're 30,000 light years from the galactic central point,
We go round every 200 million years
And our galaxy is only one of millions of billions
In this amazing and expanding Universe.
The Universe itself keeps on expanding and expanding
In all of the directions it can whizz
As fast as it can go, at the speed of light you know,
12 million miles a minute, and that's the fastest speed there is.
So remember when you're feeling very small and insecure
How amazingly unlikely is your birth
And pray that there's intelligent life somewhere up in space
Because there's bugger all down here on Earth.
Composer: Eric Idle/John de Prez
Author: Eric Idle
Performed by: Monty Python's Flying Circus
in Fermilab E791
(.pdf - "diamonds" are arrows to the right! Gotta love pdf!)
High Energy Physics Group, Department of Physics, Kansas State University, Manhattan, Kansas 66506
The above product of the ratios of the branching fractions in Fermilab E791 is measured. A gaussian curve is fit to the invariant mass plots of K+ K- p ± to identify the Ds ±. Invariant mass plots of K+ K- are fit with a Breit-Wigner curve to identify the j and the WA76 parameterization of f0(980) is used to identify the f0(980). In order to determine the detector efficiency for the decay f0(980) -> K+ K-, the Monte Carlo mass generation routine, ULMASS.F of Jetset 7.4, is modified to include the WA76 parameterization to generate the appropriate line-shape for the decay f0(980).
Authors: R. Debbe, S. Gushue, B. Moskowitz, J. Norris, J. Olness, F. Videbaek
Brookhaven National Lab, Upton NY 11973
Nuclear Instruments and Methods in Physics Research A 362 (1995) 253-260: text (.ps), figures (.pdf).
A ring-imaging Cherenkov counter read out by a 100-channel PMT of active area 10cmx10cm was operated successfully in a test beam at the BNL AGS with several radiator gases, including the heavy fluorocarbon C4 F10. Ring radii were measured for electrons, muons, pions and kaons over the particle momentum range from 2 to 12 GeV/c, and a best resolution of sigma_r/r=2.3% was obtained.
Authors: I Ben-Itzhak, K. D. Carnes, D. T. Johnson, P. J. Norris, O. L. Weaver
James R Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506
Physical Review A, Vol 49, Num 2, February 1994, pg 881-888 (.pdf)
The velocity dependence of methane ionization and fragmentation have
been studied using a coincidence time-of-flight technique. The
relative yields of single-ion, ion-pair, and ion-triple channels have
been determined for 1 - to 12-MeV proton impact. The
multiple-ionization cross sections have been determined and are in
accord with our model semiclassical Coulomb approximation
calculations. The single-ion channels resulting from the breakup of
CH4+*
were found to be independent of the collision velocity. Good
agreement with previous proton-impact measurements and with
electron-impact measurements is observed. On the other hand, the
ion-pair breakup channels of CH4++* show
surprising dependence on the collision velocity. The ion-pair data
are in reasonable agreement with fast-electron-impact measurements at
10 keV while differing significantly with a lower, 1-KeV,
electron-impact measurement.
Authors: I. Ben-Itzhak, K. D. Carnes, S. G. Ginther, D. T. Johnson, P. J. Norris, and O. L. Weaver
James R Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506
Nuclear Instruments and Methods in Physics Research B79(1993) 138-141.
Molecular fragmentation of diatomic and small polyatomic molecules by fast ion impact has been studied. The evaluation of the cross sections of the different fragmentation channels depends strongly on the recoil ion detection efficiency, er (single ions proportional to er, and ion pairs to er2, etc.). A method is suggested for the direct determination of this detection efficiency. This method is based on the fact that fast H2 + CH4 collisions produce C2+ fragments only in coincidence with H+ and H+2 fragments in which the H+m of the H+2 + C2+ ion pair was not detected and thus is proportional to 1 - er. Methane fragmentation caused by 1 MeV proton impact is used to evaluate directly the recoil ion detection effeciency and to demonstrate the method of deriving the cross sections of all breakup channels.
Authors: I. Ben-Itzhak, K. D. Carnes, S. G. Ginther, D. T. Johnson, P. J. Norris, and O. L. Weaver
James R Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506
Physical Review A, Vol 47, Num 5, May 1993, pg 3784-3757 (.pdf)
The cross sections of the different breakup channels of CH4, produced by 4-MeV proton impact, have been
measured using the coincidence time-of-flight technique. The relative
abundances of the different breakup channels were evaluated for
collisions in which the molecule broke into two charged fragments as
well as for collisions where only a single charged molecular ion or
fragment was produced. These relative abundances are compared to the
ones measured for photodissociation, and for electron and proton
impact. Only the
CH4+
ion survives long enough to be detected as a molecular ion, while
the doubly charged
CH42+
ion dissociates rapidly. The most probable final product of the
fragmentation of doubly charged methane as formed by fast-proton
impact is
H+
+
CH2++H.
The abundance of
Hm+
+
CHn+
(m+n <= 4) ion pairs decreases rapidly with increasing
m, as suggested by
Siegbahn [Chem. Phys. 66, 443(1982)].
The momentum of neutral fragments, in channels where they are
produced, is small in comparison with the momentum of the charged
fragments so that two-body breakup holds approximately. The deviation
from two-body breakup increases with increasing number of neutral
hydrogen atoms produced. The sensitivity of the experimental method
enabled us to extend the study of the fragmentation pattern of
CH42+
to include small breakup channels such as
CH42+
-->
H3+
+
CH+.
Furthermore, some breakup channels of the triply charged
CH43+
have been detected as triple coincidences.
