TP nominal interaction rate etc.
From:
Date: 12/17/97
Time: 10:09:29 AM
Remote Name: 137.138.115.189
Comments
Dear Colleagues,
As I announced sometime ago, we agree to use L(nominal) = 2 * 10^32 cm^-2
s^-1 sigma(inelastic) = 80 mb which leads to a interaction rate of
N(interaction) = 16 MHz. Georg von Holtey calculated for me that only 74.4% of
40MHz bunch crossing frequency have indeed bunches colliding with other bunches,
i.e. bunches collide with 30MHz frequency (not equally spaced) at IP8 where the
crossing point is shifted by 3/2 bunch spacing from the nominal point. This
reduction is due to the bunch structure with missing bunches. Thus 16*10^6 pp
interactions are spread over 30*10^6 bunch crossings. This leads to a bunch
crossing frequency with one or more pp interactions of f(any interaction) = 14
MHz and a bunch crossing frequency with only one pp interaction of f(one
interaction) = 9.39 MHz. and 67% of b anti-b pairs are produced in the event
with one pp interaction, i.e. b anti-b production rate is L(nominal)*sigma(b
anti-b) = 10^5 / sec [ sigma(b anti-b) = 500 microb] of which 10^5*0.67 =
6.7*10^4 / sec b anti-b pairs are "useful". I hope that I did not make any
mistake.... If so, these are nominal rates to be used in the Technical Proposal.
yours Tatsuya
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