D. Rubin, S.Isaacman, A.Long
<br>June 9, 2005. (updated June 9, 2005)
<p>
<h1>Lattice with no wigglers</h1>
<p>
<h3>Introduction</h3>
The lattice bmad_nowig_250505.lat has energy 1.89GeV and no wigglers. The summary
of the properties of the <a href="../cesrc/bmad_nowig_250505.html"> no wiggler lattice </a>
indicate a damping time of 1/2 second, energy spread 0.22% and emittance of 20nm. With a
synchrotron tune of 0.049 the bunch length is 6.2mm. Tunes, solenoid compensation, pretzel, etc.
are similar to standard cesr-c 12 wiggler optics (hibetainj_20040628_v01.lat).  
<p>

<h3> Simulation </h3>
We track 500 particles for 1e6 turns. (The damping time is 200k turns.)
Computed <a href="lum_v_turn_310505.gif"> luminosity vs turn </a> indicates convergence
in less than 1 million turns.
The simulated <a href="../cesrc/bb_310505_030805.gif"> luminosity </a> and
<a href="../cesrc/bbts_310505_030805.gif"> tuneshift </a> for 
the no wiggler lattice, with sigma_l=6.2mm, Qz=0.049 are compared
with standard cesr-c (hibetainj_20040628_v01) and cesr-c with Qz=0.089 and sigma_l=13.2 mm.
The horizontal and vertical tunes are (Qx=0.532,Qy=0.594).  
<p>
In the wiggler off optics, luminosity is increasing roughly quadratically with current to 1.4mA.
But
the luminosity lifetime is limited to about 1.2mA. At 1.4mA/bunch the loss of 9 of 500 particles
in 1e6 turns corresponds to a lifetime of about 2minutes.  
The current limit might be increased by increasing horizontal emittance. The horizontal emittance
in the wiggler off lattice is about 1/6 of horizontal emittance in the 12 wiggler lattice. 
<p>
The higher tune shift as compared to the 12 wiggler optics is presumably due to the
shorter bunch and/or lower synchrotron tune.