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  <HEAD><TITLE>CHICAGO Neutron Monitor Data Base</TITLE></HEAD>
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<h2 align=center>Data Base of CHICAGO  Neutron Monitor</h2>

CHICAGO  Neutron Monitor was situated in CHICAGO, USA<BR>

It was a project of The ENRICO FERMI INST. FOR NUCLEAR STUDIES<BR><BR>

Latitude: 41.83N<BR>    Longitude: -87.67W<BR> 
Altitude: 200 m<BR>     Rigidity (1965): 1.72 GV<BR>
Standard atmoshperic pressure:  1000 mb<BR>
Barometric coefficient (1987):  -0.72 %/mb<BR>
SF=100 (The mean count is around 257500/hour or 4300/min,)<BR><BR>



Database contents of Alert  neutron monitor data worked from 1957 to 1971 (12 IGY). 
The interval of accumulation: hourly from 1957; besides, 1-minute data from 1957. 
An interactive access is possible to this database and FTP
as well. <h3>Interactive access</h3> Data in this regime are
available in graphical and in digital presentation as well. All
graphical plots are given relative to February 1987.
<h3>Access by FTP</h3>
One-minute data are in directory ftp_NM1, hourly data in
directory ftp_NM. Ground Level Enhancement (GLE) data are in the
GLE directory. One-type data are presented in their own Format:
hourly data in format C, 1-minute data in W format, and GLE data
in GLE format.
<p> There are three types of 1-minute data: neutron
monitor data corrected for atmospheric pressure (C), atmospheric
pressure (P), and neutron monitor data uncorrected for atmospheric
pressure (U).

Hourly data are presented uncorrected
(U) and corrected for atmospheric pressure (P).
Pressure corrected hourly data are kept as original (O)
and corrected (C).
<!-- Corrected data firstly are the same as original data, but they may be
corrected in future e.g. for the snow effect, for the possible
long time jumps, when the sweing is required, slow drift, and, at
last, cleaning data for the occasional mistakes.
The special
programs are closed in the corresponding folders to look through
data in the grafical regime. They should be replaced on your
computer to be used. Thus, to look through 1-minute and hourly
data the program Plot_DAT should be used, and for GLE data use
Plot_GLE program. After the corresponding Folder is  opened by
command OPEN, the following sort should be done: all type ( *.w1u,
*.w1p, *.w1c) - select and plot 1-minute data, all type (*.?0u,
*.?0p, *.?0o, *.?0c) - select and plot hourly data. --> </BODY>
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