Description of Daily Flux Data for the COSPIN High Energy Telescope (HET) 

   This file contains daily average fluxes (cm^2 s sr MeV/n)^-1 of 
protons and helium nuclei stopping in the detectors K1-K6 of the Ulysses 
COSPIN High Energy Telescope (HET).  The HET is described in detail by 
Simpson et al. (Astron. & Astrophys., vol 92, pp. 365-399, 1992).  
   The particles contributing to these fluxes have been identified by 
pulse height analysis.  Therefore even in quiet times, when backgrounds 
dominate the counting rates, it is possible to separate the very low 
fluxes of protons and helium from the backgrounds in the telescope.  
   The energy intervals are as shown in the titles and correspond to 
particles which trigger exactly the same detectors in the telescope that 
are required to produce counts in the counting rates H4 (no penetration 
beyond K3) and H5 (no penetration beyond K6).  By comparison of A) the 
total PHA events with detector triggers identical to those required for 
the H4 and H5 counting rates to B) the measured H4 and H5 counting rates, 
fluxes can be derived even though the PHA information is returned for 
only a small fraction of the incident events.  
   The errors shown, also in units of (cm^2 s sr MeV/n)^-1, correspond 
to one-sigma counting errors, assuming Poisson statistics.  Additional 
systematic uncertainties due to such effects as the variation of 
effective geometric factor with energy, or the variation in the minimum 
and maximum energies contributing to the counting rates as a function of 
angle of incidence, are difficult to estimate precisely but are probably 
of the order of 10-20 percent. 
   Missing or invalid data are represented by values of -1, as are 
meaningless fields such as the error on a measured flux of zero (no 
events registered during the accumulation interval).  In some cases, 
particularly during solar particle events when the overwhelming majority 
of incident particles are low energy protons, competition for telemetry 
may lead to no events being registered in the higher energy proton or 
helium energy bins even though their true fluxes may be significantly 
elevated above quiet time levels.  
   The times, given as fractional year after 1900.0 and as fractional 
day of year (noon Jan. 1 = 1.5) correspond to the midpoints of the 
accumulation intervals. 

--------------------------- 

As an example of the data, the title lines and first two lines of data 
from the UDS site are: 

--------------------------- 
Column   Contents                                                        
   1      Fractional year - 1900                                          
   2      day of year                                                     
   3      H4 proton flux (39-70 MeV)                                      
   4      Error for H4 protons                                            
   5      H5 proton flux (71-94 MeV)                                      
   6      Error for H5 protons                                            
   7      H4 helium flux (39-71 MeV/n)                                    
   8      Error for H4 helium                                             
   9      H5 helium flux (72-95 MeV/n)                                    
  10      Error on H5 helium                                              
90.80959000  296.5  3.338E-03  8.679E-05  1.185E-03  7.821E-05 3.058E-05  9.235E-06  0.000E+00 -1.000E+00 
90.81233000  297.5  1.795E-03  2.692E-05  4.464E-04  2.009E-05 7.702E-06  1.926E-06  1.037E-06  1.037E-06 

------------------------------------------------------ 
     R. Bruce McKibben, Sr. Scientist 
     Enrico Fermi Institute, University of Chicago 
     933 E. 56th St., Chicago, IL 60637 
     Phone:  773-702-7851       FAX:  773-702-6645 
     e-mail:  mckibben@odysseus.uchicago.edu 
------------------------------------------------------