Recent Progress on Improving the RXTE Proportional Counter Array Instrumental Background

Dave Smith & Keith Jahoda (GSFC)
Rossi 2000 Meeting

22 March 2000

What's New? And What's Next?

• Background models are available for all gain epochs and source brightnesses

• Characteristics of the PCA residual background and the next generation models

Latest background models are available from

http://heasarc.gsfc.nasa.gov/docs/xte/pca_news.html

Details of these models, and their performance can be found by visiting

http://asd.gsfc.nasa.gov/~dasmith/pca_bkgd.html

Systematic Error in 3pcu (1 mCrab cts/s/3pcu; 2-10 keV)

Energy band	cts/s	cts/s/chan	% bkgd rate
2-10 keV	0.15	7.5E-3	1.5%
10-20 keV	0.03	1.3E-3	0.5%
20-50 keV	0.10	2.2E-3	0.6%

The residual background can be described as follows

• Daily variation in the 30-70 keV background

• Long term trend in the background subtracted light curve

Next generation models

• Model component based on either VLE rate or COR

• Subtract the long term trend from the data