HEXTE ---It takes a licking and keeps on ... ROCKING!
Space is a tough place. Repeated passages through the SAA, micro-meteorite attacks and general wear and tear take their toll on delicate spaceborne instrumentation. As the six year anniversary of the launch of RXTE past on December 30, 2001, we shine the spotlight on HEXTE---the High Energy X-ray Timing Experiment, built by a collaboration between University of California, San Diego (UCSD) and NASA.
HEXTE is composed of two clusters of 4 NaI/CsI phoswich scintillation detectors, each with an effective area of 800 square cm, covering the energy range 15 to 250 keV with an energy resolution of 9 keV at 60 keV.
Even observers with sources too faint for a significant detection nonetheless rely on HEXTE. This is because the faint background models get their information about the recent particle doses during SAA passages from the HEXTE particle monitor.
HEXTE Instrument Status
All HEXTE systems, including the photo-multiplier tubes, the phoswich detectors, the automatic gain control system and the electronic systems, continue to perform well.
As we on the RXTE teams are fond of saying, "HEXTE rocks!" Typically, each HEXTE cluster alternatively rocks on and off source each 32 seconds, and background is measured from the off-source pointings. But would you believe that the modulators have now made 6 million rocking motions each? HEXTE *really* rocks!
The microprocessors have not been rebooted in over 2 years!
The instrument response remains stable, with only small trends with time appearing. Tools are being developed now to remove this small effect.
To date, about 40 papers based on HEXTE results have appeared in the open literature (refereed and non-refereed). These results cover a broad range of source type and behavior, from the Coma Cluster and active galaxies, to galactic black hole transients and accreting pulsars.
HEXTE Highlight Science Topics
Here are a few of the most recent, and intriguing, science results that rely on HEXTE for the main analysis:
Put HEXTE into your next RXTE paper!
Curious about high energy cut-offs, or cyclotron resonance features? Take a look at the HEXTE data for your objects of interest. Now, with the release of our new RXTE Standard Data Products, archival research using HEXTE is easier than ever! Just look at the .gif files in the stdprod/GIFS directory for observations from AOs 0-3. You'll be able to tell at a glance whether a significant HEXTE signal is detected, and get an idea of its spectrum and light curve. (Standard Products will be the subject of an upcoming Highlights article in early 2002.)
If you have a question about RXTE, please send email to one of our help desks.