HRI Temporal Calibration Status

The gain (mean PHA channel) and quantum efficiency (count rate) of the ROSAT HRI are monitored frequently using N132D and the UV calibration lamp. The links below are to postscript files describing these quantities over the lifetime of the mission.

Note: The HV was mistakenly set back to 12 starting March 3, 1997 and was reset back to 13 on May 6, 1997, at 12:40 UT.

N132D

The on-axis calibration measurements of N132D are taken monthy which currently run through March 1998.

• Gain Variation
• Quantum Efficiency Variation
• PHA distribution
1997 April with HV level set to 12 (compare with Figure 19 in the HRI Calibration Report)

UV calibration Lamp

A small circular region near the detector's center is used for data taken up through April 1998.

• Gain Variation