Change request #749

Move instrument, ontime, livetime and deadc attributes to GObservation base class

Added by Knödlseder Jürgen almost 14 years ago. Updated almost 13 years ago.

Status:NewStart date:02/06/2013
Priority:NormalDue date:
Assigned To:-% Done:

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Description

All classes that are derived from GObservation implement the attributes
  • instrument name
  • ontime
  • livetime
  • deadtime correction factor

It is therefore reasonable to move these attributes in the base class and to add methods for setting and retrieving these attributes. They can then be removed from the instrument specific observation classes.

Recurrence

No recurrence.

History

#1 Updated by Deil Christoph almost 13 years ago

While doing this, would it be possible to clarify what deadc is (and maybe choose a more explicit name)?

Is it a time? Or a correction factor?

In HESS we call this the “deadtime correction factor”:
t_live = t_obs * (1 - deadtime_correction_factor)
and this the “deadtime”:
t_dead = deadtime_correction_factor * t_obs

In GCTAObservation I see deadc twice:

    virtual double              deadc(const GTime& time) const;
    void                deadc(const double& deadc);

So deadc is used as “deadtime correction factor” and “deadtime” in different places?

#2 Updated by Knödlseder Jürgen almost 13 years ago

Deil Christoph wrote:

While doing this, would it be possible to clarify what deadc is (and maybe choose a more explicit name)?

deadc is the OGIP name, and indeed, it’s the deadtime correction factor.

Is it a time? Or a correction factor?

In HESS we call this the “deadtime correction factor”:
t_live = t_obs * (1 - deadtime_correction_factor)
and this the “deadtime”:
t_dead = deadtime_correction_factor * t_obs

It’s exactly this.

In GCTAObservation I see deadc twice:
[...]

So deadc is used as “deadtime correction factor” and “deadtime” in different places?

The first method is to retrieve the value as function of time, the second is to set it as a constant. This is not very consistent, but only the first is imposed by the interface (i.e. in general, deadc may be time dependent) while the second is CTA specific, where deadc is a constant for a given observation (deadc is actually a keyword in Karl’s event list format).

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