Tutorial: ELS counts

Problem 1

I want to get VEX/ELS count data between 2007-10-05T01:30:00 to 2007-10-05T01:50:00.

Answer 1

A recommended way is to use a data center as

>>> import datetime
>>> t0 = datetime.datetime(2007, 10, 5, 1, 30)
>>> t1 = datetime.datetime(2007, 10, 5, 1, 50)

>>> import irfpy.vels.rawdata
>>> dc = irfpy.vels.rawdata.DataCenterEls()
>>> tlist, elsmatrix = dc.get_array(t0, t1)

Here tlist includes the list of the (start) time, and elsmatrix contains a list of numpy array.

>>> print(tlist)
[datetime.datetime(2007, 10, 5, 1, 30, 3, 690002)
 datetime.datetime(2007, 10, 5, 1, 30, 7, 690000)
 datetime.datetime(2007, 10, 5, 1, 30, 16, 129001)
...
 datetime.datetime(2007, 10, 5, 1, 49, 53, 538999)
 datetime.datetime(2007, 10, 5, 1, 49, 57, 538998)]

>>> print(len(tlist))
261

>>> print(len(elsmatrix))
261

>>> elsmatrix = np.array(elsmatrix)   # One can convert to the numpy array
>>> print(elsmatrix.shape)    # The array has a shape of (ndata=261, energy=128, dir=16)
(261, 128, 16)

Answer 1 (alternative, no more supported way)

The function irfpy.vels.scidata.get_counts() will provide the ELS data.

>>> import irfpy.vels.scidata as velsdata
>>> import datetime
>>> t0 = datetime.datetime(2007, 10, 5, 1, 30)
>>> t1 = datetime.datetime(2007, 10, 5, 1, 50)
>>> tlist, elsmatrix = velsdata.get_counts(t0, t1)

The returned is a tuple, with the list of the start time and the matrix.

>>> print(tlist)
[datetime.datetime(2007, 10, 5, 1, 30, 3, 690002)
 datetime.datetime(2007, 10, 5, 1, 30, 7, 690000)
 datetime.datetime(2007, 10, 5, 1, 30, 16, 129001)
 datetime.datetime(2007, 10, 5, 1, 30, 20, 128999)
...
 datetime.datetime(2007, 10, 5, 1, 49, 49, 539001)
 datetime.datetime(2007, 10, 5, 1, 49, 53, 538999)
 datetime.datetime(2007, 10, 5, 1, 49, 57, 538998)]

>>> print(len(tlist))
261

>>> print(elsmatrix)
[[[  0.   0.   0. ...,   0.   0.   0.]
  [  0.   0.   0. ...,   0.   0.   0.]
  [  0.   0.   0. ...,   0.   0.   0.]
  ...,
  [  0.   0.   0. ...,   0.   0.   0.]
  [  0.   0.   0. ...,   0.   0.   0.]
  [  0.   0.   0. ...,   0.   0.   0.]]
...
 [[  0.   0.   0. ...,   0.   0.   0.]
  [  0.   0.   0. ...,   0.   0.   0.]
  [  1.   0.   0. ...,   2.   1.   0.]
  ...,
  [  0.   1.   0. ...,  21.  20.  16.]
  [  0.   0.   0. ...,  17.  15.  16.]
  [  0.   0.   0. ...,   2.   2.   5.]]]


>>> print(elsmatrix.shape)
(128, 16, 261)

During the given 20 minutes, ELS produced 261 spectra (here one spectrum is corresponding to a matrix with (E=128, S=16) shape). Each matrix has (E=128, S=16) shape, so that the full matrix has a shape of (128, 16, 261). The time observed can be referred to by tlist.

Warning

Note the order of the matrix is different from the recommended way.

Problem 2

I want to get MEX/ELS count data between 2007-10-20T07:30:00 to 2007-10-20T07:45:00.

Answer 2 (alternative, non-supported way)

Almost identical call to VEX/ELS, but one can use irfpy.mels.scidata.get_counts().

>>> import irfpy.mels.scidata as melsdata
>>> import datetime
>>> t0 = datetime.datetime(2007, 10, 20, 7, 30)
>>> t1 = datetime.datetime(2007, 10, 20, 7, 45)
>>> tlist, elsmatrix = melsdata.get_counts(t0, t1)

Check by yourself that the tilst has 197 elements, and elsmatrix is an array with a shape of (128, 16, 197).

Exercise

  1. What is the maximum count rate recorded by MEX/ELS for the time period between 2007-10-08T11:00:00 and 2007-10-08T14:00:00?

  2. How many energy and sector bins are recorded by zero counts for the time period between 2007-10-25T00:00:00 and 2007-10-25T01:00:00?