BNMR/BNQR MUD file reader and asymmetry calculator
Project description
bdata
Beta-data package. The bdata object is largely a data container, designed to read out MUD data files and to provide user-friendly access BNMR/BNQR data.
Installation
- Install using pip:
pip install bdata
- Export environment variables for finding data files (add to
.bashrc
or similar)export BNMR_ARCHIVE=/path/bnmr/
export BNQR_ARCHIVE=/path/bnqr/
Object Map
Constructor:
bdata(run_number,year=0,filename='')
Examples:
bd = bdata(40001) # read run 40001 from the current year.
bd = bdata(40001,year=2017) # read run 40001 from year 2017.
bd = bdata(0,filename='filename.msr') # read file from local memory, run number unused
Functions:
Signature | Description |
---|---|
asym(option="",omit="",rebin=1,hist_select='') |
Calculate asymmetry. See below for docstring. |
beam_kev() |
Get beam implantation energy in keV |
get_pulse_s() |
Get beam pulse duration in s |
Misc Notes
The bdict objects allow for the calling of dictionary keys like an object attribute. For example, bd.ppg.beam_on or bd.ppg['beam_on'] have the exact same output. Note that reserved characters such as '+' cannot be used in this manner.
Set the location of the data archive via environment variables "BNMR_ARCHIVE" and "BNQR_ARCHIVE". This would be something like "/data1/bnmr/dlog/" on linbnmr2 or "~/triumf/data/bnmr/" on muesli or lincmms.
The various object containers returned have customized defined "magic" functions for common comparison and mathematical operators. So one can do bd.ppg.beam_on*5
and get 5 times the beam on time, stored in the mean property of that object.
Note that the object representation has been nicely formatted as well.
bdata.asym() docstring
usage: asym(option="",omit="",rebin=1,hist_select='')
Inputs:
options: see below for details
omit: 1f bins to omit if space seperated string in options
is not feasible. See options description below.
rebin: SLR only. Weighted average over 'rebin' bins to
reduce array length by a factor of rebin.
hist_select: string to specify which histograms get combined into
making the asymmetry calculation. Deliminate
with [,] or [;]. Histogram names cannot
therefore contain either of these characters.
Asymmetry calculation outline (with default detectors) ---------------
Split helicity (NMR): (F-B)/(F+B) for each
Combined helicity (NMR): (r-1)/(r+1)
where r = sqrt([(B+)(F-)]/[(F+)(B-)])
Split helicity (NQR): (R-L)/(R+L) for each
Combined helicity (NQR): (r-1)/(r+1)
where r = sqrt([(L+)(R-)]/[(R+)(L-)])
Alpha diffusion (NQR) sum(AL0)/sum(L+R)
Alpha tagged (NQR) same as NQR, but using the tagged counters
Histogram Selection ---------------------------------------------------
If we wished to do a simple asymmetry calculation in the form of
(F-B)/(F+B)
for each helicity, then
|--| |--| paired counter location
hist_select = 'F+,F-,B+,B-'
|-----| paired helicities
|-----|
for alpha diffusion calculations append the two alpha counters
hist_select = 'R+,R-,L+,L-,A+,A-
for alpha tagged calculations do the following
hist_select = 'R+,R-,L+,L-,TR+,TR-,TL+,TL-,nTR+,nTR-,nTL+,nTL-'
where TR is the right counter tagged (coincident) with alphas,
TL is the left counter tagged with alphas,
nTR is the right counter tagged with !alphas (absence of),
nLR is the right counter tagged with !alphas,
Status of Data Corrections --------------------------------------------
SLR/2H:
Removes prebeam bins.
Subtract mean of prebeam bins from raw counts
(does not treat error propagation from this. Errors are
still treated as Poisson, despite not being integers)
Rebinning:
returned time is average time over rebin range
returned asym is weighted mean
1F:
Allows manual removal of unwanted bins.
Scan Combination:
Multiscans are considered as a single scan with long
integration time. Histogram bins are summed according to
their frequency bin, errors are Poisson.
1N:
Same as 1F. Uses the neutral beam monitor values to calculate
asymetries in the same manner as the NMR calculation.
2E:
Prebeam bin removal.
Postbeam bin removal. Assumes beamoff time is 0.
Splits saved 1D histograms into 2D.
Asymmetry calculations:
raw: calculated through differences method (as described in
the asymmetry calculation outline)
dif: let 0 be the index of the centermost scan in time. dif
asymmetries are then calculated via raw[i+1]-raw[i-1],
where "raw" is as calculated in the above line, for each
of the three types: +,-,combined
sl: take a weighted least squares fit to the two bins prior
and the two bins after the center bin (in time). For
each find the value of the asymmetry at the center time
position. Take the difference: post-prior
Return value depends on option provided:
SLR DESCRIPTIONS --------------------------------------------------
"": dictionary of 2D numpy arrays keyed by
{"p","n","c","time_s"} for each helicity and combination
(val,err). Default return state for unrecognized options
"h": dictionary 2D numpy arrays keyed by {"p","n","time_s"} for
each helicity (val,err).
"p": 2D np array of up helicity state [time_s,val,err].
"n": 2D np array of down helicity state [time_s,val,err].
"c": 2D np array of combined asymmetry [time_s,val,err].
"ad": 2D np array of alpha diffusion ratio [time_s,val,err].
"at": dictionary of alpha tagged asymmetries key:[val,err].
Keys:
'time_s' : 1D array of times in seconds
'p_wiA','n_wiA','c_wiA': coincident with alpha
'p_noA','n_noA','c_noA': coincident with no alpha
'p_noT','n_noT','c_noT': untagged
where p,n,c refer to pos helicity, neg helicity, combined
helicity respectively. Only in 2h mode.
1F DESCRIPTIONS ---------------------------------------------------
all options can include a space deliminated list of bins or
ranges of bins which will be omitted. ex: "raw 1 2 5-20 3"
"": dictionary of 2D numpy arrays keyed by {p,n,c,freq} for each
helicity and combination [val,err]. Default return state
for unrecognized options.
"r": Dictionary of 2D numpy arrays keyed by {p,n} for each
helicity (val,err), but listed by bin, not combined by
frequency.
"h": get unshifted +/- helicity scan-combined asymmetries as a
dictionary {'p':(val,err),'n':(val,err),'freq'}
"p": get pos helicity states as tuple, combined by frequency
(freq,val,err)
"n": similar to p but for negative helicity states
"c": get combined helicity states as tuple (freq,val,err)
2E DESCRIPTIONS ---------------------------------------------------
Takes no options. Returns a dictionary with the keys:
'dif_p': [val,err][frequency] of pos. helicity asymmetry
'dif_n': [ve][f] of negative helicity asymmetry
'dif_c': [ve][f] of combined helicity asymmetry
'raw_p': [ve][f][time] raw asymmetries of each time bin. Pos hel.
'raw_n': [ve][f][t] negative helicity.
'raw_c': [ve][f][t] combined helicity
'freq': [f] frequency values
'time': [t] time bin values
'sl_p': [ve][f] pos. hel. of asymmetry calcuated through slopes
of pre and post middle time bin. Slope method only
for >= 5 time bins, corresponds to >= 3 RF on delays
'sl_n': [ve][f] negative helicity.
'sl_c': [ve][f] combined helicity.
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