def monitor_normalize(sansdata,mon0=1e8):
""""\
Given a SansData object, normalize the data to the provided monitor
**Inputs**
sansdata (sans2d): data in
mon0 (float): provided monitor
**Returns**
output (sans2d): corrected for dead time
2010-01-01 Andrew Jackson?
"""
monitor=sansdata.metadata['run.moncnt']
result=sansdata.data.x*mon0/monitor
res=SansData()
res.data.x=result
res.metadata=deepcopy(sansdata.metadata)
#added res.q
res.q=copy(sansdata.q)
res.qx=copy(sansdata.qx)
res.qy=copy(sansdata.qy)
res.theta=copy(sansdata.theta)
return res
def correct_dead_time(sansdata,deadtime=3.4e-6):
"""\
Correct for the detector recovery time after each detected event
(suppresses counts as count rate increases)
**Inputs**
sansdata (sans2d): data in
deadtime (float): detector dead time (nonparalyzing?)
**Returns**
output (sans2d): corrected for dead time
2010-01-01 Andrew Jackson?
"""
dscale = 1/(1-deadtime*(np.sum(sansdata.data.x)/sansdata.metadata["run.rtime"]))
result = SansData()
result.data.x = sansdata.data.x*dscale
result.metadata=deepcopy(sansdata.metadata)
result.q = copy(sansdata.q)
result.qx = copy(sansdata.qx)
result.qy = copy(sansdata.qy)
result.theta = copy(sansdata.theta)
return result
def PixelsToQ(data, correct_solid_angle=True):
"""
generate a q_map for sansdata. Each pixel will have 4 values: (qx,qy,q,theta)
**Inputs**
data (sans2d): data in
correct_solid_angle {Correct solid angle} (bool): Apply correction for mapping
curved Ewald sphere to flat detector
**Returns**
output (sans2d): converted to I vs. Qx, Qy
2016-04-06 Brian Maranville
"""
L2=data.metadata['det.dis']
x0=data.metadata['det.beamx'] #should be close to 64
y0=data.metadata['det.beamy'] #should be close to 64
wavelength=data.metadata['resolution.lmda']
shape=data.data.x.shape
qx=np.empty(shape,'Float64')
qy=np.empty(shape,'Float64')
x,y = np.indices(shape)
X=data.metadata['det.pixelsizex']/10.0*(x-x0) # in mm in nexus
Y=data.metadata['det.pixelsizey']/10.0*(y-y0)
r=np.sqrt(X**2+Y**2)
theta=np.arctan2(r,L2*100)/2 #remember to convert L2 to cm from meters
q=(4*np.pi/wavelength)*np.sin(theta)
alpha=np.arctan2(Y,X)
qx=q*np.cos(alpha)
qy=q*np.sin(alpha)
if correct_solid_angle:
data.data.x = data.data.x * (np.cos(theta)**3)
res=SansData()
res.data=copy(data.data)
res.metadata=deepcopy(data.metadata)
#Adding res.q
res.q = q
res.qx=qx
res.qy=qy
res.theta=theta
return res
def correct_detector_efficiency(sansdata):
"""
Given a SansData object, corrects for the efficiency of the detection process
**Inputs**
sansdata (sans2d): data in
**Returns**
output (sans2d): corrected for efficiency
2016-08-03 Brian Maranville and Andrew Jackson
"""
L2=sansdata.metadata['det.dis']
lambd = sansdata.metadata["resolution.lmda"]
shape=sansdata.data.x.shape
(x0,y0) = np.shape(sansdata.data.x)
x,y = np.indices(shape)
X = sansdata.metadata['det.pixelsizex']/10.0*(x-x0/2)
Y = sansdata.metadata['det.pixelsizey']/10.0*(y-y0/2)
r=np.sqrt(X**2+Y**2)
theta_det=np.arctan2(r,L2*100)/2
stAl = 0.00967*lambd*0.8 #dimensionless, constants from JGB memo
stHe = 0.146*lambd*2.5
ff = np.exp(-stAl/np.cos(theta_det))*(1-np.exp(-stHe/np.cos(theta_det))) / ( np.exp(-stAl)*(1-np.exp(-stHe)) )
res=SansData()
res.data.x=sansdata.data.x/ff
#if not sansdata.data.variance==None:
#res.data.variance=sansdata.data.variance/ff
res.metadata=deepcopy(sansdata.metadata)
res.q = copy(sansdata.q)
res.qx=copy(sansdata.qx)
res.qy=copy(sansdata.qy)
#note that the theta calculated for this correction is based on the center of the
#detector and NOT the center of the beam. Thus leave the q-relevant theta alone.
res.theta=copy(sansdata.theta)
return res
