contrast.scans package

Module contents

Provides basic acquisition macros and base classes for custom macros.

Submodules

contrast.scans.AScan module

class contrast.scans.AScan.AScan(*args, **kwargs)

Bases: contrast.scans.Scan.SoftwareScan

This class generates the macro `ascan`

Software scan one or more motors in parallel.

ascan <motor1> <start> <stop> ... <intervals> <exp_time>

class contrast.scans.AScan.DScan(*args, **kwargs)

Bases: contrast.scans.AScan.AScan

This class generates the macro `dscan`

Software scan one or more motors in parallel, with positions relative to each motor’s current one. Moves back afterwards.

dscan <motor1> <start> <stop> <intervals> ... <exp_time>

contrast.scans.Mesh module

class contrast.scans.Mesh.Mesh(*args, **kwargs)

Bases: contrast.scans.Scan.SoftwareScan

This class generates the macro `mesh`

Software scan on a regular grid of N motors.

mesh <motor1> <start> <stop> <intervals> ... <exp_time>

optional keyword arguments:

jitter: float … Randomizes perfect grid positions.

class contrast.scans.Mesh.DMesh(*args, **kwargs)

Bases: contrast.scans.Mesh.Mesh

This class generates the macro `dmesh`

Software scan on a regular grid of N motors, with positions relative to each motor’s current one. Moves motors back at the end.

dmesh <motor1> <start> <stop> <intervals> ... <exp_time>

class contrast.scans.Mesh.MeshJMesh(m1, l1_l, l1_u, n1, j1, sl1_l, sl1_u, sn1, sj1, m2, l2_l, l2_u, n2, j2, sl2_l, sl2_u, sn2, sj2, exptime, **kwargs)

Bases: contrast.scans.Scan.SoftwareScan

This class generates the macro `meshjmesh`

2D Software scan for NearField ptychography. Each point of a larger 2D mesh scan is another smaller 2D mesh.

meshjmesh <motor1> <abs_start1> <abs_stop1> <nr_int1> <jit_amp1>

<rel_start_sub1> <rel_stop_sub1> <nr_int_sub1> <jit_amp_sub1>

<motor1> <abs_start2> <abs_stop2> <nr_int2> <jit_amp2>

<rel_start_sub2> <rel_stop_sub2> <nr_int_sub2> <jit_amp_sub2>

<exposure_time>

The start and stop position of the coarse mesh are in aboslute coordinates, while the start and stop positions of the submesh are relative coordiantes.

2nd axis is the fast axis.

contrast.scans.Scan module

class contrast.scans.Scan.SoftwareScan(exposuretime)

Bases: object

Base class for the normal sardana-style software-controlled scan. Respects the availability and deadlines managed by env.scheduler, honours env.shapshot, and acts on all active detectors, trigger sources, and recorders.

The constructor should parse the parameters of the derived macro.

Parameters:exposuretime (float) – Exposure time to pass on to detectors etc.

_calc_time_needed()

Estimates the time needed for performing the next acquisition. This can be done based on the input parameters, or on the timing of previous points.

_before_scan()

Placeholder method for users to hook actions onto scan classes after import. For example opening a shutter:

def pre_scan_stuff(slf):
    print("Maybe open a shutter here?")
SoftwareScan._before_scan = pre_scan_stuff

_after_scan()

Placeholder method for users to hook actions onto scan classes after import, see _before_scan.

_before_move()

Gets called for each step, and can be used for example to check that the instrument is ready for the next acquisition, that there is beam in the machine, etc.

_before_arm()

Gets called for each step. See _before_move.

_while_acquiring()

Gets called repeatedly while the detectors detect. Useful for printing a progress bar, for example.

_before_start()

Gets called for each step. See _before_move.

run()

This is the main acquisition loop where interaction with motors, detectors and other Gadget objects happens.

_generate_positions()

Override this method. Function or generator which returns or yields an iterable of dicts,

{motorA.name: posA, motorB.name: posB, ...}

class contrast.scans.Scan.LoopScan(intervals, exposuretime=1.0)

Bases: contrast.scans.Scan.SoftwareScan

This class generates the macro `loopscan`

A software scan with no motor movements. Number of exposures is <intervals> + 1, for consistency with ascan, dscan etc.

loopscan <intervals> <exp_time>

class contrast.scans.Scan.Ct(exp_time=1, print_nd=True)

Bases: object

This class generates the macro `ct`

Make a single acquisition on the active detectors without recording data. Optional argument <exp_time> specifies exposure time, the default is 1.0.

ct [<exp_time>]

_before_ct()

Placeholder method for users to hook actions onto scan classes after import.

_after_ct()

Placeholder method for users to hook actions onto scan classes after import.

contrast.scans.Spiral module

class contrast.scans.Spiral.SpiralScan(m1, m2, stepsize, npos, exptime, **kwargs)

Bases: contrast.scans.AScan.DScan

This class generates the macro `spiralscan`

Software scan across a 2D Archimedes spiral centered on the current position.

spiralscan <motor1> <motor2> <stepsize> <positions> <exp_time>

class contrast.scans.Spiral.FermatScan(m1, l1_l, l1_u, m2, l2_l, l2_u, stepsize, exptime, **kwargs)

Bases: contrast.scans.AScan.AScan

This class generates the macro `fermatscan`

Software scan in the shape of a fermat spiral (good for ptychography scan). The center of the spiral will be the center of the given rectangle. Both motors have to be in the same units.

fermatscan <motor1> <start> <stop> <motor2> <start> <stop> <stepsize> <exp_time>

optional keyword arguments:

optimize: boolean … will try to solve the traveling salesman problem

WARNING: can be slow for large scans!

contrast.scans.Tweak module

contrast.scans.Tweak.getarrowkey()

A function which waits for a keypress and returns one of the above constants.

class contrast.scans.Tweak.Tweak(*args, **kwargs)

Bases: contrast.scans.Mesh.Mesh

This class generates the macro `tweak`

An interactive scan where motor positions are chosen manually for each point. Useful for tweaking motors and reading the currently active detectors after each step.

tweak <motor1> <stepsize1> [<motor2> <stepsize2>] <exp_time>