reboost.hpge package

Submodules

reboost.hpge.psd module

reboost.hpge.psd._current_pulse_model(times, Amax, mu, sigma, tail_fraction, tau)

Analytic model for the current pulse in a Germanium detector.

Consists of a Gaussian and an exponential tail:

\[A(t) = A_{max}\times (1-p)\times \text{Gauss}(t,\mu,\sigma)+ A \times p (1-\text{Erf}((t-\mu)/sigma))\times \frac{e^{(t/\tau)}}{2e^{\mu/\tau}}\]
Parameters:

  • times (ArrayLike) – Array of times to compute current for

  • Amax (float) – Maximum current

  • mu (float) – Time of the maximum current.

  • sigma (float) – Width of the current pulse

  • tail_fraction (float) – Fraction of the tail in the pulse.

  • tau (float) – Time constant of the low time tail.

Returns:

The predicted current waveform for this energy deposit.

Return type:

NDArray

reboost.hpge.psd._drift_time_heuristic_impl(dt, edep)

Low-level implementation of the HPGe drift-time-based pulse-shape heuristic.

Accepts Awkward arrays and uses Numba to speed up the computation.

For each hit (collection of steps), the drift times and corresponding energies are sorted in ascending order. The function finds the optimal split point \(m\) that maximizes the identification metric:

\[I = \frac{|T_1 - T_2|}{E_\text{s}(E_1, E_2)}\]

where:

\[T_1 = \frac{\sum_{i < m} t_i E_i}{\sum_{i < m} E_i} \quad \text{and} \quad T_2 = \frac{\sum_{i \geq m} t_i E_i}{\sum_{i \geq m} E_i}\]

are the energy-weighted mean drift times of the two groups.

\[E_\text{scale}(E_1, E_2) = \frac{1}{\sqrt{E_1 E_2}}\]

is the scaling factor.

The function iterates over all possible values of \(m\) and selects the maximum I as the drift time heuristic value.

Parameters:

  • dt (ak.Array)

  • edep (ak.Array)

Return type:

NDArray

reboost.hpge.psd._estimate_current_impl(edep, dt, sigma, tail_fraction, tau, mean_AoE=0)

Estimate the maximum current that would be measured in the HPGe detector.

This is based on extracting a waveform with get_current_waveform() and finding the maxima of it.

Parameters:

  • edep (ak.Array) – Array of energies for each step.

  • drift_time – Array of drift times for each step.

  • sigma (float) – Sigma parameter of the current pulse model.

  • tail_fraction (float) – Tail-fraction parameter of the current pulse.

  • tau (float) – Tail parameter of the current pulse

  • mean_AoE (float) – The mean AoE value for this detector (to normalise current pulses).

  • dt (ak.Array)

Return type:

tuple[NDArray, NDArray]

reboost.hpge.psd._vectorized_erf(x)

Error function that can take in a numpy array.

Parameters:

x (ArrayLike)

Return type:

NDArray

reboost.hpge.psd.convolve_surface_response(surf_current, bulk_pulse)

Convolve the surface response pulse with the bulk current pulse.

This combines the current induced on the edge of the FCCD region with the bulk response on the p+ contact.

Parameters:

  • surf_current (ndarray) – array of the current induced via diffusion against time.

  • bulk_pulse (ndarray) – the pulse template to convolve the surface current with.

Returns:

the current waveform after convolution.

Return type:

ndarray[tuple[int, …], dtype[_ScalarType_co]]

reboost.hpge.psd.drift_time(xloc, yloc, zloc, dt_map, coord_offset=<Quantity([0 0 0], 'meter')>)

Calculates drift times for each step (cluster) in an HPGe detector.

Parameters:
Return type:

VectorOfVectors

reboost.hpge.psd.drift_time_heuristic(drift_time, edep)

HPGe drift-time-based pulse-shape heuristic.

See _drift_time_heuristic_impl() for a description of the algorithm.

Parameters:
Return type:

Array

reboost.hpge.psd.get_current_waveform(edep, drift_time, template, start, dt, range_t)

Estimate the current waveform.

Based on modelling the current as a sum over the current pulse model defined by the template.

\[A(t) = \sum_i E_i \times N f(t,dt_i,\vector{\theta})\]
Where:

  • $f(t)$ is the template

  • $vector{theta}$ are the parameters (sigma, p, tau)

  • $E_i$ and $dt_i$ are the deposited energy and drift time.

  • N is a normalisation term

Parameters:

  • edep (ak.Array) – Array of energies for each step

  • drift_time (ak.Array) – Array of drift times for each step

  • template (ArrayLike) – array of the template for the current waveforms, with 1 ns binning.

  • start (float) – first time value of the template

  • dt (float) – timestep (in ns) for the template.

  • range_t (tuple) – a range of times to search around

Returns:

A tuple of the time and current for the current waveform for this event.

Return type:

tuple(NDArray, NDArray)

reboost.hpge.psd.maximum_current(edep, drift_time, *, sigma, tail_fraction, tau, mean_AoE=0, get_timepoint=False)

Estimate the maximum current in the HPGe detector based on _estimate_current_impl().

Parameters:

  • edep (_Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes]) – Array of energies for each step.

  • drift_time (_Buffer | _SupportsArray[dtype[Any]] | _NestedSequence[_SupportsArray[dtype[Any]]] | bool | int | float | complex | str | bytes | _NestedSequence[bool | int | float | complex | str | bytes]) – Array of drift times for each step.

  • sigma (float) – Sigma parameter of the current pulse model.

  • tail_fraction (float) – Tail-fraction parameter of the current pulse.

  • tau (float) – Tail parameter of the current pulse

  • mean_AoE (float) – The mean AoE value for this detector (to normalise current pulses).

  • get_timepoint (bool) – Flag to return the time of the maximum current (relative to t0) instead of the current.

Returns:

An Array of the maximum current for each hit.

Return type:

Array

reboost.hpge.psd.r90(edep, xloc, yloc, zloc)

R90 HPGe pulse shape heuristic.

Parameters:

  • edep (Array) – array of energy.

  • xloc (Array) – array of x coordinate position.

  • yloc (Array) – array of y coordinate position.

  • zloc (Array) – array of z coordinate position.

Return type:

Array

reboost.hpge.surface module

reboost.hpge.utils module

class reboost.hpge.utils.HPGeScalarRZField(φ, r_units, z_units, φ_units)

Bases: NamedTuple

A scalar field defined in the cylindrical-like (r, z) HPGe plane.

Create new instance of HPGeScalarRZField(φ, r_units, z_units, φ_units)

Parameters:
_asdict()

Return a new dict which maps field names to their values.

_field_defaults = {}
_fields = ('φ', 'r_units', 'z_units', 'φ_units')
classmethod _make(iterable)

Make a new HPGeScalarRZField object from a sequence or iterable

_replace(**kwds)

Return a new HPGeScalarRZField object replacing specified fields with new values

r_units: Unit

Physical units of the coordinate r.

z_units: Unit

Physical units of the coordinate z.

φ: Callable

Scalar field, function of the coordinates (r, z).

φ_units: Unit

Physical units of the field.

reboost.hpge.utils.get_hpge_scalar_rz_field(filename, obj, field, out_of_bounds_val=nan, **kwargs)

Create an interpolator for a gridded scalar HPGe field defined on (r, z).

Reads from disk the following data structure:

FILENAME/
└── OBJ · struct{r,z,FIELD}
    ├── r · array<1>{real} ── {'units': 'UNITS'}
    ├── z · array<1>{real} ── {'units': 'UNITS'}
    └── FIELD · array<2>{real} ── {'units': 'UNITS'}

where FILENAME, OBJ and FIELD are provided as arguments to this function. obj is a Struct, r and z are one dimensional arrays specifying the radial and z coordinates of the rectangular grid — not the coordinates of each single grid point. In this coordinate system, the center of the p+ contact surface is at (0, 0), with the p+ contact facing downwards. field is instead a two-dimensional array specifying the field value at each grid point. The first and second dimensions are r and z, respectively. NaN values are interpreted as points outside the detector profile in the (r, z) plane.

Before returning a HPGeScalarRZField, the gridded field is fed to scipy.interpolate.RegularGridInterpolator.

Parameters:

  • filename (str) – name of the LH5 file containing the gridded scalar field.

  • obj (str) – name of the HDF5 dataset where the data is saved.

  • field (str) – name of the HDF5 dataset holding the field values.

  • out_of_bounds_val (int | float) – value to use to replace NaNs in the field values.

Return type:

HPGeScalarRZField