diff --git a/docs/examples/particle_examples.ipynb b/docs/examples/particle_examples.ipynb
index f96320c..fef7f5d 100644
--- a/docs/examples/particle_examples.ipynb
+++ b/docs/examples/particle_examples.ipynb
@@ -10,14 +10,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:16.493563Z",
-     "iopub.status.busy": "2024-10-17T23:20:16.493231Z",
-     "iopub.status.idle": "2024-10-17T23:20:16.756224Z",
-     "shell.execute_reply": "2024-10-17T23:20:16.755978Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "# Nicer plotting\n",
@@ -37,14 +30,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:16.757736Z",
-     "iopub.status.busy": "2024-10-17T23:20:16.757618Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.066823Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.066533Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "from pmd_beamphysics import ParticleGroup"
@@ -53,14 +39,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.068335Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.068183Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.075538Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.075293Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P = ParticleGroup(\"data/bmad_particles2.h5\")\n",
@@ -70,14 +49,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.097947Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.097804Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.100584Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.100339Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.energy"
@@ -86,14 +58,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.101830Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.101729Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.104641Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.104411Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P[\"mean_energy\"], P.units(\"mean_energy\")"
@@ -102,14 +67,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.105799Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.105706Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.117036Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.116807Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.where(P.x < P[\"mean_x\"])"
@@ -118,14 +76,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.118234Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.118138Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.568107Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.567825Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "a = P.plot(\"x\", \"px\", figsize=(8, 8))"
@@ -134,14 +85,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.570337Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.570233Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.813384Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.813006Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.write_elegant(\"elegant_particles.txt\", verbose=True)"
@@ -164,14 +108,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.818500Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.818325Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.821375Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.820860Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.x"
@@ -187,14 +124,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.823608Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.823471Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.826057Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.825834Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.gamma"
@@ -210,14 +140,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.827703Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.827508Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.832477Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.832144Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "len(P), P[\"n_particle\"]"
@@ -240,14 +163,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.840376Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.840165Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.844354Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.843905Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.avg(\"gamma\"), P.std(\"p\")"
@@ -263,14 +179,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.846001Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.845906Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.851579Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.851273Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.cov(\"x\", \"px\", \"y\", \"kinetic_energy\")"
@@ -286,14 +195,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.853476Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.853188Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.860581Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.860286Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P[\"sigma_x\"], P[\"sigma_energy\"], P[\"min_y\"], P[\"norm_emit_x\"], P[\"norm_emit_4d\"]"
@@ -309,14 +211,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.862271Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.862162Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.866196Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.865886Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P[\"cov_x__kinetic_energy\"]"
@@ -332,14 +227,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.867645Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.867546Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.874795Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.874415Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "H, edges = P.histogramdd(\"t\", \"delta_pz\", bins=(5, 10))\n",
@@ -358,14 +246,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.876510Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.876297Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.916863Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.916585Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "ss = P.slice_statistics(\"norm_emit_x\")\n",
@@ -382,14 +263,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.918784Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.918628Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.986930Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.986674Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "ss = P.slice_statistics(\"norm_emit_x\", \"norm_emit_y\", \"twiss\")\n",
@@ -419,14 +293,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.988506Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.988404Z",
-     "iopub.status.idle": "2024-10-17T23:20:17.995209Z",
-     "shell.execute_reply": "2024-10-17T23:20:17.994828Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.twiss(\"x\")"
@@ -442,14 +309,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:17.996575Z",
-     "iopub.status.busy": "2024-10-17T23:20:17.996481Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.090868Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.090588Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.twiss(\"xy\", fraction=0.95)"
@@ -465,14 +325,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.092851Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.092732Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.101285Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.100955Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P2 = P.twiss_match(beta=30, alpha=-3, plane=\"x\")\n",
@@ -493,14 +346,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.102934Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.102784Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.128067Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.127790Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.resample()"
@@ -516,14 +362,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.129460Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.129369Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.137052Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.136774Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.resample(1000)"
@@ -532,14 +371,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.138293Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.138204Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.396743Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.396500Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.resample(1000).plot(\"x\", \"px\", bins=100)"
@@ -558,14 +390,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.398128Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.398013Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.400353Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.400088Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "(\n",
@@ -580,14 +405,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.401556Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.401460Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.403371Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.403136Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.units(\"mean_energy\")"
@@ -596,14 +414,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.404591Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.404499Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.406349Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.406148Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "str(P.units(\"cov_x__kinetic_energy\"))"
@@ -621,14 +432,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.407490Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.407417Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.410062Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.409837Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.std(\"z\"), P.std(\"t\")"
@@ -644,14 +448,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.411207Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.411135Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.413231Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.413014Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "t0 = P.avg(\"t\")\n",
@@ -668,14 +465,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.414455Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.414376Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.417177Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.416948Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.drift_to_t(t0)"
@@ -691,14 +481,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.418394Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.418317Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.424567Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.424343Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.std(\"z\"), P.avg(\"t\"), set(P.t)"
@@ -718,14 +501,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.425709Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.425638Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.427775Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.427538Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.status[0:10] = 0\n",
@@ -742,14 +518,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.428889Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.428814Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.448042Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.447783Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P0 = P.where(P.status == 0)\n",
@@ -767,14 +536,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.449394Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.449317Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.451377Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.451179Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P2 = P1.copy()"
@@ -790,14 +552,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.452540Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.452467Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.454606Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.454384Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P2.charge = 9.8765e-12\n",
@@ -814,14 +569,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.455747Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.455676Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.457416Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.457207Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "\"id\" in P2"
@@ -837,14 +585,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.458547Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.458474Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.460471Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.460235Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P2.id, \"id\" in P2"
@@ -860,14 +601,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.461634Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.461561Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.462964Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.462746Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "import h5py\n",
@@ -877,14 +611,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.464211Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.464142Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.473958Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.473683Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "newh5file = \"particles.h5\"\n",
@@ -906,14 +633,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.475337Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.475258Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.478010Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.477801Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "for key in [\"x\", \"px\", \"y\", \"py\", \"z\", \"pz\", \"t\", \"status\", \"weight\", \"id\"]:\n",
@@ -931,14 +651,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.479257Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.479167Z",
-     "iopub.status.idle": "2024-10-17T23:20:18.483688Z",
-     "shell.execute_reply": "2024-10-17T23:20:18.483461Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P2 == P"
@@ -954,14 +667,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:18.484951Z",
-     "iopub.status.busy": "2024-10-17T23:20:18.484870Z",
-     "iopub.status.idle": "2024-10-17T23:20:19.077238Z",
-     "shell.execute_reply": "2024-10-17T23:20:19.076925Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.write_astra(\"astra.dat\")"
@@ -970,14 +676,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:19.078673Z",
-     "iopub.status.busy": "2024-10-17T23:20:19.078564Z",
-     "iopub.status.idle": "2024-10-17T23:20:19.205207Z",
-     "shell.execute_reply": "2024-10-17T23:20:19.204803Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "!head astra.dat"
@@ -993,14 +692,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:19.207284Z",
-     "iopub.status.busy": "2024-10-17T23:20:19.206964Z",
-     "iopub.status.idle": "2024-10-17T23:20:19.217583Z",
-     "shell.execute_reply": "2024-10-17T23:20:19.217277Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.write(\"particles.h5\")"
@@ -1025,14 +717,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:19.219281Z",
-     "iopub.status.busy": "2024-10-17T23:20:19.219174Z",
-     "iopub.status.idle": "2024-10-17T23:20:19.628355Z",
-     "shell.execute_reply": "2024-10-17T23:20:19.628099Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.plot(\"x\")"
@@ -1048,14 +733,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:19.629649Z",
-     "iopub.status.busy": "2024-10-17T23:20:19.629563Z",
-     "iopub.status.idle": "2024-10-17T23:20:19.849704Z",
-     "shell.execute_reply": "2024-10-17T23:20:19.849459Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.slice_plot(\"norm_emit_x\", \"norm_emit_y\", ylim=(0, 1e-6))"
@@ -1064,14 +742,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:19.850981Z",
-     "iopub.status.busy": "2024-10-17T23:20:19.850871Z",
-     "iopub.status.idle": "2024-10-17T23:20:20.158771Z",
-     "shell.execute_reply": "2024-10-17T23:20:20.158531Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.plot(\"z\", \"x\")"
@@ -1087,14 +758,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:20.160286Z",
-     "iopub.status.busy": "2024-10-17T23:20:20.160188Z",
-     "iopub.status.idle": "2024-10-17T23:20:20.334573Z",
-     "shell.execute_reply": "2024-10-17T23:20:20.334321Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.slice_plot(\"sigma_x\", slice_key=\"Jx\")"
@@ -1110,14 +774,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:20.335992Z",
-     "iopub.status.busy": "2024-10-17T23:20:20.335891Z",
-     "iopub.status.idle": "2024-10-17T23:20:20.643612Z",
-     "shell.execute_reply": "2024-10-17T23:20:20.643380Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.plot(\"x\", \"px\", ellipse=True)"
@@ -1133,14 +790,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:20.645203Z",
-     "iopub.status.busy": "2024-10-17T23:20:20.645094Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.062886Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.062635Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "fig = P.plot(\"x\", return_figure=True)\n",
@@ -1159,14 +809,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:21.064216Z",
-     "iopub.status.busy": "2024-10-17T23:20:21.064132Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.139837Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.139604Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "import copy\n",
@@ -1188,14 +831,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:21.141053Z",
-     "iopub.status.busy": "2024-10-17T23:20:21.140946Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.494659Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.494422Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "P.plot(\"delta_z\", \"delta_p\", figsize=(8, 6))"
@@ -1211,14 +847,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:21.496329Z",
-     "iopub.status.busy": "2024-10-17T23:20:21.496222Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.599826Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.599600Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "H, edges = P.histogramdd(\"delta_z\", \"delta_p\", bins=(150, 150))\n",
@@ -1227,6 +856,57 @@
     "plt.imshow(H.T, origin=\"lower\", extent=extent, aspect=\"auto\", vmin=1e-15, cmap=cmap)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Splitting\n",
+    "\n",
+    "It is often useful to split particles along a key dimension for analysis. This method will split into chunks with approximately equal numbers of particles."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "P.split(n_chunks=3, key=\"z\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Fractional split will use weights to partition the particles. "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "P.fractional_split(fractions=[0.1, 0.9], key=\"z\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This is useful for splitting particles into head, core, and tail parts. Here, the 5% of the charge is in the tail, 90% is in the core, and 5 % is in the head:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "for p in P.fractional_split(key=\"z\", fractions=[0.05, 0.95]):\n",
+    "    p.plot(\"z\", \"energy\", bins=100, figsize=(3, 3))"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -1239,14 +919,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:21.601117Z",
-     "iopub.status.busy": "2024-10-17T23:20:21.601028Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.603036Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.602808Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "from pmd_beamphysics import particle_paths\n",
@@ -1266,14 +939,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:21.604195Z",
-     "iopub.status.busy": "2024-10-17T23:20:21.604119Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.606826Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.606618Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "ppaths = particle_paths(h5)\n",
@@ -1290,14 +956,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:21.608025Z",
-     "iopub.status.busy": "2024-10-17T23:20:21.607926Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.610352Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.610162Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "ph5 = h5[ppaths[0]]\n",
@@ -1314,14 +973,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:21.611431Z",
-     "iopub.status.busy": "2024-10-17T23:20:21.611344Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.615151Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.614931Z"
-    }
-   },
+   "metadata": {},
    "outputs": [],
    "source": [
     "for component in all_components(ph5):\n",
@@ -1340,12 +992,6 @@
    "cell_type": "code",
    "execution_count": null,
    "metadata": {
-    "execution": {
-     "iopub.execute_input": "2024-10-17T23:20:21.616286Z",
-     "iopub.status.busy": "2024-10-17T23:20:21.616194Z",
-     "iopub.status.idle": "2024-10-17T23:20:21.618548Z",
-     "shell.execute_reply": "2024-10-17T23:20:21.618357Z"
-    },
     "tags": []
    },
    "outputs": [],
@@ -1374,7 +1020,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.7"
+   "version": "3.13.0"
   },
   "vscode": {
    "interpreter": {
diff --git a/pmd_beamphysics/particles.py b/pmd_beamphysics/particles.py
index bca939b..6c8d8ac 100644
--- a/pmd_beamphysics/particles.py
+++ b/pmd_beamphysics/particles.py
@@ -2,6 +2,7 @@
 import os
 import pathlib
 from copy import deepcopy
+from typing import Union
 
 import numpy as np
 from h5py import File
@@ -1138,6 +1139,66 @@ def slice_plot(
     def split(self, n_chunks=100, key="z"):
         return split_particles(self, n_chunks=n_chunks, key=key)
 
+    def fractional_split(self, fractions: Union[float, int, list], key: str):
+        """
+        Split particles based on a given array key and a list of specified fractions or a single fraction.
+
+        Parameters
+        ----------
+        fractions : float or list of float
+            A fraction or a list of fractions used for splitting the particles. All values must be between 0 and 1 (exclusive).
+
+        key : str
+            The attribute of particles to be used for sorting and splitting (e.g., 'z' for longitudinal position).
+
+        Returns
+        -------
+        particle_groups : list of ParticleGroup
+            A list of ParticleGroup objects, each representing a subset of particles based on the specified fractions.
+
+        Description
+        -----------
+        This function splits the given group of particles into multiple subsets based on the provided attribute (e.g., position).
+        The splits are determined such that each specified fraction of the total particle weights is separated.
+        The function first sorts the particles by the specified key, computes the cumulative sum of weights,
+        and determines the split values. It then returns a list of ParticleGroup objects representing the split subsets.
+
+        """
+
+        # Ensure fractions is a list
+        if isinstance(fractions, (float, int)):
+            fractions = [fractions]
+
+        # Validate fraction values
+        if any(f <= 0 or f >= 1 for f in fractions):
+            raise ValueError("All fraction values must be between 0 and 1 (exclusive)")
+
+        # Sort particles by the specified key
+        ixs = np.argsort(self[key])
+        sorted_particles = self[ixs]
+
+        # Sorted weights
+        ws = sorted_particles.weight
+        total_weight = np.sum(ws)
+        cw = np.cumsum(ws) / total_weight
+
+        # Use vectorized searchsorted to determine split indices
+        fractions = np.array(fractions)
+        split_indices = np.searchsorted(cw, fractions, side="right")
+
+        # Create ParticleGroup subsets for each split
+        particle_groups = []
+        previous_index = 0
+        for isplit in split_indices:
+            particle_groups.append(sorted_particles[previous_index:isplit])
+            previous_index = isplit
+
+        # Add the remaining particles to the last group
+        if previous_index < len(sorted_particles):
+            particle_groups.append(sorted_particles[previous_index:])
+
+        return particle_groups
+
     def copy(self):
         """Returns a deep copy"""
         return deepcopy(self)
diff --git a/tests/test_particlegroup.py b/tests/test_particlegroup.py
index 5fccc5a..01c0061 100644
--- a/tests/test_particlegroup.py
+++ b/tests/test_particlegroup.py
@@ -85,3 +85,8 @@ def test_write_reload(tmp_path):
 
     P2.x += 1
     assert P != P2
+
+
+def test_fractional_split():
+    head, tail = P.fractional_split(0.5, "t")
+    head, core, tail = P.fractional_split((0.1, 0.9), "t")