Add data backup methods

data/tdc.py

@@ -199,11 +199,18 @@ class TDCSpill:
     def __repr__(self):
         return f'TDCSpill({self.detector}, length={self.length:g}s, counts={self.counts})'
 
-    
-    
-    
-    
-    
+    def to_file(self, fname):
+        """Save the spill to a file in compressed npz format
+        """
+        np.savez_compressed(fname, header=self.header, data=self.data, time_offset=self.time_offset)
+
+    @classmethod
+    def from_file(self, fname):
+        """Load the spill from a file in compressed npz format
+        """
+        if not fname.endswith(".npz"): raise ValueError("fname must be a *.npz file. To load *.dat files, use TDCData.from_file(...) instead.")
+        with np.load(fname) as f:
+            return TDCSpill(f['header'], f['data'], f['time_offset'].item())
     
     
 @dataclass