diff --git a/eic_data.yaml b/eic_data.yaml
index ca842a2b1759a9d155a3b7ebdee0af68af9644b3..fc73ad6316d9953f42459636eb44e29708743063 100644
--- a/eic_data.yaml
+++ b/eic_data.yaml
@@ -72,6 +72,13 @@ components :
       - double cell_y
       - double cell_z
 
+  eic::BaseHit :
+    Members :
+      - double x
+      - double y
+      - double z
+      - double E
+
   eic::ElectronBeam :
     Members :
       - float eEnergy
@@ -336,16 +343,15 @@ datatypes :
     Description: "Layer for Imaging Calorimeter"
     Author: "C. Peng"
     Members:
-      - int                  nhits           // Number of hits
-      - float                edep            // Energy deposit
-      - float                radius          // Shower radius
-      - float                skewness        // Skewness of hits distribution
-      - float                chi2            // Edep chi2
-      - float                x0cum           // estimated radiation length before this layer
-      - eic::VectorXYZ       position        // Global center position.
-      - eic::VectorPolar     polar           // Global center position in polar coordinates
-    OneToManyRelations:
-      - eic::CalorimeterHit hits             // Hits belong to this layer
+      - int                  nhits          // Number of hits
+      - float                edep           // Energy deposit
+      - float                radius         // Shower radius
+      - float                skewness       // Skewness of hits distribution
+      - float                chi2           // Edep chi2
+      - float                x0cum          // estimated radiation length before this layer
+      - eic::VectorXYZ       position       // Global center position.
+      - eic::VectorPolar     polar          // Global center position in polar coordinates
+      - std::array<eic::BaseHit, 100> hits  // hits x data
 
   eic::ImagingCluster:
     Description: "Cluster for Imaging Calorimeter"