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dimensions of particle physics

dimensions of particle physics

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How to make CERN’s most delicious detector

November 11, 2013

How to make CERN’s most delicious detector

Three University of Minnesota graduate students took their particle physics skills to the kitchen to create an edible model of the CMS detector, and symmetry has the recipe.

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Particle physics has never been so sweet. Courtesy of a group of graduate students from the University of Minnesota, you can now create your own model of the detector for the CMS experiment at the Large Hadron Collider―in dessert form.

The CMS detector is an elaborate apparatus that measures the type, energy and momentum of particles that erupt from particle collisions inside the LHC. It stands about five stories tall and weighs 14,500 tons.

Inspired by students who built a miniature version of the grand experiment out of Legos, Minnesota graduate students Alexey Finkel, Pam Vo and Joe Pastika decided it was time to make their own model—out of wafers, chocolate, gelatin and other delicious goodness.

It required a little creativity and a lot of toothpicks. But after weeks of planning and two solid days of baking, the group successfully produced the first-ever edible CMS replica. Follow the recipe below to make a CMS detector of your own.

Bakers' note: Before assembling the CMS cake, you will first need to make all of the component parts: the phyllo dough tracker, the gelatin electromagnetic calorimeter, the cookie hadronic calorimeter, the chocolate solenoid magnet, the wafer muon chambers, the yellow cake return yoke, and the brownie hadronic forward calorimeters. Even in the kitchen, this experiment is no small undertaking!

Phyllo dough tracker

The tracker is the innermost component of the CMS detector. It consists of layers of silicon detectors that record the paths of charged particles.


  • phyllo dough
  • butter
  • cinnamon
  • honey


  1. Unroll a sheet of phyllo dough and spread with melted butter.
  2. Sprinkle with cinnamon and drizzle with honey.
  3. Repeat 4 more times to create a stack of layers.
  4. Roll the stack into a cylinder and bake per package directions or until golden brown.


Gelatin electromagnetic calorimeter

The electromagnetic calorimeter—or ECAL for short—is made out of 76,000 transparent lead tungstate crystals. It records the direction and energy of electrons and photons.


  • 6 tbsp sugar
  • 23 cup lime juice
  • 4 tbsp corn syrup, separated
  • 4 tbsp unflavored gelatin


  1. Prepare a small pan by wetting it lightly with water.
  2. Place the gelatin in 1/4 cup cold water and let soften for about 5 minutes.
  3. Place the lime juice, sugar and corn syrup in a medium saucepan over medium heat and stir until sugar dissolves.
  4. Stir in the gelatin and continue stirring until gelatin dissolves.
  5. Pour the mixture into the pan and let set (about 1 hour in the refrigerator).


Cookie hadronic calorimeter

The hadronic calorimeter—or HCAL—consists of layers of scintillating plastic and brass that generate light when a hadron—such as a proton or neutron—passes through them.


  • 1 ½ cups brown sugar
  • ½ cup melted butter
  • 2 eggs
  • 1 tsp vanilla extract
  • 1 ½ cups flour
  • ½ tsp baking powder
  • ½ tsp salt


  1. Mix brown sugar, butter, eggs and vanilla in a large bowl.
  2. Mix flour, baking powder and salt separately, and then add to butter-sugar mixture.
  3. Spread into greased 13x9-inch pan and bake at 350 degrees Fahrenheit for 18 to 20 minutes or until cookie bars are rigid.

Chocolate solenoid magnet

The solenoid magnet is a superconducting niobium-titanium coil that creates a powerful magnetic field that bends the trajectory of the charged particles created during a collision.


  • 1 lb dark chocolate
  • cylindrical container (such as a 1L beaker)
  • cylindrical inner mandrel (such as a tall can or glass)
  • parchment paper and plastic wrap


  1. To mold this hollow chocolate cylinder, line a large cylindrical container with parchment paper.
  2. Pour chocolate into the vessel, and then insert a parchment-lined mandrel into the center of the vessel to create a large cylindrical space in the middle.
  3. Let set until hard, and then carefully remove chocolate cylinder from container. To remove the mandrel, cut the cylinder axially.

Wafer muon chambers

The CMS muon chambers are filled with a gas that creates a shower of ionized particles when a muon bumps into an atom and knocks out an electron.


  • 2 packages wafer sheets


  • No additional preparation.

Yellow cake return yoke

The return yoke is a series of iron plates that shapes the magnetic field created by the solenoid magnet.


  • 1 box yellow cake mix
  • 1 cup softened butter
  • 2 lb powdered sugar
  • 4 tsp vanilla or 1 tsp almond extract
  • red food coloring


  1. Follow cake mix directions and bake in a 9x13-inch pan.
  2. For frosting, cream sugar into softened butter, adding sugar slowly until the mixture becomes frosting-like (you may not need all the sugar). If it is too thick, add milk 1 tbsp at a time until it is a spreadable consistency.
  3. Add extract to flavor.
  4. Split the frosting into 2 batches and color 1 batch red.

Brownie hadronic forward calorimeters

The hadronic forward calorimeters—or HF—are part of the HCAL and located at the ends of the detector close to the beam pipe. The HF records the energy of particles that escape particle collisions at shallow angles.


  • 1 box brownie mix


  • Follow brownie mix instructions and bake in a 9x9-inch pan.

CMS cake assembly

Bakers’ note: From here on, the process becomes less of a science and more an art form. Some experimentation and patience will be required.

  1. First, fill the chocolate solenoid magnet with the cookie hadronic calorimeter, the gelatin electromagnetic calorimeter and the phyllo dough tracker. Start by cutting out two circles of cookie hadronic calorimeter the right size to seal the two ends of the assembled chocolate solenoid magnet. Put them in place, and then line the insides of the chocolate solenoid magnet with strips of cookie hadronic calorimeter.
  2. On top of the layer of cookie hadronic calorimeter, add a second layer of strips of gelatin electromagnetic calorimeter.
  3. Place the phyllo dough tracker in the center of the chocolate solenoid magnet, on top of the layers of cookie and gelatin, and seal inside with a set of gelatin and cookie disks on each end. Then seal the two halves together using melted chocolate. Place in freezer to harden.
  4. Create six layers of wafer muon chambers and yellow cake return yoke by sandwiching rectangles of yellow cake between rectangular wafers, securing with white frosting. Decorate outer layers with red frosting. These layers should be slightly longer than the chocolate solenoid magnet.
  5. Support bottom of cake with a stand 0.5 inches high.
  6. Form layers of wafer muon chambers and yellow cake return yoke into a bottomless hexagon around the chocolate. Reinforce with toothpicks.
  7. Cut out hexagonal wafer muon chambers to form the endcaps of the detector. Using frosting, attach one endcap to each end with a layer of yellow cake return yoke in between the wafer and the rest of detector. Reinforce with toothpicks. Decorate outsides with red frosting.
  8. Cut two cubes of brownie hadronic forward calorimeter and attach them to the centers of the endcaps using toothpicks.
  9. Admire your work, and enjoy your dessert!
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Courtesy of Alexey Finkel, Pamela Vo and Nathaniel Pastika