The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic light house program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey.

The HERD beam test at CERN is dedicated to verify the design of a 3-d and five-side sensitive calorimeter, the feasibility of WLSF + ICCD reading-out scheme. The energy resolution of electrons and protons, the angular resolution of electrons and the e/p separation capability will be measured by use of the CERN beam.

Collaborators of the test beam are from:

  • University of Perugia/INFN, Italy
  • University of Bari/INFN, Italy
  • University of Salento/INFN-Lecce, Italy
  • University of Geneva, Switzerland
  • Institute of High Energy Physics, China
  • Xi’an Institute of Optical and Precision Mechanics, China

Before the Beam

The CALO+ICCD protoype is scheduled to arrive CERN at least one week before the beam time. There are about fifteen participants from China, five of them (mechanical engineer, ICCD DAQ expert, electronics expert and contact person ) will arrival with the prototype, and the rest will arrival two days before the beam time. Ming will guide Chinese collaborators for the registration, dosimetry service. And power-on self-check and basic CR test and necessary adjustment of the prototype will be accomplished within the week. (including preliminary integration and test of scintillator trigger, sillicon ladder and calorimeter at the same time?).

Beam Time

The beam time for HERD is from 11-Nov to 20-Nov refer to the the beam schedule issued on 01-Sep-2015.

There are two kinds of run during the beam time: 11-Nov to 16-Nov, proton run; 16-Nov to 20-Nov, Pb run.

Note that the technical stop is NOT as usual (usually the slot is 10 hours form 08h to 18h in the same day). The techical stop is 24 hours for the proton run and 34 hours for the Pb run, which means the valid beam time is shorter than expected.



The HERD prototype is composed of 250 LYSO crystals, two ICCDs and two trigger PMTs. Each crystal with a dimension of 3*3*3 cm3 is contained in a CFRP grid. The space between crystals is controlled not to be larger than 3/5 mm in the horizontal/vertical direction. The 5*5*10 crystal array is designed to have the full shape of shower of SPS electrons contained in. So the main purpose of verifying the specification of electron's energy resolution can be reached. Two ICCDs, each having the capability of fast and weak light imaging, is taken use of to meet the requirement of large dynamic range from 1 MIP to 2000 MIPs. Each crystal is coupled with two WLS fibers. One fiber acting as low-range fiber has a single-end output to the low-range ICCD. While both ends of the other fiber are led out and read out by the high-range ICCD and trigger PMTs respectively. The ratio in amplitude between low and high range fibers is about 40 to 1. About 12*12 pixels on the CCD chip are allocated to one WLS fiber. So the energy deposition in the calorimeter can be derived by a 2-d image which includes 250 separate faculas.

The HERD trigger system consisting of two PMTs is mainly dedicated to the verification of energy measurement capability of ICCDs. While it is not designed to give triggers to the ICCDs. The trigger signal from the PS trigger system goes through the HERD trigger system before being input to the ICCDs. 249 out of 250 trigger fibers are coupled to one trigger PMT and the trigger fiber from the center crystal is read out by one separate PMT.

  • HERD prototype:

Plastic Scintillator Trigger System

The PS system consists of at least 4 plastic scintillators. One large area PS and two smaller PS with an area of 4*4 cm2 act as concidence detectors, the other large area PS with a hole acts as the anti-coincidence detector. The trigger signal from the PS system will be broadcasted to all the other systems, and the PS trigger no. will be recorded in the data files of all systems.

Please update...

Silicon Tracking System



For this BT the ladders are named, from the most upward to the closer to ICC: 0, 4, 8, 12, 14 (see Cluster.address). The ladder '12' had some problems so can be used just with the ion beam.

The Silicon Tracking System is based on the AMS silicon ladder detectors:


  • 110 μm for S-side (junction side) (X) (vertical at this BT)
  • 208 μm for K-side (ohmic side) (Y) (horizontal at this BT)
  • 1392 μm from last K-side strip on one silicon wafer to the first of the next one


Infos in the TTree:

The 'Event' contains few general informations and a container of all the clusters found with the zero suppression. Each Cluster has these raw informations:

  • Cluster.address: address (in unit of strip number, of the first strip in the cluster). The address for cluster on the S-side (or p-side, or Y coo) are ranging from 0-639. For K-side (or n-side, or X coo) are ranging from 640 to 1023.
  • Cluster.length: lenght (in unit of number of strips) of the cluster. Lenght=N means that the cluster is formed by the signals form N strips
  • Cluster.Signal[50]: signal value for the first min(50,lenght) strips in the cluster
  • Cluster.Noise[50]: noise value for the first min(50,lenght) strips in the cluster. This value is determined just during calibration so the very same channel, in the same run has the very same noise value. This can be used to evaluate the S/N ratio and apply a quality cut on it (strip by strip forming the ladder)
  • Cluster.Status[50]: not used
  • Cluster.ladder: number ID of the ladder to which the cluster belongs. For this BT the ladders were, from the most upward to the closer to ICC: 0, 4, 8, 12, 14.
  • Cluster.side: the side of the ladder in which there's the cluster. side=0 means S-side, side=1 means K-side. This information is essentially redundant wrt to the address.
  • Cluster.bad: not used
  • Cluster.golden: not used
  • Cluster.snratios: S/N for the whole cluster
  • Cluster.CNstatus: not used
  • Cluster.powbits: not used

Integration and Synchronize

The ICCD system, HERD trigger system, PS system and STK system are involved in the HERD beam test at CERN.

  • HERD_SPS_test_trigger_map151024.jpg:

Please update...

Instrument Support Platform

CALO+ICCD system will be placed on the top of GOLIATH in PPE134/H4. The Plastic scintillator and Silicon ladder will be placed on the platform used for DAMPE test beam at BAT.887.

Hardware Contibution

The crystal array and HERD trigger system are designed and developed in IHEP.

The two ICCD systems are contributed by XIOPM colleagues.

Please update...

Software Contibution

The Raw data from the two ICCDs is compressed and transfered to ROOT file in nearly real time. All the ROOT files are to be uploaded through internet cables to the laptop in the control room (and to the CERN server through WIFI or to be copied to a common computer by USB disk). The data of HERD trigger system will be processed in the same way.

ROOT files from all the four systems will be jointly analyzed to verify the working conditions of the beam and the systems.

  • Network in HERD SPS test:

Please update...

Following Events

The next vidyo meeting will be held on 4-Nov, 09h Europe time and 16h Beijing time respectively.

The next HERD Collaboration meeting will be held in January or early February of 2016 in Xi'an, China. The summing-up of the HERD beam test together with the future working plan will be discussed.


Collaborators from China prefered to live in PREVESSIN-MOENS-Residhome and rent several cars from CERN/company at Ferney-Voltaire.

A group of 4 IHEP people will arrive at CERN on Nov. 2nd. The other IHEP people will be at CERN on Nov. 7th.


-- MingXu - 2015-09-21

Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf HERDBT_Silicon_detector_details.pdf r1 manage 1014.0 K 2016-01-13 - 17:43 DomenicoDurso  
PDFpdf HERDBT_geom.pdf r1 manage 19.3 K 2015-12-17 - 12:34 MatteoDuranti  
PNGpng HERDBT_geom.png r1 manage 33.6 K 2015-12-17 - 12:36 MatteoDuranti  
Unknown file formatpptx HERDBT_geom.pptx r1 manage 53.9 K 2015-12-17 - 12:34 MatteoDuranti  
PNGpng HERDBT_pic.png r1 manage 479.3 K 2015-12-17 - 12:35 MatteoDuranti  
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