# Presentation: 580093

## D0SMT Radiation Monitoring

**Contents: **
** ****Radiation effects in silicon and impact on RunIIb**
** ****Dosimetry techniques**
** ****The BLM system**
** ****The finger diode system**
** ****TLDs and foils**
** ****Detector currents**
** ****Results so far**

## Radiation effects on Silicon

**Two major effects**
**Increased leakage current**
**More noise**
**Possible thermal runaway**

** ****Increase in Depletion voltage**
**Increases operating voltage of detectors**
**Change sensors from n to p type silicon**
**Will cause breakdown of coupling capacitors, microdischarge breakdown of p-n junction**
**   ****Both depend on temperature**

## BLM System

**BLM system **
**copy of run 1/current CDF system**
**Interfaced to beam abort – this is what currently dumps the beam**
**Far from silicon (downstream of calorimeter), large extrapolation to silicon dose.**
**Integral not very sensitive to small, continuous dose due to integration thresholds.**
**Logarithmic response – odd behavior and quantized jumps at low dose rates**
**Technical:**
**8 glass ion argon ion chambers (coke bottles).  **
**Very simple devices – no gain – integrate total charge**
**Large dynamic range – log amp in chassis**
**Processing in 2 CAMAC modules C336/C337 – do inversion of log response, keep rolling sums and fast FIFO buffer than can be dumped if the beam is aborted to examine dose at millisecond time scale**

## BLM Readout

**Chassis**
**circuit**

## BLM

**ACNET BLM  Variables**
**Alarms and limits**
**Rate/sec : D0BLXX**
**Integrated dose: D0BRXX**
**Rate/min: D0BAXX (set) **
**FIFO: D0BFXX**
**Locations:**
**UT – Upstream top (P side)****(monitored by MCR)**
**UB – Upstream bottom**
**UI – Upstream inner**
**UO – Upstream outer**
**D - downstream**

## BLM Calibration

**Our initial calibration found that the dose rate CDF was using for Run I was off by a factor of 7! Not a perfect system by any means...**

**Integral and rate response at 0.5 na.**** **

**BLM integral and rate response as a function of current**

**Normalized response**** **

**Integral and rate response at 70 na.**** **

## BLM Alarms and Limits

## The Finger Diode System

**Detectors- 24 one cm photodiodes at 4 radii**
**Provide MIP signals**
**Three electronics paths**
**Single particle scalers (thresh ~ 2.5 MIPs)**
**High gain integration**
**Low gain integration**
**Data fed to EPICS – not yet used for beam abort**
**Dynamic range from mrads/sec to Krads/sec**
**Original ADC system not sensitive to small losses – add scalers**

## Fingers during Shot Setup

**ADC Output **

**Scaler Output**

## Readout

**MCH3 2 VME crates**
**ADCs and scalers + NIM logic**
**Devices sensitive to noise during SMT readout**
**ADC jumps – solve in software?**
**Large scaler count rate – solved by gating**

## Finger Diode III

**The radmon Gui**

**Watch these**

- Online crate alive

- HV for BLMs (1500<HV<2200)

- Dose rates

- Temperatures

**New finger GUI**

## Finger GUI

- Makes ps file /projects/D0smt/radmon/RADMON_north_yyyymmdd_hhmmss.ps

- Outside ring positive value, inside negative (noise)
- Max scale between circles is 1 Rad/s, scale linear

- Inner two circles:
-       F-disk Fingers;
- Outer two circles:
-       H-disk Fingers

- Minimal height
- To show position

- Resize

- Disabled

- Colour coding
- of bars
- (self explanatory)

- _The radmon Circle plots_
**Wherever North is mentioned als South applies**

## Finger Archiver

**To look at data from the SMT finger channel archiver: > cd /projects/archive/radmon/current ****> ls ****20011217-000000  archive_active.lck  dir.20011217-095540  radmon_rad_low.cfg ****20011218-000000  cfg                 log                  radmon_scaler.cfg ****20011219-000000  config_file         radmon_rad_high.cfg  radmon_temp.cfg ****20011220-000000  core                radmon_rad_int.cfg ****> setup d0online ******** setup D0RunII t01.67.00 ****> setup chan_archiver ****> Xarr.py dir.20011217-095540 & !paste name of current directory ****You then enter device names in the Xarr window, * can be used as a wild card. ****Names are: ****SMT_FINGER_AAANNN/XXX**** **
**Where : **
**AAA: IFN, IFS, OFN, OFS, IHN, IHS, OHN, OHS**** **
**I: inner radius device ****O: outer radius device ****F: F Disk ****H: H Disk ****N: North ****S: South ****NNN: finger angle (12:00 = 0 degrees)**** **
**F: 45,105,165,225,285,345 ****H: 0,60,120,180,240,300 ****XXX: RATE,RLVH,RLVL,INT**** **
**RATE: scaler rate ~ 1/3 x MIP rate (**_**[working channels](http://d0server1.fnal.gov/projects/silicon/www/radiation/scaler_working.html)**_**) ****INT : rolling sum of scaler rate. ****RLVH: Calculated dose rate from currents, high gain channel ****RLVL: Calculated dose rate from currents, low gain channel**

## Finger Diode II

**Typical store – shot setup and normal running**

**Effects of looping tracks on  silicon**
**Dose  - compare with CDF at 1.5 T**

## Contributions of Luminosity and Halo

**Technique – losses during a store have different shapes for halo and luminosity.  Normalize to mid –store and fit finger rates to shapes of the luminosity and p/p halo rates. This gives us a rough idea of how losses contribute to irradiation.**

- Rates for store 2121.  Fit is to pbar, p halo and luminosity

| Name | Three parameter fit | Two Parameter fit |
| --- | --- | --- |
| Phalo factor | 0.150 | 0.250 |
| Ahalo factor | 0.121 |  |
| Lum Factor | 0.359 | 0.378 |
| Lum fraction | 0.57 | 0.60 |

## TLDs

**TLD 600 (******** and neutrons)**
**TLD 700 (******** only)**
**Calibrated to few % but only linear to ~ 5-10 Krad**
**Added Al foils to integrate larger doses (1 year)**
**Installed removable system during shutdown**

## Dose estimate

- Particle flux as calculated from leakage current increase as a function of radius.  Correct for temperature, area, annealing ...
- Errors on the D0 points are statistical only